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| author | Chet Ramey <chet.ramey@case.edu> | 2020-12-06 15:51:17 -0500 |
|---|---|---|
| committer | Chet Ramey <chet.ramey@case.edu> | 2020-12-06 15:51:17 -0500 |
| commit | 8868edaf2250e09c4e9a1c75ffe3274f28f38581 (patch) | |
| tree | d9a7812ab6cd2f45c5021755c4c094b19dab1b51 /doc/bash.0 | |
| parent | 36f2c406ff27995392a9247dfa90672fdaf7dc43 (diff) | |
| download | bash-8868edaf2250e09c4e9a1c75ffe3274f28f38581.tar.gz | |
bash-5.1 distribution sources and documentationbash-5.1
Diffstat (limited to 'doc/bash.0')
| -rw-r--r-- | doc/bash.0 | 4476 |
1 files changed, 2355 insertions, 2121 deletions
@@ -9,7 +9,7 @@ SSYYNNOOPPSSIISS bbaasshh [options] [command_string | file] CCOOPPYYRRIIGGHHTT - Bash is Copyright (C) 1989-2018 by the Free Software Foundation, Inc. + Bash is Copyright (C) 1989-2020 by the Free Software Foundation, Inc. DDEESSCCRRIIPPTTIIOONN BBaasshh is an sshh-compatible command language interpreter that executes @@ -23,86 +23,85 @@ DDEESSCCRRIIPPTTIIOONN OOPPTTIIOONNSS All of the single-character shell options documented in the description of the sseett builtin command, including --oo, can be used as options when - the shell is invoked. In addition, bbaasshh interprets the following - options when it is invoked: + the shell is invoked. In addition, bbaasshh interprets the following op- + tions when it is invoked: --cc If the --cc option is present, then commands are read from the first non-option argument _c_o_m_m_a_n_d___s_t_r_i_n_g. If there are argu- - ments after the _c_o_m_m_a_n_d___s_t_r_i_n_g, the first argument is - assigned to $$00 and any remaining arguments are assigned to - the positional parameters. The assignment to $$00 sets the - name of the shell, which is used in warning and error mes- - sages. + ments after the _c_o_m_m_a_n_d___s_t_r_i_n_g, the first argument is as- + signed to $$00 and any remaining arguments are assigned to the + positional parameters. The assignment to $$00 sets the name of + the shell, which is used in warning and error messages. --ii If the --ii option is present, the shell is _i_n_t_e_r_a_c_t_i_v_e. --ll Make bbaasshh act as if it had been invoked as a login shell (see IINNVVOOCCAATTIIOONN below). - --rr If the --rr option is present, the shell becomes _r_e_s_t_r_i_c_t_e_d + --rr If the --rr option is present, the shell becomes _r_e_s_t_r_i_c_t_e_d (see RREESSTTRRIICCTTEEDD SSHHEELLLL below). - --ss If the --ss option is present, or if no arguments remain after - option processing, then commands are read from the standard - input. This option allows the positional parameters to be - set when invoking an interactive shell or when reading input + --ss If the --ss option is present, or if no arguments remain after + option processing, then commands are read from the standard + input. This option allows the positional parameters to be + set when invoking an interactive shell or when reading input through a pipe. - --DD A list of all double-quoted strings preceded by $$ is printed - on the standard output. These are the strings that are sub- + --DD A list of all double-quoted strings preceded by $$ is printed + on the standard output. These are the strings that are sub- ject to language translation when the current locale is not CC - or PPOOSSIIXX. This implies the --nn option; no commands will be + or PPOOSSIIXX. This implies the --nn option; no commands will be executed. [[--++]]OO [[_s_h_o_p_t___o_p_t_i_o_n]] - _s_h_o_p_t___o_p_t_i_o_n is one of the shell options accepted by the - sshhoopptt builtin (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). If + _s_h_o_p_t___o_p_t_i_o_n is one of the shell options accepted by the + sshhoopptt builtin (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). If _s_h_o_p_t___o_p_t_i_o_n is present, --OO sets the value of that option; ++OO - unsets it. If _s_h_o_p_t___o_p_t_i_o_n is not supplied, the names and - values of the shell options accepted by sshhoopptt are printed on - the standard output. If the invocation option is ++OO, the + unsets it. If _s_h_o_p_t___o_p_t_i_o_n is not supplied, the names and + values of the shell options accepted by sshhoopptt are printed on + the standard output. If the invocation option is ++OO, the output is displayed in a format that may be reused as input. - ---- A ---- signals the end of options and disables further option - processing. Any arguments after the ---- are treated as file- + ---- A ---- signals the end of options and disables further option + processing. Any arguments after the ---- are treated as file- names and arguments. An argument of -- is equivalent to ----. - BBaasshh also interprets a number of multi-character options. These - options must appear on the command line before the single-character - options to be recognized. + BBaasshh also interprets a number of multi-character options. These op- + tions must appear on the command line before the single-character op- + tions to be recognized. ----ddeebbuuggggeerr Arrange for the debugger profile to be executed before the shell - starts. Turns on extended debugging mode (see the description + starts. Turns on extended debugging mode (see the description of the eexxttddeebbuugg option to the sshhoopptt builtin below). ----dduummpp--ppoo--ssttrriinnggss - Equivalent to --DD, but the output is in the GNU _g_e_t_t_e_x_t ppoo (por- + Equivalent to --DD, but the output is in the GNU _g_e_t_t_e_x_t ppoo (por- table object) file format. ----dduummpp--ssttrriinnggss Equivalent to --DD. - ----hheellpp Display a usage message on standard output and exit success- + ----hheellpp Display a usage message on standard output and exit success- fully. ----iinniitt--ffiillee _f_i_l_e ----rrccffiillee _f_i_l_e Execute commands from _f_i_l_e instead of the standard personal ini- - tialization file _~_/_._b_a_s_h_r_c if the shell is interactive (see - IINNVVOOCCAATTIIOONN below). + tialization file _~_/_._b_a_s_h_r_c if the shell is interactive (see IINN-- + VVOOCCAATTIIOONN below). ----llooggiinn Equivalent to --ll. ----nnooeeddiittiinngg - Do not use the GNU rreeaaddlliinnee library to read command lines when + Do not use the GNU rreeaaddlliinnee library to read command lines when the shell is interactive. ----nnoopprrooffiillee - Do not read either the system-wide startup file _/_e_t_c_/_p_r_o_f_i_l_e or - any of the personal initialization files _~_/_._b_a_s_h___p_r_o_f_i_l_e, - _~_/_._b_a_s_h___l_o_g_i_n, or _~_/_._p_r_o_f_i_l_e. By default, bbaasshh reads these - files when it is invoked as a login shell (see IINNVVOOCCAATTIIOONN - below). + Do not read either the system-wide startup file _/_e_t_c_/_p_r_o_f_i_l_e or + any of the personal initialization files _~_/_._b_a_s_h___p_r_o_f_i_l_e, + _~_/_._b_a_s_h___l_o_g_i_n, or _~_/_._p_r_o_f_i_l_e. By default, bbaasshh reads these + files when it is invoked as a login shell (see IINNVVOOCCAATTIIOONN be- + low). ----nnoorrcc Do not read and execute the personal initialization file - _~_/_._b_a_s_h_r_c if the shell is interactive. This option is on by - default if the shell is invoked as sshh. + _~_/_._b_a_s_h_r_c if the shell is interactive. This option is on by de- + fault if the shell is invoked as sshh. ----ppoossiixx - Change the behavior of bbaasshh where the default operation differs + Change the behavior of bbaasshh where the default operation differs from the POSIX standard to match the standard (_p_o_s_i_x _m_o_d_e). See - SSEEEE AALLSSOO below for a reference to a document that details how + SSEEEE AALLSSOO below for a reference to a document that details how posix mode affects bash's behavior. ----rreessttrriicctteedd @@ -112,103 +111,102 @@ OOPPTTIIOONNSS Equivalent to --vv. ----vveerrssiioonn - Show version information for this instance of bbaasshh on the stan- + Show version information for this instance of bbaasshh on the stan- dard output and exit successfully. AARRGGUUMMEENNTTSS If arguments remain after option processing, and neither the --cc nor the - --ss option has been supplied, the first argument is assumed to be the - name of a file containing shell commands. If bbaasshh is invoked in this - fashion, $$00 is set to the name of the file, and the positional parame- - ters are set to the remaining arguments. BBaasshh reads and executes com- - mands from this file, then exits. BBaasshh's exit status is the exit sta- - tus of the last command executed in the script. If no commands are - executed, the exit status is 0. An attempt is first made to open the + --ss option has been supplied, the first argument is assumed to be the + name of a file containing shell commands. If bbaasshh is invoked in this + fashion, $$00 is set to the name of the file, and the positional parame- + ters are set to the remaining arguments. BBaasshh reads and executes com- + mands from this file, then exits. BBaasshh's exit status is the exit sta- + tus of the last command executed in the script. If no commands are ex- + ecuted, the exit status is 0. An attempt is first made to open the file in the current directory, and, if no file is found, then the shell searches the directories in PPAATTHH for the script. IINNVVOOCCAATTIIOONN - A _l_o_g_i_n _s_h_e_l_l is one whose first character of argument zero is a --, or + A _l_o_g_i_n _s_h_e_l_l is one whose first character of argument zero is a --, or one started with the ----llooggiinn option. - An _i_n_t_e_r_a_c_t_i_v_e shell is one started without non-option arguments - (unless --ss is specified) and without the --cc option whose standard input + An _i_n_t_e_r_a_c_t_i_v_e shell is one started without non-option arguments (un- + less --ss is specified) and without the --cc option whose standard input and error are both connected to terminals (as determined by _i_s_a_t_t_y(3)), - or one started with the --ii option. PPSS11 is set and $$-- includes ii if - bbaasshh is interactive, allowing a shell script or a startup file to test + or one started with the --ii option. PPSS11 is set and $$-- includes ii if + bbaasshh is interactive, allowing a shell script or a startup file to test this state. - The following paragraphs describe how bbaasshh executes its startup files. - If any of the files exist but cannot be read, bbaasshh reports an error. - Tildes are expanded in filenames as described below under TTiillddee EExxppaann-- + The following paragraphs describe how bbaasshh executes its startup files. + If any of the files exist but cannot be read, bbaasshh reports an error. + Tildes are expanded in filenames as described below under TTiillddee EExxppaann-- ssiioonn in the EEXXPPAANNSSIIOONN section. - When bbaasshh is invoked as an interactive login shell, or as a non-inter- - active shell with the ----llooggiinn option, it first reads and executes com- - mands from the file _/_e_t_c_/_p_r_o_f_i_l_e, if that file exists. After reading + When bbaasshh is invoked as an interactive login shell, or as a non-inter- + active shell with the ----llooggiinn option, it first reads and executes com- + mands from the file _/_e_t_c_/_p_r_o_f_i_l_e, if that file exists. After reading that file, it looks for _~_/_._b_a_s_h___p_r_o_f_i_l_e, _~_/_._b_a_s_h___l_o_g_i_n, and _~_/_._p_r_o_f_i_l_e, - in that order, and reads and executes commands from the first one that - exists and is readable. The ----nnoopprrooffiillee option may be used when the + in that order, and reads and executes commands from the first one that + exists and is readable. The ----nnoopprrooffiillee option may be used when the shell is started to inhibit this behavior. When an interactive login shell exits, or a non-interactive login shell - executes the eexxiitt builtin command, bbaasshh reads and executes commands + executes the eexxiitt builtin command, bbaasshh reads and executes commands from the file _~_/_._b_a_s_h___l_o_g_o_u_t, if it exists. - When an interactive shell that is not a login shell is started, bbaasshh - reads and executes commands from _~_/_._b_a_s_h_r_c, if that file exists. This - may be inhibited by using the ----nnoorrcc option. The ----rrccffiillee _f_i_l_e option - will force bbaasshh to read and execute commands from _f_i_l_e instead of + When an interactive shell that is not a login shell is started, bbaasshh + reads and executes commands from _~_/_._b_a_s_h_r_c, if that file exists. This + may be inhibited by using the ----nnoorrcc option. The ----rrccffiillee _f_i_l_e option + will force bbaasshh to read and execute commands from _f_i_l_e instead of _~_/_._b_a_s_h_r_c. - When bbaasshh is started non-interactively, to run a shell script, for - example, it looks for the variable BBAASSHH__EENNVV in the environment, expands - its value if it appears there, and uses the expanded value as the name - of a file to read and execute. BBaasshh behaves as if the following com- + When bbaasshh is started non-interactively, to run a shell script, for ex- + ample, it looks for the variable BBAASSHH__EENNVV in the environment, expands + its value if it appears there, and uses the expanded value as the name + of a file to read and execute. BBaasshh behaves as if the following com- mand were executed: if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi - but the value of the PPAATTHH variable is not used to search for the file- + but the value of the PPAATTHH variable is not used to search for the file- name. - If bbaasshh is invoked with the name sshh, it tries to mimic the startup - behavior of historical versions of sshh as closely as possible, while - conforming to the POSIX standard as well. When invoked as an interac- - tive login shell, or a non-interactive shell with the ----llooggiinn option, - it first attempts to read and execute commands from _/_e_t_c_/_p_r_o_f_i_l_e and - _~_/_._p_r_o_f_i_l_e, in that order. The ----nnoopprrooffiillee option may be used to - inhibit this behavior. When invoked as an interactive shell with the - name sshh, bbaasshh looks for the variable EENNVV, expands its value if it is - defined, and uses the expanded value as the name of a file to read and + If bbaasshh is invoked with the name sshh, it tries to mimic the startup be- + havior of historical versions of sshh as closely as possible, while con- + forming to the POSIX standard as well. When invoked as an interactive + login shell, or a non-interactive shell with the ----llooggiinn option, it + first attempts to read and execute commands from _/_e_t_c_/_p_r_o_f_i_l_e and + _~_/_._p_r_o_f_i_l_e, in that order. The ----nnoopprrooffiillee option may be used to in- + hibit this behavior. When invoked as an interactive shell with the + name sshh, bbaasshh looks for the variable EENNVV, expands its value if it is + defined, and uses the expanded value as the name of a file to read and execute. Since a shell invoked as sshh does not attempt to read and exe- - cute commands from any other startup files, the ----rrccffiillee option has no - effect. A non-interactive shell invoked with the name sshh does not - attempt to read any other startup files. When invoked as sshh, bbaasshh - enters _p_o_s_i_x mode after the startup files are read. + cute commands from any other startup files, the ----rrccffiillee option has no + effect. A non-interactive shell invoked with the name sshh does not at- + tempt to read any other startup files. When invoked as sshh, bbaasshh enters + _p_o_s_i_x mode after the startup files are read. - When bbaasshh is started in _p_o_s_i_x mode, as with the ----ppoossiixx command line + When bbaasshh is started in _p_o_s_i_x mode, as with the ----ppoossiixx command line option, it follows the POSIX standard for startup files. In this mode, - interactive shells expand the EENNVV variable and commands are read and - executed from the file whose name is the expanded value. No other + interactive shells expand the EENNVV variable and commands are read and + executed from the file whose name is the expanded value. No other startup files are read. BBaasshh attempts to determine when it is being run with its standard input connected to a network connection, as when executed by the remote shell - daemon, usually _r_s_h_d, or the secure shell daemon _s_s_h_d. If bbaasshh deter- - mines it is being run in this fashion, it reads and executes commands - from _~_/_._b_a_s_h_r_c, if that file exists and is readable. It will not do - this if invoked as sshh. The ----nnoorrcc option may be used to inhibit this - behavior, and the ----rrccffiillee option may be used to force another file to - be read, but neither _r_s_h_d nor _s_s_h_d generally invoke the shell with + daemon, usually _r_s_h_d, or the secure shell daemon _s_s_h_d. If bbaasshh deter- + mines it is being run in this fashion, it reads and executes commands + from _~_/_._b_a_s_h_r_c, if that file exists and is readable. It will not do + this if invoked as sshh. The ----nnoorrcc option may be used to inhibit this + behavior, and the ----rrccffiillee option may be used to force another file to + be read, but neither _r_s_h_d nor _s_s_h_d generally invoke the shell with those options or allow them to be specified. If the shell is started with the effective user (group) id not equal to the real user (group) id, and the --pp option is not supplied, no startup files are read, shell functions are not inherited from the environment, - the SSHHEELLLLOOPPTTSS, BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they - appear in the environment, are ignored, and the effective user id is - set to the real user id. If the --pp option is supplied at invocation, - the startup behavior is the same, but the effective user id is not - reset. + the SSHHEELLLLOOPPTTSS, BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they ap- + pear in the environment, are ignored, and the effective user id is set + to the real user id. If the --pp option is supplied at invocation, the + startup behavior is the same, but the effective user id is not reset. DDEEFFIINNIITTIIOONNSS The following definitions are used throughout the rest of this docu- @@ -231,160 +229,162 @@ DDEEFFIINNIITTIIOONNSS RREESSEERRVVEEDD WWOORRDDSS _R_e_s_e_r_v_e_d _w_o_r_d_s are words that have a special meaning to the shell. The following words are recognized as reserved when unquoted and either the - first word of a simple command (see SSHHEELLLL GGRRAAMMMMAARR below) or the third - word of a ccaassee or ffoorr command: + first word of a command (see SSHHEELLLL GGRRAAMMMMAARR below), the third word of a + ccaassee or sseelleecctt command (only iinn is valid), or the third word of a ffoorr + command (only iinn and ddoo are valid): - !! ccaassee ccoopprroocc ddoo ddoonnee eelliiff eellssee eessaacc ffii ffoorr ffuunnccttiioonn iiff iinn sseelleecctt + !! ccaassee ccoopprroocc ddoo ddoonnee eelliiff eellssee eessaacc ffii ffoorr ffuunnccttiioonn iiff iinn sseelleecctt tthheenn uunnttiill wwhhiillee {{ }} ttiimmee [[[[ ]]]] SSHHEELLLL GGRRAAMMMMAARR SSiimmppllee CCoommmmaannddss - A _s_i_m_p_l_e _c_o_m_m_a_n_d is a sequence of optional variable assignments fol- - lowed by bbllaannkk-separated words and redirections, and terminated by a + A _s_i_m_p_l_e _c_o_m_m_a_n_d is a sequence of optional variable assignments fol- + lowed by bbllaannkk-separated words and redirections, and terminated by a _c_o_n_t_r_o_l _o_p_e_r_a_t_o_r. The first word specifies the command to be executed, - and is passed as argument zero. The remaining words are passed as - arguments to the invoked command. + and is passed as argument zero. The remaining words are passed as ar- + guments to the invoked command. - The return value of a _s_i_m_p_l_e _c_o_m_m_a_n_d is its exit status, or 128+_n if + The return value of a _s_i_m_p_l_e _c_o_m_m_a_n_d is its exit status, or 128+_n if the command is terminated by signal _n. PPiippeelliinneess - A _p_i_p_e_l_i_n_e is a sequence of one or more commands separated by one of + A _p_i_p_e_l_i_n_e is a sequence of one or more commands separated by one of the control operators || or ||&&. The format for a pipeline is: [ttiimmee [--pp]] [ ! ] _c_o_m_m_a_n_d [ [|||||&&] _c_o_m_m_a_n_d_2 ... ] - The standard output of _c_o_m_m_a_n_d is connected via a pipe to the standard - input of _c_o_m_m_a_n_d_2. This connection is performed before any redirec- + The standard output of _c_o_m_m_a_n_d is connected via a pipe to the standard + input of _c_o_m_m_a_n_d_2. This connection is performed before any redirec- tions specified by the command (see RREEDDIIRREECCTTIIOONN below). If ||&& is used, - _c_o_m_m_a_n_d's standard error, in addition to its standard output, is con- - nected to _c_o_m_m_a_n_d_2's standard input through the pipe; it is shorthand - for 22>>&&11 ||. This implicit redirection of the standard error to the - standard output is performed after any redirections specified by the + _c_o_m_m_a_n_d's standard error, in addition to its standard output, is con- + nected to _c_o_m_m_a_n_d_2's standard input through the pipe; it is shorthand + for 22>>&&11 ||. This implicit redirection of the standard error to the + standard output is performed after any redirections specified by the command. The return status of a pipeline is the exit status of the last command, - unless the ppiippeeffaaiill option is enabled. If ppiippeeffaaiill is enabled, the - pipeline's return status is the value of the last (rightmost) command - to exit with a non-zero status, or zero if all commands exit success- + unless the ppiippeeffaaiill option is enabled. If ppiippeeffaaiill is enabled, the + pipeline's return status is the value of the last (rightmost) command + to exit with a non-zero status, or zero if all commands exit success- fully. If the reserved word !! precedes a pipeline, the exit status of - that pipeline is the logical negation of the exit status as described - above. The shell waits for all commands in the pipeline to terminate + that pipeline is the logical negation of the exit status as described + above. The shell waits for all commands in the pipeline to terminate before returning a value. - If the ttiimmee reserved word precedes a pipeline, the elapsed as well as - user and system time consumed by its execution are reported when the - pipeline terminates. The --pp option changes the output format to that - specified by POSIX. When the shell is in _p_o_s_i_x _m_o_d_e, it does not rec- - ognize ttiimmee as a reserved word if the next token begins with a `-'. - The TTIIMMEEFFOORRMMAATT variable may be set to a format string that specifies - how the timing information should be displayed; see the description of + If the ttiimmee reserved word precedes a pipeline, the elapsed as well as + user and system time consumed by its execution are reported when the + pipeline terminates. The --pp option changes the output format to that + specified by POSIX. When the shell is in _p_o_s_i_x _m_o_d_e, it does not rec- + ognize ttiimmee as a reserved word if the next token begins with a `-'. + The TTIIMMEEFFOORRMMAATT variable may be set to a format string that specifies + how the timing information should be displayed; see the description of TTIIMMEEFFOORRMMAATT under SShheellll VVaarriiaabblleess below. When the shell is in _p_o_s_i_x _m_o_d_e, ttiimmee may be followed by a newline. In - this case, the shell displays the total user and system time consumed - by the shell and its children. The TTIIMMEEFFOORRMMAATT variable may be used to + this case, the shell displays the total user and system time consumed + by the shell and its children. The TTIIMMEEFFOORRMMAATT variable may be used to specify the format of the time information. - Each command in a pipeline is executed as a separate process (i.e., in - a subshell). See CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENNTT for a description of a - subshell environment. If the llaassttppiippee option is enabled using the + Each command in a pipeline is executed as a separate process (i.e., in + a subshell). See CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENNTT for a description of a + subshell environment. If the llaassttppiippee option is enabled using the sshhoopptt builtin (see the description of sshhoopptt below), the last element of a pipeline may be run by the shell process. LLiissttss - A _l_i_s_t is a sequence of one or more pipelines separated by one of the + A _l_i_s_t is a sequence of one or more pipelines separated by one of the operators ;;, &&, &&&&, or ||||, and optionally terminated by one of ;;, &&, or <<nneewwlliinnee>>. Of these list operators, &&&& and |||| have equal precedence, followed by ;; and &&, which have equal precedence. - A sequence of one or more newlines may appear in a _l_i_s_t instead of a + A sequence of one or more newlines may appear in a _l_i_s_t instead of a semicolon to delimit commands. - If a command is terminated by the control operator &&, the shell exe- - cutes the command in the _b_a_c_k_g_r_o_u_n_d in a subshell. The shell does not - wait for the command to finish, and the return status is 0. These are - referred to as _a_s_y_n_c_h_r_o_n_o_u_s commands. Commands separated by a ;; are + If a command is terminated by the control operator &&, the shell exe- + cutes the command in the _b_a_c_k_g_r_o_u_n_d in a subshell. The shell does not + wait for the command to finish, and the return status is 0. These are + referred to as _a_s_y_n_c_h_r_o_n_o_u_s commands. Commands separated by a ;; are executed sequentially; the shell waits for each command to terminate in - turn. The return status is the exit status of the last command exe- + turn. The return status is the exit status of the last command exe- cuted. - AND and OR lists are sequences of one or more pipelines separated by - the &&&& and |||| control operators, respectively. AND and OR lists are + AND and OR lists are sequences of one or more pipelines separated by + the &&&& and |||| control operators, respectively. AND and OR lists are executed with left associativity. An AND list has the form _c_o_m_m_a_n_d_1 &&&& _c_o_m_m_a_n_d_2 - _c_o_m_m_a_n_d_2 is executed if, and only if, _c_o_m_m_a_n_d_1 returns an exit status + _c_o_m_m_a_n_d_2 is executed if, and only if, _c_o_m_m_a_n_d_1 returns an exit status of zero (success). An OR list has the form _c_o_m_m_a_n_d_1 |||| _c_o_m_m_a_n_d_2 - _c_o_m_m_a_n_d_2 is executed if, and only if, _c_o_m_m_a_n_d_1 returns a non-zero exit - status. The return status of AND and OR lists is the exit status of + _c_o_m_m_a_n_d_2 is executed if, and only if, _c_o_m_m_a_n_d_1 returns a non-zero exit + status. The return status of AND and OR lists is the exit status of the last command executed in the list. CCoommppoouunndd CCoommmmaannddss - A _c_o_m_p_o_u_n_d _c_o_m_m_a_n_d is one of the following. In most cases a _l_i_s_t in a - command's description may be separated from the rest of the command by - one or more newlines, and may be followed by a newline in place of a + A _c_o_m_p_o_u_n_d _c_o_m_m_a_n_d is one of the following. In most cases a _l_i_s_t in a + command's description may be separated from the rest of the command by + one or more newlines, and may be followed by a newline in place of a semicolon. - (_l_i_s_t) _l_i_s_t is executed in a subshell environment (see CCOOMMMMAANNDD EEXXEECCUU-- - TTIIOONN EENNVVIIRROONNMMEENNTT below). Variable assignments and builtin com- - mands that affect the shell's environment do not remain in - effect after the command completes. The return status is the - exit status of _l_i_s_t. + (_l_i_s_t) _l_i_s_t is executed in a subshell environment (see CCOOMMMMAANNDD EEXXEECCUU-- + TTIIOONN EENNVVIIRROONNMMEENNTT below). Variable assignments and builtin com- + mands that affect the shell's environment do not remain in ef- + fect after the command completes. The return status is the exit + status of _l_i_s_t. { _l_i_s_t; } - _l_i_s_t is simply executed in the current shell environment. _l_i_s_t - must be terminated with a newline or semicolon. This is known - as a _g_r_o_u_p _c_o_m_m_a_n_d. The return status is the exit status of - _l_i_s_t. Note that unlike the metacharacters (( and )), {{ and }} are + _l_i_s_t is simply executed in the current shell environment. _l_i_s_t + must be terminated with a newline or semicolon. This is known + as a _g_r_o_u_p _c_o_m_m_a_n_d. The return status is the exit status of + _l_i_s_t. Note that unlike the metacharacters (( and )), {{ and }} are _r_e_s_e_r_v_e_d _w_o_r_d_s and must occur where a reserved word is permitted - to be recognized. Since they do not cause a word break, they - must be separated from _l_i_s_t by whitespace or another shell + to be recognized. Since they do not cause a word break, they + must be separated from _l_i_s_t by whitespace or another shell metacharacter. ((_e_x_p_r_e_s_s_i_o_n)) - The _e_x_p_r_e_s_s_i_o_n is evaluated according to the rules described - below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. If the value of the expres- - sion is non-zero, the return status is 0; otherwise the return - status is 1. This is exactly equivalent to lleett ""_e_x_p_r_e_s_s_i_o_n"". + The _e_x_p_r_e_s_s_i_o_n is evaluated according to the rules described be- + low under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. If the value of the expression + is non-zero, the return status is 0; otherwise the return status + is 1. This is exactly equivalent to lleett ""_e_x_p_r_e_s_s_i_o_n"". [[[[ _e_x_p_r_e_s_s_i_o_n ]]]] - Return a status of 0 or 1 depending on the evaluation of the - conditional expression _e_x_p_r_e_s_s_i_o_n. Expressions are composed of - the primaries described below under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS. - Word splitting and pathname expansion are not performed on the - words between the [[[[ and ]]]]; tilde expansion, parameter and - variable expansion, arithmetic expansion, command substitution, - process substitution, and quote removal are performed. Condi- + Return a status of 0 or 1 depending on the evaluation of the + conditional expression _e_x_p_r_e_s_s_i_o_n. Expressions are composed of + the primaries described below under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS. + Word splitting and pathname expansion are not performed on the + words between the [[[[ and ]]]]; tilde expansion, parameter and + variable expansion, arithmetic expansion, command substitution, + process substitution, and quote removal are performed. Condi- tional operators such as --ff must be unquoted to be recognized as primaries. - When used with [[[[, the << and >> operators sort lexicographically + When used with [[[[, the << and >> operators sort lexicographically using the current locale. - When the ==== and !!== operators are used, the string to the right + When the ==== and !!== operators are used, the string to the right of the operator is considered a pattern and matched according to the rules described below under PPaatttteerrnn MMaattcchhiinngg, as if the eexxtt-- gglloobb shell option were enabled. The == operator is equivalent to - ====. If the nnooccaasseemmaattcchh shell option is enabled, the match is - performed without regard to the case of alphabetic characters. - The return value is 0 if the string matches (====) or does not - match (!!==) the pattern, and 1 otherwise. Any part of the pat- - tern may be quoted to force the quoted portion to be matched as + ====. If the nnooccaasseemmaattcchh shell option is enabled, the match is + performed without regard to the case of alphabetic characters. + The return value is 0 if the string matches (====) or does not + match (!!==) the pattern, and 1 otherwise. Any part of the pat- + tern may be quoted to force the quoted portion to be matched as a string. - An additional binary operator, ==~~, is available, with the same - precedence as ==== and !!==. When it is used, the string to the - right of the operator is considered a POSIX extended regular - expression and matched accordingly (as in _r_e_g_e_x(3)). The return + An additional binary operator, ==~~, is available, with the same + precedence as ==== and !!==. When it is used, the string to the + right of the operator is considered a POSIX extended regular ex- + pression and matched accordingly (using the POSIX _r_e_g_c_o_m_p and + _r_e_g_e_x_e_c interfaces usually described in _r_e_g_e_x(3)). The return value is 0 if the string matches the pattern, and 1 otherwise. If the regular expression is syntactically incorrect, the condi- tional expression's return value is 2. If the nnooccaasseemmaattcchh shell @@ -392,14 +392,20 @@ SSHHEELLLL GGRRAAMMMMAARR case of alphabetic characters. Any part of the pattern may be quoted to force the quoted portion to be matched as a string. Bracket expressions in regular expressions must be treated care- - fully, since normal quoting characters lose their meanings - between brackets. If the pattern is stored in a shell variable, + fully, since normal quoting characters lose their meanings be- + tween brackets. If the pattern is stored in a shell variable, quoting the variable expansion forces the entire pattern to be - matched as a string. Substrings matched by parenthesized subex- - pressions within the regular expression are saved in the array - variable BBAASSHH__RREEMMAATTCCHH. The element of BBAASSHH__RREEMMAATTCCHH with index 0 - is the portion of the string matching the entire regular expres- - sion. The element of BBAASSHH__RREEMMAATTCCHH with index _n is the portion + matched as a string. + + The pattern will match if it matches any part of the string. + Anchor the pattern using the ^^ and $$ regular expression opera- + tors to force it to match the entire string. The array variable + BBAASSHH__RREEMMAATTCCHH records which parts of the string matched the pat- + tern. The element of BBAASSHH__RREEMMAATTCCHH with index 0 contains the + portion of the string matching the entire regular expression. + Substrings matched by parenthesized subexpressions within the + regular expression are saved in the remaining BBAASSHH__RREEMMAATTCCHH in- + dices. The element of BBAASSHH__RREEMMAATTCCHH with index _n is the portion of the string matching the _nth parenthesized subexpression. Expressions may be combined using the following operators, @@ -423,8 +429,8 @@ SSHHEELLLL GGRRAAMMMMAARR The list of words following iinn is expanded, generating a list of items. The variable _n_a_m_e is set to each element of this list in turn, and _l_i_s_t is executed each time. If the iinn _w_o_r_d is omit- - ted, the ffoorr command executes _l_i_s_t once for each positional - parameter that is set (see PPAARRAAMMEETTEERRSS below). The return status + ted, the ffoorr command executes _l_i_s_t once for each positional pa- + rameter that is set (see PPAARRAAMMEETTEERRSS below). The return status is the exit status of the last command that executes. If the expansion of the items following iinn results in an empty list, no commands are executed, and the return status is 0. @@ -442,19 +448,19 @@ SSHHEELLLL GGRRAAMMMMAARR sseelleecctt _n_a_m_e [ iinn _w_o_r_d ] ; ddoo _l_i_s_t ; ddoonnee The list of words following iinn is expanded, generating a list of - items. The set of expanded words is printed on the standard - error, each preceded by a number. If the iinn _w_o_r_d is omitted, - the positional parameters are printed (see PPAARRAAMMEETTEERRSS below). - The PPSS33 prompt is then displayed and a line read from the stan- - dard input. If the line consists of a number corresponding to - one of the displayed words, then the value of _n_a_m_e is set to - that word. If the line is empty, the words and prompt are dis- - played again. If EOF is read, the command completes. Any other - value read causes _n_a_m_e to be set to null. The line read is - saved in the variable RREEPPLLYY. The _l_i_s_t is executed after each - selection until a bbrreeaakk command is executed. The exit status of - sseelleecctt is the exit status of the last command executed in _l_i_s_t, - or zero if no commands were executed. + items. The set of expanded words is printed on the standard er- + ror, each preceded by a number. If the iinn _w_o_r_d is omitted, the + positional parameters are printed (see PPAARRAAMMEETTEERRSS below). The + PPSS33 prompt is then displayed and a line read from the standard + input. If the line consists of a number corresponding to one of + the displayed words, then the value of _n_a_m_e is set to that word. + If the line is empty, the words and prompt are displayed again. + If EOF is read, the command completes. Any other value read + causes _n_a_m_e to be set to null. The line read is saved in the + variable RREEPPLLYY. The _l_i_s_t is executed after each selection until + a bbrreeaakk command is executed. The exit status of sseelleecctt is the + exit status of the last command executed in _l_i_s_t, or zero if no + commands were executed. ccaassee _w_o_r_d iinn [ [(] _p_a_t_t_e_r_n [ || _p_a_t_t_e_r_n ] ... ) _l_i_s_t ;; ] ... eessaacc A ccaassee command first expands _w_o_r_d, and tries to match it against @@ -473,29 +479,29 @@ SSHHEELLLL GGRRAAMMMMAARR _l_i_s_t associated with the next set of patterns. Using ;;;;&& in place of ;;;; causes the shell to test the next pattern list in the statement, if any, and execute any associated _l_i_s_t on a suc- - cessful match. The exit status is zero if no pattern matches. - Otherwise, it is the exit status of the last command executed in - _l_i_s_t. + cessful match, continuing the case statement execution as if the + pattern list had not matched. The exit status is zero if no + pattern matches. Otherwise, it is the exit status of the last + command executed in _l_i_s_t. iiff _l_i_s_t; tthheenn _l_i_s_t; [ eelliiff _l_i_s_t; tthheenn _l_i_s_t; ] ... [ eellssee _l_i_s_t; ] ffii - The iiff _l_i_s_t is executed. If its exit status is zero, the tthheenn - _l_i_s_t is executed. Otherwise, each eelliiff _l_i_s_t is executed in - turn, and if its exit status is zero, the corresponding tthheenn + The iiff _l_i_s_t is executed. If its exit status is zero, the tthheenn + _l_i_s_t is executed. Otherwise, each eelliiff _l_i_s_t is executed in + turn, and if its exit status is zero, the corresponding tthheenn _l_i_s_t is executed and the command completes. Otherwise, the eellssee - _l_i_s_t is executed, if present. The exit status is the exit sta- + _l_i_s_t is executed, if present. The exit status is the exit sta- tus of the last command executed, or zero if no condition tested true. wwhhiillee _l_i_s_t_-_1; ddoo _l_i_s_t_-_2; ddoonnee uunnttiill _l_i_s_t_-_1; ddoo _l_i_s_t_-_2; ddoonnee - The wwhhiillee command continuously executes the list _l_i_s_t_-_2 as long + The wwhhiillee command continuously executes the list _l_i_s_t_-_2 as long as the last command in the list _l_i_s_t_-_1 returns an exit status of - zero. The uunnttiill command is identical to the wwhhiillee command, - except that the test is negated: _l_i_s_t_-_2 is executed as long as - the last command in _l_i_s_t_-_1 returns a non-zero exit status. The - exit status of the wwhhiillee and uunnttiill commands is the exit status - of the last command executed in _l_i_s_t_-_2, or zero if none was exe- - cuted. + zero. The uunnttiill command is identical to the wwhhiillee command, ex- + cept that the test is negated: _l_i_s_t_-_2 is executed as long as the + last command in _l_i_s_t_-_1 returns a non-zero exit status. The exit + status of the wwhhiillee and uunnttiill commands is the exit status of the + last command executed in _l_i_s_t_-_2, or zero if none was executed. CCoopprroocceesssseess A _c_o_p_r_o_c_e_s_s is a shell command preceded by the ccoopprroocc reserved word. A @@ -507,24 +513,24 @@ SSHHEELLLL GGRRAAMMMMAARR ccoopprroocc [_N_A_M_E] _c_o_m_m_a_n_d [_r_e_d_i_r_e_c_t_i_o_n_s] - This creates a coprocess named _N_A_M_E. If _N_A_M_E is not supplied, the - default name is CCOOPPRROOCC. _N_A_M_E must not be supplied if _c_o_m_m_a_n_d is a _s_i_m_- - _p_l_e _c_o_m_m_a_n_d (see above); otherwise, it is interpreted as the first word - of the simple command. When the coprocess is executed, the shell cre- - ates an array variable (see AArrrraayyss below) named _N_A_M_E in the context of - the executing shell. The standard output of _c_o_m_m_a_n_d is connected via a - pipe to a file descriptor in the executing shell, and that file - descriptor is assigned to _N_A_M_E[0]. The standard input of _c_o_m_m_a_n_d is - connected via a pipe to a file descriptor in the executing shell, and - that file descriptor is assigned to _N_A_M_E[1]. This pipe is established - before any redirections specified by the command (see RREEDDIIRREECCTTIIOONN - below). The file descriptors can be utilized as arguments to shell - commands and redirections using standard word expansions. Other than - those created to execute command and process substitutions, the file - descriptors are not available in subshells. The process ID of the - shell spawned to execute the coprocess is available as the value of the - variable _N_A_M_E_PID. The wwaaiitt builtin command may be used to wait for - the coprocess to terminate. + This creates a coprocess named _N_A_M_E. If _N_A_M_E is not supplied, the de- + fault name is CCOOPPRROOCC. _N_A_M_E must not be supplied if _c_o_m_m_a_n_d is a _s_i_m_p_l_e + _c_o_m_m_a_n_d (see above); otherwise, it is interpreted as the first word of + the simple command. When the coprocess is executed, the shell creates + an array variable (see AArrrraayyss below) named _N_A_M_E in the context of the + executing shell. The standard output of _c_o_m_m_a_n_d is connected via a + pipe to a file descriptor in the executing shell, and that file de- + scriptor is assigned to _N_A_M_E[0]. The standard input of _c_o_m_m_a_n_d is con- + nected via a pipe to a file descriptor in the executing shell, and that + file descriptor is assigned to _N_A_M_E[1]. This pipe is established be- + fore any redirections specified by the command (see RREEDDIIRREECCTTIIOONN below). + The file descriptors can be utilized as arguments to shell commands and + redirections using standard word expansions. Other than those created + to execute command and process substitutions, the file descriptors are + not available in subshells. The process ID of the shell spawned to ex- + ecute the coprocess is available as the value of the variable _N_A_M_E_PID. + The wwaaiitt builtin command may be used to wait for the coprocess to ter- + minate. Since the coprocess is created as an asynchronous command, the ccoopprroocc command always returns success. The return status of a coprocess is @@ -535,9 +541,9 @@ SSHHEELLLL GGRRAAMMMMAARR executes a compound command with a new set of positional parameters. Shell functions are declared as follows: - _n_a_m_e () _c_o_m_p_o_u_n_d_-_c_o_m_m_a_n_d [_r_e_d_i_r_e_c_t_i_o_n] - ffuunnccttiioonn _n_a_m_e [()] _c_o_m_p_o_u_n_d_-_c_o_m_m_a_n_d [_r_e_d_i_r_e_c_t_i_o_n] - This defines a function named _n_a_m_e. The reserved word ffuunnccttiioonn + _f_n_a_m_e () _c_o_m_p_o_u_n_d_-_c_o_m_m_a_n_d [_r_e_d_i_r_e_c_t_i_o_n] + ffuunnccttiioonn _f_n_a_m_e [()] _c_o_m_p_o_u_n_d_-_c_o_m_m_a_n_d [_r_e_d_i_r_e_c_t_i_o_n] + This defines a function named _f_n_a_m_e. The reserved word ffuunnccttiioonn is optional. If the ffuunnccttiioonn reserved word is supplied, the parentheses are optional. The _b_o_d_y of the function is the com- pound command _c_o_m_p_o_u_n_d_-_c_o_m_m_a_n_d (see CCoommppoouunndd CCoommmmaannddss above). @@ -545,9 +551,11 @@ SSHHEELLLL GGRRAAMMMMAARR may be any command listed under CCoommppoouunndd CCoommmmaannddss above, with one exception: If the ffuunnccttiioonn reserved word is used, but the parentheses are not supplied, the braces are required. _c_o_m_- - _p_o_u_n_d_-_c_o_m_m_a_n_d is executed whenever _n_a_m_e is specified as the name - of a simple command. When in _p_o_s_i_x _m_o_d_e, _n_a_m_e may not be the - name of one of the POSIX _s_p_e_c_i_a_l _b_u_i_l_t_i_n_s. Any redirections + _p_o_u_n_d_-_c_o_m_m_a_n_d is executed whenever _f_n_a_m_e is specified as the + name of a simple command. When in _p_o_s_i_x _m_o_d_e, _f_n_a_m_e must be a + valid shell _n_a_m_e and may not be the name of one of the POSIX + _s_p_e_c_i_a_l _b_u_i_l_t_i_n_s. In default mode, a function name can be any + unquoted shell word that does not contain $$. Any redirections (see RREEDDIIRREECCTTIIOONN below) specified when a function is defined are performed when the function is executed. The exit status of a function definition is zero unless a syntax error occurs or a @@ -582,9 +590,9 @@ QQUUOOTTIINNGG A non-quoted backslash (\\) is the _e_s_c_a_p_e _c_h_a_r_a_c_t_e_r. It preserves the literal value of the next character that follows, with the exception of - <newline>. If a \\<newline> pair appears, and the backslash is not - itself quoted, the \\<newline> is treated as a line continuation (that - is, it is removed from the input stream and effectively ignored). + <newline>. If a \\<newline> pair appears, and the backslash is not it- + self quoted, the \\<newline> is treated as a line continuation (that is, + it is removed from the input stream and effectively ignored). Enclosing characters in single quotes preserves the literal value of each character within the quotes. A single quote may not occur between @@ -637,215 +645,219 @@ QQUUOOTTIINNGG been present. A double-quoted string preceded by a dollar sign ($$"_s_t_r_i_n_g") will cause - the string to be translated according to the current locale. If the - current locale is CC or PPOOSSIIXX, the dollar sign is ignored. If the - string is translated and replaced, the replacement is double-quoted. + the string to be translated according to the current locale. The _g_e_t_- + _t_e_x_t infrastructure performs the message catalog lookup and transla- + tion, using the LLCC__MMEESSSSAAGGEESS and TTEEXXTTDDOOMMAAIINN shell variables. If the + current locale is CC or PPOOSSIIXX, or if there are no translations avail- + able, the dollar sign is ignored. If the string is translated and re- + placed, the replacement is double-quoted. PPAARRAAMMEETTEERRSS - A _p_a_r_a_m_e_t_e_r is an entity that stores values. It can be a _n_a_m_e, a num- + A _p_a_r_a_m_e_t_e_r is an entity that stores values. It can be a _n_a_m_e, a num- ber, or one of the special characters listed below under SSppeecciiaall PPaarraamm-- - eetteerrss. A _v_a_r_i_a_b_l_e is a parameter denoted by a _n_a_m_e. A variable has a - _v_a_l_u_e and zero or more _a_t_t_r_i_b_u_t_e_s. Attributes are assigned using the + eetteerrss. A _v_a_r_i_a_b_l_e is a parameter denoted by a _n_a_m_e. A variable has a + _v_a_l_u_e and zero or more _a_t_t_r_i_b_u_t_e_s. Attributes are assigned using the ddeeccllaarree builtin command (see ddeeccllaarree below in SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS). A parameter is set if it has been assigned a value. The null string is - a valid value. Once a variable is set, it may be unset only by using + a valid value. Once a variable is set, it may be unset only by using the uunnsseett builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). A _v_a_r_i_a_b_l_e may be assigned to by a statement of the form _n_a_m_e=[_v_a_l_u_e] - If _v_a_l_u_e is not given, the variable is assigned the null string. All - _v_a_l_u_e_s undergo tilde expansion, parameter and variable expansion, com- - mand substitution, arithmetic expansion, and quote removal (see EEXXPPAANN-- + If _v_a_l_u_e is not given, the variable is assigned the null string. All + _v_a_l_u_e_s undergo tilde expansion, parameter and variable expansion, com- + mand substitution, arithmetic expansion, and quote removal (see EEXXPPAANN-- SSIIOONN below). If the variable has its iinntteeggeerr attribute set, then _v_a_l_u_e is evaluated as an arithmetic expression even if the $((...)) expansion - is not used (see AArriitthhmmeettiicc EExxppaannssiioonn below). Word splitting is not - performed, with the exception of ""$$@@"" as explained below under SSppeecciiaall - PPaarraammeetteerrss. Pathname expansion is not performed. Assignment state- - ments may also appear as arguments to the aalliiaass, ddeeccllaarree, ttyyppeesseett, - eexxppoorrtt, rreeaaddoonnllyy, and llooccaall builtin commands (_d_e_c_l_a_r_a_t_i_o_n commands). + is not used (see AArriitthhmmeettiicc EExxppaannssiioonn below). Word splitting is not + performed, with the exception of ""$$@@"" as explained below under SSppeecciiaall + PPaarraammeetteerrss. Pathname expansion is not performed. Assignment state- + ments may also appear as arguments to the aalliiaass, ddeeccllaarree, ttyyppeesseett, eexx-- + ppoorrtt, rreeaaddoonnllyy, and llooccaall builtin commands (_d_e_c_l_a_r_a_t_i_o_n commands). When in _p_o_s_i_x _m_o_d_e, these builtins may appear in a command after one or - more instances of the ccoommmmaanndd builtin and retain these assignment + more instances of the ccoommmmaanndd builtin and retain these assignment statement properties. - In the context where an assignment statement is assigning a value to a + In the context where an assignment statement is assigning a value to a shell variable or array index, the += operator can be used to append to - or add to the variable's previous value. This includes arguments to - builtin commands such as ddeeccllaarree that accept assignment statements + or add to the variable's previous value. This includes arguments to + builtin commands such as ddeeccllaarree that accept assignment statements (_d_e_c_l_a_r_a_t_i_o_n commands). When += is applied to a variable for which the - _i_n_t_e_g_e_r attribute has been set, _v_a_l_u_e is evaluated as an arithmetic - expression and added to the variable's current value, which is also - evaluated. When += is applied to an array variable using compound - assignment (see AArrrraayyss below), the variable's value is not unset (as it - is when using =), and new values are appended to the array beginning at - one greater than the array's maximum index (for indexed arrays) or - added as additional key-value pairs in an associative array. When - applied to a string-valued variable, _v_a_l_u_e is expanded and appended to + _i_n_t_e_g_e_r attribute has been set, _v_a_l_u_e is evaluated as an arithmetic ex- + pression and added to the variable's current value, which is also eval- + uated. When += is applied to an array variable using compound assign- + ment (see AArrrraayyss below), the variable's value is not unset (as it is + when using =), and new values are appended to the array beginning at + one greater than the array's maximum index (for indexed arrays) or + added as additional key-value pairs in an associative array. When ap- + plied to a string-valued variable, _v_a_l_u_e is expanded and appended to the variable's value. A variable can be assigned the _n_a_m_e_r_e_f attribute using the --nn option to - the ddeeccllaarree or llooccaall builtin commands (see the descriptions of ddeeccllaarree - and llooccaall below) to create a _n_a_m_e_r_e_f, or a reference to another vari- - able. This allows variables to be manipulated indirectly. Whenever - the nameref variable is referenced, assigned to, unset, or has its - attributes modified (other than using or changing the _n_a_m_e_r_e_f attribute - itself), the operation is actually performed on the variable specified - by the nameref variable's value. A nameref is commonly used within + the ddeeccllaarree or llooccaall builtin commands (see the descriptions of ddeeccllaarree + and llooccaall below) to create a _n_a_m_e_r_e_f, or a reference to another vari- + able. This allows variables to be manipulated indirectly. Whenever + the nameref variable is referenced, assigned to, unset, or has its at- + tributes modified (other than using or changing the _n_a_m_e_r_e_f attribute + itself), the operation is actually performed on the variable specified + by the nameref variable's value. A nameref is commonly used within shell functions to refer to a variable whose name is passed as an argu- - ment to the function. For instance, if a variable name is passed to a + ment to the function. For instance, if a variable name is passed to a shell function as its first argument, running declare -n ref=$1 - inside the function creates a nameref variable rreeff whose value is the + inside the function creates a nameref variable rreeff whose value is the variable name passed as the first argument. References and assignments - to rreeff, and changes to its attributes, are treated as references, - assignments, and attribute modifications to the variable whose name was - passed as $$11. If the control variable in a ffoorr loop has the nameref - attribute, the list of words can be a list of shell variables, and a - name reference will be established for each word in the list, in turn, + to rreeff, and changes to its attributes, are treated as references, as- + signments, and attribute modifications to the variable whose name was + passed as $$11. If the control variable in a ffoorr loop has the nameref + attribute, the list of words can be a list of shell variables, and a + name reference will be established for each word in the list, in turn, when the loop is executed. Array variables cannot be given the nnaammeerreeff - attribute. However, nameref variables can reference array variables - and subscripted array variables. Namerefs can be unset using the --nn - option to the uunnsseett builtin. Otherwise, if uunnsseett is executed with the - name of a nameref variable as an argument, the variable referenced by + attribute. However, nameref variables can reference array variables + and subscripted array variables. Namerefs can be unset using the --nn + option to the uunnsseett builtin. Otherwise, if uunnsseett is executed with the + name of a nameref variable as an argument, the variable referenced by the nameref variable will be unset. PPoossiittiioonnaall PPaarraammeetteerrss - A _p_o_s_i_t_i_o_n_a_l _p_a_r_a_m_e_t_e_r is a parameter denoted by one or more digits, + A _p_o_s_i_t_i_o_n_a_l _p_a_r_a_m_e_t_e_r is a parameter denoted by one or more digits, other than the single digit 0. Positional parameters are assigned from - the shell's arguments when it is invoked, and may be reassigned using - the sseett builtin command. Positional parameters may not be assigned to - with assignment statements. The positional parameters are temporarily + the shell's arguments when it is invoked, and may be reassigned using + the sseett builtin command. Positional parameters may not be assigned to + with assignment statements. The positional parameters are temporarily replaced when a shell function is executed (see FFUUNNCCTTIIOONNSS below). - When a positional parameter consisting of more than a single digit is + When a positional parameter consisting of more than a single digit is expanded, it must be enclosed in braces (see EEXXPPAANNSSIIOONN below). SSppeecciiaall PPaarraammeetteerrss - The shell treats several parameters specially. These parameters may + The shell treats several parameters specially. These parameters may only be referenced; assignment to them is not allowed. - ** Expands to the positional parameters, starting from one. When - the expansion is not within double quotes, each positional - parameter expands to a separate word. In contexts where it is + ** Expands to the positional parameters, starting from one. When + the expansion is not within double quotes, each positional pa- + rameter expands to a separate word. In contexts where it is performed, those words are subject to further word splitting and - pathname expansion. When the expansion occurs within double - quotes, it expands to a single word with the value of each - parameter separated by the first character of the IIFFSS special - variable. That is, "$$**" is equivalent to "$$11_c$$22_c......", where _c + pathname expansion. When the expansion occurs within double + quotes, it expands to a single word with the value of each pa- + rameter separated by the first character of the IIFFSS special + variable. That is, "$$**" is equivalent to "$$11_c$$22_c......", where _c is the first character of the value of the IIFFSS variable. If IIFFSS - is unset, the parameters are separated by spaces. If IIFFSS is + is unset, the parameters are separated by spaces. If IIFFSS is null, the parameters are joined without intervening separators. - @@ Expands to the positional parameters, starting from one. In - contexts where word splitting is performed, this expands each - positional parameter to a separate word; if not within double - quotes, these words are subject to word splitting. In contexts - where word splitting is not performed, this expands to a single - word with each positional parameter separated by a space. When - the expansion occurs within double quotes, each parameter - expands to a separate word. That is, "$$@@" is equivalent to "$$11" - "$$22" ... If the double-quoted expansion occurs within a word, - the expansion of the first parameter is joined with the begin- - ning part of the original word, and the expansion of the last - parameter is joined with the last part of the original word. - When there are no positional parameters, "$$@@" and $$@@ expand to + @@ Expands to the positional parameters, starting from one. In + contexts where word splitting is performed, this expands each + positional parameter to a separate word; if not within double + quotes, these words are subject to word splitting. In contexts + where word splitting is not performed, this expands to a single + word with each positional parameter separated by a space. When + the expansion occurs within double quotes, each parameter ex- + pands to a separate word. That is, "$$@@" is equivalent to "$$11" + "$$22" ... If the double-quoted expansion occurs within a word, + the expansion of the first parameter is joined with the begin- + ning part of the original word, and the expansion of the last + parameter is joined with the last part of the original word. + When there are no positional parameters, "$$@@" and $$@@ expand to nothing (i.e., they are removed). ## Expands to the number of positional parameters in decimal. - ?? Expands to the exit status of the most recently executed fore- + ?? Expands to the exit status of the most recently executed fore- ground pipeline. - -- Expands to the current option flags as specified upon invoca- - tion, by the sseett builtin command, or those set by the shell - itself (such as the --ii option). - $$ Expands to the process ID of the shell. In a () subshell, it - expands to the process ID of the current shell, not the sub- + -- Expands to the current option flags as specified upon invoca- + tion, by the sseett builtin command, or those set by the shell it- + self (such as the --ii option). + $$ Expands to the process ID of the shell. In a () subshell, it + expands to the process ID of the current shell, not the sub- shell. - !! Expands to the process ID of the job most recently placed into - the background, whether executed as an asynchronous command or + !! Expands to the process ID of the job most recently placed into + the background, whether executed as an asynchronous command or using the bbgg builtin (see JJOOBB CCOONNTTRROOLL below). - 00 Expands to the name of the shell or shell script. This is set + 00 Expands to the name of the shell or shell script. This is set at shell initialization. If bbaasshh is invoked with a file of com- - mands, $$00 is set to the name of that file. If bbaasshh is started - with the --cc option, then $$00 is set to the first argument after - the string to be executed, if one is present. Otherwise, it is - set to the filename used to invoke bbaasshh, as given by argument + mands, $$00 is set to the name of that file. If bbaasshh is started + with the --cc option, then $$00 is set to the first argument after + the string to be executed, if one is present. Otherwise, it is + set to the filename used to invoke bbaasshh, as given by argument zero. - __ At shell startup, set to the absolute pathname used to invoke - the shell or shell script being executed as passed in the envi- - ronment or argument list. Subsequently, expands to the last - argument to the previous simple command executed in the fore- - ground, after expansion. Also set to the full pathname used to - invoke each command executed and placed in the environment - exported to that command. When checking mail, this parameter - holds the name of the mail file currently being checked. SShheellll VVaarriiaabblleess The following variables are set by the shell: - BBAASSHH Expands to the full filename used to invoke this instance of + __ At shell startup, set to the pathname used to invoke the shell + or shell script being executed as passed in the environment or + argument list. Subsequently, expands to the last argument to + the previous simple command executed in the foreground, after + expansion. Also set to the full pathname used to invoke each + command executed and placed in the environment exported to that + command. When checking mail, this parameter holds the name of + the mail file currently being checked. + BBAASSHH Expands to the full filename used to invoke this instance of bbaasshh. BBAASSHHOOPPTTSS - A colon-separated list of enabled shell options. Each word in - the list is a valid argument for the --ss option to the sshhoopptt + A colon-separated list of enabled shell options. Each word in + the list is a valid argument for the --ss option to the sshhoopptt builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). The options - appearing in BBAASSHHOOPPTTSS are those reported as _o_n by sshhoopptt. If - this variable is in the environment when bbaasshh starts up, each - shell option in the list will be enabled before reading any + appearing in BBAASSHHOOPPTTSS are those reported as _o_n by sshhoopptt. If + this variable is in the environment when bbaasshh starts up, each + shell option in the list will be enabled before reading any startup files. This variable is read-only. BBAASSHHPPIIDD - Expands to the process ID of the current bbaasshh process. This - differs from $$$$ under certain circumstances, such as subshells - that do not require bbaasshh to be re-initialized. Assignments to - BBAASSHHPPIIDD have no effect. If BBAASSHHPPIIDD is unset, it loses its spe- + Expands to the process ID of the current bbaasshh process. This + differs from $$$$ under certain circumstances, such as subshells + that do not require bbaasshh to be re-initialized. Assignments to + BBAASSHHPPIIDD have no effect. If BBAASSHHPPIIDD is unset, it loses its spe- cial properties, even if it is subsequently reset. BBAASSHH__AALLIIAASSEESS - An associative array variable whose members correspond to the - internal list of aliases as maintained by the aalliiaass builtin. - Elements added to this array appear in the alias list; however, - unsetting array elements currently does not cause aliases to be + An associative array variable whose members correspond to the + internal list of aliases as maintained by the aalliiaass builtin. + Elements added to this array appear in the alias list; however, + unsetting array elements currently does not cause aliases to be removed from the alias list. If BBAASSHH__AALLIIAASSEESS is unset, it loses its special properties, even if it is subsequently reset. BBAASSHH__AARRGGCC - An array variable whose values are the number of parameters in + An array variable whose values are the number of parameters in each frame of the current bbaasshh execution call stack. The number - of parameters to the current subroutine (shell function or - script executed with .. or ssoouurrccee) is at the top of the stack. - When a subroutine is executed, the number of parameters passed + of parameters to the current subroutine (shell function or + script executed with .. or ssoouurrccee) is at the top of the stack. + When a subroutine is executed, the number of parameters passed is pushed onto BBAASSHH__AARRGGCC. The shell sets BBAASSHH__AARRGGCC only when in - extended debugging mode (see the description of the eexxttddeebbuugg - option to the sshhoopptt builtin below). Setting eexxttddeebbuugg after the + extended debugging mode (see the description of the eexxttddeebbuugg op- + tion to the sshhoopptt builtin below). Setting eexxttddeebbuugg after the shell has started to execute a script, or referencing this vari- - able when eexxttddeebbuugg is not set, may result in inconsistent val- + able when eexxttddeebbuugg is not set, may result in inconsistent val- ues. BBAASSHH__AARRGGVV - An array variable containing all of the parameters in the cur- + An array variable containing all of the parameters in the cur- rent bbaasshh execution call stack. The final parameter of the last - subroutine call is at the top of the stack; the first parameter + subroutine call is at the top of the stack; the first parameter of the initial call is at the bottom. When a subroutine is exe- - cuted, the parameters supplied are pushed onto BBAASSHH__AARRGGVV. The - shell sets BBAASSHH__AARRGGVV only when in extended debugging mode (see - the description of the eexxttddeebbuugg option to the sshhoopptt builtin - below). Setting eexxttddeebbuugg after the shell has started to execute - a script, or referencing this variable when eexxttddeebbuugg is not set, + cuted, the parameters supplied are pushed onto BBAASSHH__AARRGGVV. The + shell sets BBAASSHH__AARRGGVV only when in extended debugging mode (see + the description of the eexxttddeebbuugg option to the sshhoopptt builtin be- + low). Setting eexxttddeebbuugg after the shell has started to execute a + script, or referencing this variable when eexxttddeebbuugg is not set, may result in inconsistent values. BBAASSHH__AARRGGVV00 - When referenced, this variable expands to the name of the shell + When referenced, this variable expands to the name of the shell or shell script (identical to $$00; see the description of special - parameter 0 above). Assignment to BBAASSHH__AARRGGVV00 causes the value - assigned to also be assigned to $$00. If BBAASSHH__AARRGGVV00 is unset, it + parameter 0 above). Assignment to BBAASSHH__AARRGGVV00 causes the value + assigned to also be assigned to $$00. If BBAASSHH__AARRGGVV00 is unset, it loses its special properties, even if it is subsequently reset. BBAASSHH__CCMMDDSS - An associative array variable whose members correspond to the - internal hash table of commands as maintained by the hhaasshh + An associative array variable whose members correspond to the + internal hash table of commands as maintained by the hhaasshh builtin. Elements added to this array appear in the hash table; - however, unsetting array elements currently does not cause com- - mand names to be removed from the hash table. If BBAASSHH__CCMMDDSS is - unset, it loses its special properties, even if it is subse- + however, unsetting array elements currently does not cause com- + mand names to be removed from the hash table. If BBAASSHH__CCMMDDSS is + unset, it loses its special properties, even if it is subse- quently reset. BBAASSHH__CCOOMMMMAANNDD - The command currently being executed or about to be executed, + The command currently being executed or about to be executed, unless the shell is executing a command as the result of a trap, - in which case it is the command executing at the time of the - trap. + in which case it is the command executing at the time of the + trap. If BBAASSHH__CCOOMMMMAANNDD is unset, it loses its special proper- + ties, even if it is subsequently reset. BBAASSHH__EEXXEECCUUTTIIOONN__SSTTRRIINNGG The command argument to the --cc invocation option. BBAASSHH__LLIINNEENNOO @@ -862,20 +874,20 @@ PPAARRAAMMEETTEERRSS BBAASSHH__RREEMMAATTCCHH An array variable whose members are assigned by the ==~~ binary operator to the [[[[ conditional command. The element with index - 0 is the portion of the string matching the entire regular - expression. The element with index _n is the portion of the - string matching the _nth parenthesized subexpression. This vari- - able is read-only. + 0 is the portion of the string matching the entire regular ex- + pression. The element with index _n is the portion of the string + matching the _nth parenthesized subexpression. BBAASSHH__SSOOUURRCCEE - An array variable whose members are the source filenames where - the corresponding shell function names in the FFUUNNCCNNAAMMEE array - variable are defined. The shell function $${{FFUUNNCCNNAAMMEE[[_$_i]]}} is - defined in the file $${{BBAASSHH__SSOOUURRCCEE[[_$_i]]}} and called from + An array variable whose members are the source filenames where + the corresponding shell function names in the FFUUNNCCNNAAMMEE array + variable are defined. The shell function $${{FFUUNNCCNNAAMMEE[[_$_i]]}} is de- + fined in the file $${{BBAASSHH__SSOOUURRCCEE[[_$_i]]}} and called from $${{BBAASSHH__SSOOUURRCCEE[[_$_i_+_1]]}}. BBAASSHH__SSUUBBSSHHEELLLL - Incremented by one within each subshell or subshell environment - when the shell begins executing in that environment. The ini- - tial value is 0. + Incremented by one within each subshell or subshell environment + when the shell begins executing in that environment. The ini- + tial value is 0. If BBAASSHH__SSUUBBSSHHEELLLL is unset, it loses its spe- + cial properties, even if it is subsequently reset. BBAASSHH__VVEERRSSIINNFFOO A readonly array variable whose members hold version information for this instance of bbaasshh. The values assigned to the array @@ -925,8 +937,8 @@ PPAARRAAMMEETTEERRSS CCOOMMPP__WWOORRDDSS An array variable (see AArrrraayyss below) consisting of the individ- ual words in the current command line. The line is split into - words as rreeaaddlliinnee would split it, using CCOOMMPP__WWOORRDDBBRREEAAKKSS as - described above. This variable is available only in shell func- + words as rreeaaddlliinnee would split it, using CCOOMMPP__WWOORRDDBBRREEAAKKSS as de- + scribed above. This variable is available only in shell func- tions invoked by the programmable completion facilities (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). CCOOPPRROOCC An array variable (see AArrrraayyss below) created to hold the file @@ -939,9 +951,9 @@ PPAARRAAMMEETTEERRSS to members of this array variable may be used to modify directo- ries already in the stack, but the ppuusshhdd and ppooppdd builtins must be used to add and remove directories. Assignment to this vari- - able will not change the current directory. If DDIIRRSSTTAACCKK is - unset, it loses its special properties, even if it is subse- - quently reset. + able will not change the current directory. If DDIIRRSSTTAACCKK is un- + set, it loses its special properties, even if it is subsequently + reset. EEPPOOCCHHRREEAALLTTIIMMEE Each time this parameter is referenced, it expands to the number of seconds since the Unix Epoch (see _t_i_m_e(3)) as a floating @@ -962,13 +974,13 @@ PPAARRAAMMEETTEERRSS tom-most element (the one with the highest index) is "main". This variable exists only when a shell function is executing. Assignments to FFUUNNCCNNAAMMEE have no effect. If FFUUNNCCNNAAMMEE is unset, - it loses its special properties, even if it is subsequently - reset. + it loses its special properties, even if it is subsequently re- + set. This variable can be used with BBAASSHH__LLIINNEENNOO and BBAASSHH__SSOOUURRCCEE. Each element of FFUUNNCCNNAAMMEE has corresponding elements in - BBAASSHH__LLIINNEENNOO and BBAASSHH__SSOOUURRCCEE to describe the call stack. For - instance, $${{FFUUNNCCNNAAMMEE[[_$_i]]}} was called from the file + BBAASSHH__LLIINNEENNOO and BBAASSHH__SSOOUURRCCEE to describe the call stack. For in- + stance, $${{FFUUNNCCNNAAMMEE[[_$_i]]}} was called from the file $${{BBAASSHH__SSOOUURRCCEE[[_$_i_+_1]]}} at line number $${{BBAASSHH__LLIINNEENNOO[[_$_i]]}}. The ccaalllleerr builtin displays the current call stack using this infor- mation. @@ -978,50 +990,56 @@ PPAARRAAMMEETTEERRSS is subsequently reset. HHIISSTTCCMMDD The history number, or index in the history list, of the current - command. If HHIISSTTCCMMDD is unset, it loses its special properties, - even if it is subsequently reset. + command. Assignments to HHIISSTTCCMMDD are ignored. If HHIISSTTCCMMDD is un- + set, it loses its special properties, even if it is subsequently + reset. HHOOSSTTNNAAMMEE Automatically set to the name of the current host. HHOOSSTTTTYYPPEE - Automatically set to a string that uniquely describes the type - of machine on which bbaasshh is executing. The default is system- + Automatically set to a string that uniquely describes the type + of machine on which bbaasshh is executing. The default is system- dependent. - LLIINNEENNOO Each time this parameter is referenced, the shell substitutes a - decimal number representing the current sequential line number - (starting with 1) within a script or function. When not in a - script or function, the value substituted is not guaranteed to + LLIINNEENNOO Each time this parameter is referenced, the shell substitutes a + decimal number representing the current sequential line number + (starting with 1) within a script or function. When not in a + script or function, the value substituted is not guaranteed to be meaningful. If LLIINNEENNOO is unset, it loses its special proper- ties, even if it is subsequently reset. MMAACCHHTTYYPPEE - Automatically set to a string that fully describes the system - type on which bbaasshh is executing, in the standard GNU _c_p_u_-_c_o_m_- + Automatically set to a string that fully describes the system + type on which bbaasshh is executing, in the standard GNU _c_p_u_-_c_o_m_- _p_a_n_y_-_s_y_s_t_e_m format. The default is system-dependent. MMAAPPFFIILLEE - An array variable (see AArrrraayyss below) created to hold the text + An array variable (see AArrrraayyss below) created to hold the text read by the mmaappffiillee builtin when no variable name is supplied. OOLLDDPPWWDD The previous working directory as set by the ccdd command. - OOPPTTAARRGG The value of the last option argument processed by the ggeettooppttss + OOPPTTAARRGG The value of the last option argument processed by the ggeettooppttss builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - OOPPTTIINNDD The index of the next argument to be processed by the ggeettooppttss + OOPPTTIINNDD The index of the next argument to be processed by the ggeettooppttss builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - OOSSTTYYPPEE Automatically set to a string that describes the operating sys- - tem on which bbaasshh is executing. The default is system-depen- + OOSSTTYYPPEE Automatically set to a string that describes the operating sys- + tem on which bbaasshh is executing. The default is system-depen- dent. PPIIPPEESSTTAATTUUSS - An array variable (see AArrrraayyss below) containing a list of exit - status values from the processes in the most-recently-executed + An array variable (see AArrrraayyss below) containing a list of exit + status values from the processes in the most-recently-executed foreground pipeline (which may contain only a single command). - PPPPIIDD The process ID of the shell's parent. This variable is read- + PPPPIIDD The process ID of the shell's parent. This variable is read- only. PPWWDD The current working directory as set by the ccdd command. - RRAANNDDOOMM Each time this parameter is referenced, a random integer between - 0 and 32767 is generated. The sequence of random numbers may be - initialized by assigning a value to RRAANNDDOOMM. If RRAANNDDOOMM is unset, - it loses its special properties, even if it is subsequently - reset. + RRAANNDDOOMM Each time this parameter is referenced, it expands to a random + integer between 0 and 32767. Assigning a value to RRAANNDDOOMM ini- + tializes (seeds) the sequence of random numbers. If RRAANNDDOOMM is + unset, it loses its special properties, even if it is subse- + quently reset. RREEAADDLLIINNEE__LLIINNEE The contents of the rreeaaddlliinnee line buffer, for use with "bind -x" (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). + RREEAADDLLIINNEE__MMAARRKK + The position of the mark (saved insertion point) in the rreeaaddlliinnee + line buffer, for use with "bind -x" (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS + below). The characters between the insertion point and the mark + are often called the _r_e_g_i_o_n. RREEAADDLLIINNEE__PPOOIINNTT The position of the insertion point in the rreeaaddlliinnee line buffer, for use with "bind -x" (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). @@ -1032,8 +1050,10 @@ PPAARRAAMMEETTEERRSS since shell invocation is returned. If a value is assigned to SSEECCOONNDDSS, the value returned upon subsequent references is the number of seconds since the assignment plus the value assigned. - If SSEECCOONNDDSS is unset, it loses its special properties, even if it - is subsequently reset. + The number of seconds at shell invocation and the current time + is always determined by querying the system clock. If SSEECCOONNDDSS + is unset, it loses its special properties, even if it is subse- + quently reset. SSHHEELLLLOOPPTTSS A colon-separated list of enabled shell options. Each word in the list is a valid argument for the --oo option to the sseett @@ -1043,27 +1063,35 @@ PPAARRAAMMEETTEERRSS shell option in the list will be enabled before reading any startup files. This variable is read-only. SSHHLLVVLL Incremented by one each time an instance of bbaasshh is started. + SSRRAANNDDOOMM + This variable expands to a 32-bit pseudo-random number each time + it is referenced. The random number generator is not linear on + systems that support /dev/urandom or _a_r_c_4_r_a_n_d_o_m, so each re- + turned number has no relationship to the numbers preceding it. + The random number generator cannot be seeded, so assignments to + this variable have no effect. If SSRRAANNDDOOMM is unset, it loses its + special properties, even if it is subsequently reset. UUIIDD Expands to the user ID of the current user, initialized at shell startup. This variable is readonly. - The following variables are used by the shell. In some cases, bbaasshh - assigns a default value to a variable; these cases are noted below. + The following variables are used by the shell. In some cases, bbaasshh as- + signs a default value to a variable; these cases are noted below. BBAASSHH__CCOOMMPPAATT The value is used to set the shell's compatibility level. See - the description of the sshhoopptt builtin below under SSHHEELLLL BBUUIILLTTIINN - CCOOMMMMAANNDDSS for a description of the various compatibility levels - and their effects. The value may be a decimal number (e.g., - 4.2) or an integer (e.g., 42) corresponding to the desired com- - patibility level. If BBAASSHH__CCOOMMPPAATT is unset or set to the empty - string, the compatibility level is set to the default for the - current version. If BBAASSHH__CCOOMMPPAATT is set to a value that is not - one of the valid compatibility levels, the shell prints an error - message and sets the compatibility level to the default for the - current version. The valid compatibility levels correspond to - the compatibility options accepted by the sshhoopptt builtin - described below (for example, ccoommppaatt4422 means that 4.2 and 42 are - valid values). The current version is also a valid value. + SSHHEELLLL CCOOMMPPAATTIIBBIILLIITTYY MMOODDEE below for a description of the various + compatibility levels and their effects. The value may be a dec- + imal number (e.g., 4.2) or an integer (e.g., 42) corresponding + to the desired compatibility level. If BBAASSHH__CCOOMMPPAATT is unset or + set to the empty string, the compatibility level is set to the + default for the current version. If BBAASSHH__CCOOMMPPAATT is set to a + value that is not one of the valid compatibility levels, the + shell prints an error message and sets the compatibility level + to the default for the current version. The valid values corre- + spond to the compatibility levels described below under BBSSHHEELLLL-- + COMPATIBILITYMMOODDEE. For example, 4.2 and 42 are valid values + that correspond to the ccoommppaatt4422 sshhoopptt option and set the compat- + ibility level to 42. The current version is also a valid value. BBAASSHH__EENNVV If this parameter is set when bbaasshh is executing a shell script, its value is interpreted as a filename containing commands to @@ -1073,16 +1101,16 @@ PPAARRAAMMEETTEERRSS PPAATTHH is not used to search for the resultant filename. BBAASSHH__XXTTRRAACCEEFFDD If set to an integer corresponding to a valid file descriptor, - bbaasshh will write the trace output generated when _s_e_t _-_x is - enabled to that file descriptor. The file descriptor is closed + bbaasshh will write the trace output generated when _s_e_t _-_x is en- + abled to that file descriptor. The file descriptor is closed when BBAASSHH__XXTTRRAACCEEFFDD is unset or assigned a new value. Unsetting BBAASSHH__XXTTRRAACCEEFFDD or assigning it the empty string causes the trace output to be sent to the standard error. Note that setting BBAASSHH__XXTTRRAACCEEFFDD to 2 (the standard error file descriptor) and then unsetting it will result in the standard error being closed. CCDDPPAATTHH The search path for the ccdd command. This is a colon-separated - list of directories in which the shell looks for destination - directories specified by the ccdd command. A sample value is + list of directories in which the shell looks for destination di- + rectories specified by the ccdd command. A sample value is ".:~:/usr". CCHHIILLDD__MMAAXX Set the number of exited child status values for the shell to @@ -1098,13 +1126,13 @@ PPAARRAAMMEETTEERRSS CCOOMMPPRREEPPLLYY An array variable from which bbaasshh reads the possible completions generated by a shell function invoked by the programmable com- - pletion facility (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). Each - array element contains one possible completion. + pletion facility (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). Each ar- + ray element contains one possible completion. EEMMAACCSS If bbaasshh finds this variable in the environment when the shell starts with value "t", it assumes that the shell is running in an Emacs shell buffer and disables line editing. - EENNVV Similar to BBAASSHH__EENNVV; used when the shell is invoked in _p_o_s_i_x - _m_o_d_e. + EENNVV Expanded and executed similarly to BBAASSHH__EENNVV (see IINNVVOOCCAATTIIOONN + above) when an interactive shell is invoked in _p_o_s_i_x _m_o_d_e. EEXXEECCIIGGNNOORREE A colon-separated list of shell patterns (see PPaatttteerrnn MMaattcchhiinngg) defining the list of filenames to be ignored by command search @@ -1133,8 +1161,8 @@ PPAARRAAMMEETTEERRSS patterns in GGLLOOBBIIGGNNOORREE, it is removed from the list of matches. HHIISSTTCCOONNTTRROOLL A colon-separated list of values controlling how commands are - saved on the history list. If the list of values includes - _i_g_n_o_r_e_s_p_a_c_e, lines which begin with a ssppaaccee character are not + saved on the history list. If the list of values includes _i_g_- + _n_o_r_e_s_p_a_c_e, lines which begin with a ssppaaccee character are not saved in the history list. A value of _i_g_n_o_r_e_d_u_p_s causes lines matching the previous history entry to not be saved. A value of _i_g_n_o_r_e_b_o_t_h is shorthand for _i_g_n_o_r_e_s_p_a_c_e and _i_g_n_o_r_e_d_u_p_s. A value @@ -1162,17 +1190,17 @@ PPAARRAAMMEETTEERRSS HHIISSTTSSIIZZEE after reading any startup files. HHIISSTTIIGGNNOORREE A colon-separated list of patterns used to decide which command - lines should be saved on the history list. Each pattern is - anchored at the beginning of the line and must match the com- - plete line (no implicit `**' is appended). Each pattern is - tested against the line after the checks specified by HHIISSTTCCOONN-- - TTRROOLL are applied. In addition to the normal shell pattern - matching characters, `&&' matches the previous history line. `&&' - may be escaped using a backslash; the backslash is removed - before attempting a match. The second and subsequent lines of a - multi-line compound command are not tested, and are added to the - history regardless of the value of HHIISSTTIIGGNNOORREE. The pattern - matching honors the setting of the eexxttgglloobb shell option. + lines should be saved on the history list. Each pattern is an- + chored at the beginning of the line and must match the complete + line (no implicit `**' is appended). Each pattern is tested + against the line after the checks specified by HHIISSTTCCOONNTTRROOLL are + applied. In addition to the normal shell pattern matching char- + acters, `&&' matches the previous history line. `&&' may be es- + caped using a backslash; the backslash is removed before at- + tempting a match. The second and subsequent lines of a multi- + line compound command are not tested, and are added to the his- + tory regardless of the value of HHIISSTTIIGGNNOORREE. The pattern match- + ing honors the setting of the eexxttgglloobb shell option. HHIISSTTSSIIZZEE The number of commands to remember in the command history (see HHIISSTTOORRYY below). If the value is 0, commands are not saved in @@ -1195,14 +1223,14 @@ PPAARRAAMMEETTEERRSS Contains the name of a file in the same format as _/_e_t_c_/_h_o_s_t_s that should be read when the shell needs to complete a hostname. The list of possible hostname completions may be changed while - the shell is running; the next time hostname completion is - attempted after the value is changed, bbaasshh adds the contents of + the shell is running; the next time hostname completion is at- + tempted after the value is changed, bbaasshh adds the contents of the new file to the existing list. If HHOOSSTTFFIILLEE is set, but has no value, or does not name a readable file, bbaasshh attempts to read _/_e_t_c_/_h_o_s_t_s to obtain the list of possible hostname comple- tions. When HHOOSSTTFFIILLEE is unset, the hostname list is cleared. - IIFFSS The _I_n_t_e_r_n_a_l _F_i_e_l_d _S_e_p_a_r_a_t_o_r that is used for word splitting - after expansion and to split lines into words with the rreeaadd + IIFFSS The _I_n_t_e_r_n_a_l _F_i_e_l_d _S_e_p_a_r_a_t_o_r that is used for word splitting af- + ter expansion and to split lines into words with the rreeaadd builtin command. The default value is ``<space><tab><new- line>''. IIGGNNOORREEEEOOFF @@ -1214,8 +1242,8 @@ PPAARRAAMMEETTEERRSS default value is 10. If it does not exist, EEOOFF signifies the end of input to the shell. IINNPPUUTTRRCC - The filename for the rreeaaddlliinnee startup file, overriding the - default of _~_/_._i_n_p_u_t_r_c (see RREEAADDLLIINNEE below). + The filename for the rreeaaddlliinnee startup file, overriding the de- + fault of _~_/_._i_n_p_u_t_r_c (see RREEAADDLLIINNEE below). IINNSSIIDDEE__EEMMAACCSS If this variable appears in the environment when the shell starts, bbaasshh assumes that it is running inside an Emacs shell @@ -1228,8 +1256,8 @@ PPAARRAAMMEETTEERRSS LLCC__CCOOLLLLAATTEE This variable determines the collation order used when sorting the results of pathname expansion, and determines the behavior - of range expressions, equivalence classes, and collating - sequences within pathname expansion and pattern matching. + of range expressions, equivalence classes, and collating se- + quences within pathname expansion and pattern matching. LLCC__CCTTYYPPEE This variable determines the interpretation of characters and the behavior of character classes within pathname expansion and @@ -1248,78 +1276,80 @@ PPAARRAAMMEETTEERRSS cchheecckkwwiinnssiizzee option is enabled or in an interactive shell upon receipt of a SSIIGGWWIINNCCHH. MMAAIILL If this parameter is set to a file or directory name and the - MMAAIILLPPAATTHH variable is not set, bbaasshh informs the user of the - arrival of mail in the specified file or Maildir-format direc- - tory. + MMAAIILLPPAATTHH variable is not set, bbaasshh informs the user of the ar- + rival of mail in the specified file or Maildir-format directory. MMAAIILLCCHHEECCKK - Specifies how often (in seconds) bbaasshh checks for mail. The - default is 60 seconds. When it is time to check for mail, the - shell does so before displaying the primary prompt. If this - variable is unset, or set to a value that is not a number + Specifies how often (in seconds) bbaasshh checks for mail. The de- + fault is 60 seconds. When it is time to check for mail, the + shell does so before displaying the primary prompt. If this + variable is unset, or set to a value that is not a number greater than or equal to zero, the shell disables mail checking. MMAAIILLPPAATTHH A colon-separated list of filenames to be checked for mail. The message to be printed when mail arrives in a particular file may - be specified by separating the filename from the message with a - `?'. When used in the text of the message, $$__ expands to the + be specified by separating the filename from the message with a + `?'. When used in the text of the message, $$__ expands to the name of the current mailfile. Example: MMAAIILLPPAATTHH='/var/mail/bfox?"You have mail":~/shell-mail?"$_ has mail!"' - BBaasshh can be configured to supply a default value for this vari- - able (there is no value by default), but the location of the + BBaasshh can be configured to supply a default value for this vari- + able (there is no value by default), but the location of the user mail files that it uses is system dependent (e.g., /var/mail/$$UUSSEERR). OOPPTTEERRRR If set to the value 1, bbaasshh displays error messages generated by - the ggeettooppttss builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - OOPPTTEERRRR is initialized to 1 each time the shell is invoked or a + the ggeettooppttss builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). + OOPPTTEERRRR is initialized to 1 each time the shell is invoked or a shell script is executed. - PPAATTHH The search path for commands. It is a colon-separated list of - directories in which the shell looks for commands (see CCOOMMMMAANNDD - EEXXEECCUUTTIIOONN below). A zero-length (null) directory name in the + PPAATTHH The search path for commands. It is a colon-separated list of + directories in which the shell looks for commands (see CCOOMMMMAANNDD + EEXXEECCUUTTIIOONN below). A zero-length (null) directory name in the value of PPAATTHH indicates the current directory. A null directory - name may appear as two adjacent colons, or as an initial or - trailing colon. The default path is system-dependent, and is + name may appear as two adjacent colons, or as an initial or + trailing colon. The default path is system-dependent, and is set by the administrator who installs bbaasshh. A common value is - ``/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin''. + ``/usr/local/bin:/usr/lo- + cal/sbin:/usr/bin:/usr/sbin:/bin:/sbin''. PPOOSSIIXXLLYY__CCOORRRREECCTT - If this variable is in the environment when bbaasshh starts, the - shell enters _p_o_s_i_x _m_o_d_e before reading the startup files, as if - the ----ppoossiixx invocation option had been supplied. If it is set - while the shell is running, bbaasshh enables _p_o_s_i_x _m_o_d_e, as if the - command _s_e_t _-_o _p_o_s_i_x had been executed. When the shell enters + If this variable is in the environment when bbaasshh starts, the + shell enters _p_o_s_i_x _m_o_d_e before reading the startup files, as if + the ----ppoossiixx invocation option had been supplied. If it is set + while the shell is running, bbaasshh enables _p_o_s_i_x _m_o_d_e, as if the + command _s_e_t _-_o _p_o_s_i_x had been executed. When the shell enters _p_o_s_i_x _m_o_d_e, it sets this variable if it was not already set. PPRROOMMPPTT__CCOOMMMMAANNDD - If set, the value is executed as a command prior to issuing each - primary prompt. + If this variable is set, and is an array, the value of each set + element is executed as a command prior to issuing each primary + prompt. If this is set but not an array variable, its value is + used as a command to execute instead. PPRROOMMPPTT__DDIIRRTTRRIIMM - If set to a number greater than zero, the value is used as the + If set to a number greater than zero, the value is used as the number of trailing directory components to retain when expanding - the \\ww and \\WW prompt string escapes (see PPRROOMMPPTTIINNGG below). + the \\ww and \\WW prompt string escapes (see PPRROOMMPPTTIINNGG below). Characters removed are replaced with an ellipsis. - PPSS00 The value of this parameter is expanded (see PPRROOMMPPTTIINNGG below) - and displayed by interactive shells after reading a command and + PPSS00 The value of this parameter is expanded (see PPRROOMMPPTTIINNGG below) + and displayed by interactive shells after reading a command and before the command is executed. - PPSS11 The value of this parameter is expanded (see PPRROOMMPPTTIINNGG below) - and used as the primary prompt string. The default value is + PPSS11 The value of this parameter is expanded (see PPRROOMMPPTTIINNGG below) + and used as the primary prompt string. The default value is ``\\ss--\\vv\\$$ ''. - PPSS22 The value of this parameter is expanded as with PPSS11 and used as + PPSS22 The value of this parameter is expanded as with PPSS11 and used as the secondary prompt string. The default is ``>> ''. PPSS33 The value of this parameter is used as the prompt for the sseelleecctt command (see SSHHEELLLL GGRRAAMMMMAARR above). - PPSS44 The value of this parameter is expanded as with PPSS11 and the - value is printed before each command bbaasshh displays during an - execution trace. The first character of the expanded value of - PPSS44 is replicated multiple times, as necessary, to indicate mul- - tiple levels of indirection. The default is ``++ ''. - SSHHEELLLL The full pathname to the shell is kept in this environment vari- - able. If it is not set when the shell starts, bbaasshh assigns to - it the full pathname of the current user's login shell. + PPSS44 The value of this parameter is expanded as with PPSS11 and the + value is printed before each command bbaasshh displays during an ex- + ecution trace. The first character of the expanded value of PPSS44 + is replicated multiple times, as necessary, to indicate multiple + levels of indirection. The default is ``++ ''. + SSHHEELLLL This variable expands to the full pathname to the shell. If it + is not set when the shell starts, bbaasshh assigns to it the full + pathname of the current user's login shell. TTIIMMEEFFOORRMMAATT - The value of this parameter is used as a format string specify- - ing how the timing information for pipelines prefixed with the - ttiimmee reserved word should be displayed. The %% character intro- - duces an escape sequence that is expanded to a time value or - other information. The escape sequences and their meanings are + The value of this parameter is used as a format string specify- + ing how the timing information for pipelines prefixed with the + ttiimmee reserved word should be displayed. The %% character intro- + duces an escape sequence that is expanded to a time value or + other information. The escape sequences and their meanings are as follows; the braces denote optional portions. %%%% A literal %%. %%[[_p]][[ll]]RR The elapsed time in seconds. @@ -1327,77 +1357,77 @@ PPAARRAAMMEETTEERRSS %%[[_p]][[ll]]SS The number of CPU seconds spent in system mode. %%PP The CPU percentage, computed as (%U + %S) / %R. - The optional _p is a digit specifying the _p_r_e_c_i_s_i_o_n, the number + The optional _p is a digit specifying the _p_r_e_c_i_s_i_o_n, the number of fractional digits after a decimal point. A value of 0 causes no decimal point or fraction to be output. At most three places - after the decimal point may be specified; values of _p greater - than 3 are changed to 3. If _p is not specified, the value 3 is + after the decimal point may be specified; values of _p greater + than 3 are changed to 3. If _p is not specified, the value 3 is used. - The optional ll specifies a longer format, including minutes, of - the form _M_Mm_S_S._F_Fs. The value of _p determines whether or not + The optional ll specifies a longer format, including minutes, of + the form _M_Mm_S_S._F_Fs. The value of _p determines whether or not the fraction is included. - If this variable is not set, bbaasshh acts as if it had the value - $$''\\nnrreeaall\\tt%%33llRR\\nnuusseerr\\tt%%33llUU\\nnssyyss\\tt%%33llSS''. If the value is null, + If this variable is not set, bbaasshh acts as if it had the value + $$''\\nnrreeaall\\tt%%33llRR\\nnuusseerr\\tt%%33llUU\\nnssyyss\\tt%%33llSS''. If the value is null, no timing information is displayed. A trailing newline is added when the format string is displayed. - TTMMOOUUTT If set to a value greater than zero, TTMMOOUUTT is treated as the - default timeout for the rreeaadd builtin. The sseelleecctt command termi- + TTMMOOUUTT If set to a value greater than zero, TTMMOOUUTT is treated as the de- + fault timeout for the rreeaadd builtin. The sseelleecctt command termi- nates if input does not arrive after TTMMOOUUTT seconds when input is - coming from a terminal. In an interactive shell, the value is + coming from a terminal. In an interactive shell, the value is interpreted as the number of seconds to wait for a line of input after issuing the primary prompt. BBaasshh terminates after waiting - for that number of seconds if a complete line of input does not + for that number of seconds if a complete line of input does not arrive. - TTMMPPDDIIRR If set, bbaasshh uses its value as the name of a directory in which + TTMMPPDDIIRR If set, bbaasshh uses its value as the name of a directory in which bbaasshh creates temporary files for the shell's use. aauuttoo__rreessuummee This variable controls how the shell interacts with the user and - job control. If this variable is set, single word simple com- + job control. If this variable is set, single word simple com- mands without redirections are treated as candidates for resump- tion of an existing stopped job. There is no ambiguity allowed; - if there is more than one job beginning with the string typed, - the job most recently accessed is selected. The _n_a_m_e of a - stopped job, in this context, is the command line used to start - it. If set to the value _e_x_a_c_t, the string supplied must match - the name of a stopped job exactly; if set to _s_u_b_s_t_r_i_n_g, the - string supplied needs to match a substring of the name of a - stopped job. The _s_u_b_s_t_r_i_n_g value provides functionality analo- - gous to the %%?? job identifier (see JJOOBB CCOONNTTRROOLL below). If set - to any other value, the supplied string must be a prefix of a + if there is more than one job beginning with the string typed, + the job most recently accessed is selected. The _n_a_m_e of a + stopped job, in this context, is the command line used to start + it. If set to the value _e_x_a_c_t, the string supplied must match + the name of a stopped job exactly; if set to _s_u_b_s_t_r_i_n_g, the + string supplied needs to match a substring of the name of a + stopped job. The _s_u_b_s_t_r_i_n_g value provides functionality analo- + gous to the %%?? job identifier (see JJOOBB CCOONNTTRROOLL below). If set + to any other value, the supplied string must be a prefix of a stopped job's name; this provides functionality analogous to the %%_s_t_r_i_n_g job identifier. hhiissttcchhaarrss - The two or three characters which control history expansion and + The two or three characters which control history expansion and tokenization (see HHIISSTTOORRYY EEXXPPAANNSSIIOONN below). The first character - is the _h_i_s_t_o_r_y _e_x_p_a_n_s_i_o_n character, the character which signals - the start of a history expansion, normally `!!'. The second - character is the _q_u_i_c_k _s_u_b_s_t_i_t_u_t_i_o_n character, which is used as - shorthand for re-running the previous command entered, substi- - tuting one string for another in the command. The default is - `^^'. The optional third character is the character which indi- - cates that the remainder of the line is a comment when found as - the first character of a word, normally `##'. The history com- + is the _h_i_s_t_o_r_y _e_x_p_a_n_s_i_o_n character, the character which signals + the start of a history expansion, normally `!!'. The second + character is the _q_u_i_c_k _s_u_b_s_t_i_t_u_t_i_o_n character, which is used as + shorthand for re-running the previous command entered, substi- + tuting one string for another in the command. The default is + `^^'. The optional third character is the character which indi- + cates that the remainder of the line is a comment when found as + the first character of a word, normally `##'. The history com- ment character causes history substitution to be skipped for the - remaining words on the line. It does not necessarily cause the + remaining words on the line. It does not necessarily cause the shell parser to treat the rest of the line as a comment. AArrrraayyss - BBaasshh provides one-dimensional indexed and associative array variables. - Any variable may be used as an indexed array; the ddeeccllaarree builtin will - explicitly declare an array. There is no maximum limit on the size of - an array, nor any requirement that members be indexed or assigned con- - tiguously. Indexed arrays are referenced using integers (including + BBaasshh provides one-dimensional indexed and associative array variables. + Any variable may be used as an indexed array; the ddeeccllaarree builtin will + explicitly declare an array. There is no maximum limit on the size of + an array, nor any requirement that members be indexed or assigned con- + tiguously. Indexed arrays are referenced using integers (including arithmetic expressions) and are zero-based; associative arrays are ref- erenced using arbitrary strings. Unless otherwise noted, indexed array indices must be non-negative integers. - An indexed array is created automatically if any variable is assigned + An indexed array is created automatically if any variable is assigned to using the syntax _n_a_m_e[_s_u_b_s_c_r_i_p_t]=_v_a_l_u_e. The _s_u_b_s_c_r_i_p_t is treated as an arithmetic expression that must evaluate to a number. To explicitly - declare an indexed array, use ddeeccllaarree --aa _n_a_m_e (see SSHHEELLLL BBUUIILLTTIINN CCOOMM-- - MMAANNDDSS below). ddeeccllaarree --aa _n_a_m_e[[_s_u_b_s_c_r_i_p_t]] is also accepted; the _s_u_b_- + declare an indexed array, use ddeeccllaarree --aa _n_a_m_e (see SSHHEELLLL BBUUIILLTTIINN CCOOMM-- + MMAANNDDSS below). ddeeccllaarree --aa _n_a_m_e[[_s_u_b_s_c_r_i_p_t]] is also accepted; the _s_u_b_- _s_c_r_i_p_t is ignored. Associative arrays are created using ddeeccllaarree --AA _n_a_m_e. @@ -1405,19 +1435,28 @@ PPAARRAAMMEETTEERRSS Attributes may be specified for an array variable using the ddeeccllaarree and rreeaaddoonnllyy builtins. Each attribute applies to all members of an array. - Arrays are assigned to using compound assignments of the form - _n_a_m_e=((value_1 ... value_n)), where each _v_a_l_u_e is of the form [_s_u_b_- - _s_c_r_i_p_t]=_s_t_r_i_n_g. Indexed array assignments do not require anything but - _s_t_r_i_n_g. When assigning to indexed arrays, if the optional brackets and - subscript are supplied, that index is assigned to; otherwise the index - of the element assigned is the last index assigned to by the statement - plus one. Indexing starts at zero. - - When assigning to an associative array, the subscript is required. + Arrays are assigned to using compound assignments of the form + _n_a_m_e=((value_1 ... value_n)), where each _v_a_l_u_e may be of the form [_s_u_b_- + _s_c_r_i_p_t]=_s_t_r_i_n_g. Indexed array assignments do not require anything but + _s_t_r_i_n_g. Each _v_a_l_u_e in the list is expanded using all the shell expan- + sions described below under EEXXPPAANNSSIIOONN. When assigning to indexed ar- + rays, if the optional brackets and subscript are supplied, that index + is assigned to; otherwise the index of the element assigned is the last + index assigned to by the statement plus one. Indexing starts at zero. + + When assigning to an associative array, the words in a compound assign- + ment may be either assignment statements, for which the subscript is + required, or a list of words that is interpreted as a sequence of al- + ternating keys and values: _n_a_m_e=(( _k_e_y_1 _v_a_l_u_e_1 _k_e_y_2 _v_a_l_u_e_2 ...)). These + are treated identically to _n_a_m_e=(( [_k_e_y_1]=_v_a_l_u_e_1 [_k_e_y_2]=_v_a_l_u_e_2 ...)). + The first word in the list determines how the remaining words are in- + terpreted; all assignments in a list must be of the same type. When + using key/value pairs, the keys may not be missing or empty; a final + missing value is treated like the empty string. This syntax is also accepted by the ddeeccllaarree builtin. Individual array - elements may be assigned to using the _n_a_m_e[_s_u_b_s_c_r_i_p_t]=_v_a_l_u_e syntax - introduced above. When assigning to an indexed array, if _n_a_m_e is sub- + elements may be assigned to using the _n_a_m_e[_s_u_b_s_c_r_i_p_t]=_v_a_l_u_e syntax in- + troduced above. When assigning to an indexed array, if _n_a_m_e is sub- scripted by a negative number, that number is interpreted as relative to one greater than the maximum index of _n_a_m_e, so negative indices count back from the end of the array, and an index of -1 references the @@ -1431,18 +1470,18 @@ PPAARRAAMMEETTEERRSS value of each array member separated by the first character of the IIFFSS special variable, and ${_n_a_m_e[@]} expands each element of _n_a_m_e to a sep- arate word. When there are no array members, ${_n_a_m_e[@]} expands to - nothing. If the double-quoted expansion occurs within a word, the - expansion of the first parameter is joined with the beginning part of - the original word, and the expansion of the last parameter is joined - with the last part of the original word. This is analogous to the - expansion of the special parameters ** and @@ (see SSppeecciiaall PPaarraammeetteerrss - above). ${#_n_a_m_e[_s_u_b_s_c_r_i_p_t]} expands to the length of ${_n_a_m_e[_s_u_b_- - _s_c_r_i_p_t]}. If _s_u_b_s_c_r_i_p_t is ** or @@, the expansion is the number of ele- - ments in the array. If the _s_u_b_s_c_r_i_p_t used to reference an element of - an indexed array evaluates to a number less than zero, it is inter- - preted as relative to one greater than the maximum index of the array, - so negative indices count back from the end of the array, and an index - of -1 references the last element. + nothing. If the double-quoted expansion occurs within a word, the ex- + pansion of the first parameter is joined with the beginning part of the + original word, and the expansion of the last parameter is joined with + the last part of the original word. This is analogous to the expansion + of the special parameters ** and @@ (see SSppeecciiaall PPaarraammeetteerrss above). + ${#_n_a_m_e[_s_u_b_s_c_r_i_p_t]} expands to the length of ${_n_a_m_e[_s_u_b_s_c_r_i_p_t]}. If + _s_u_b_s_c_r_i_p_t is ** or @@, the expansion is the number of elements in the ar- + ray. If the _s_u_b_s_c_r_i_p_t used to reference an element of an indexed array + evaluates to a number less than zero, it is interpreted as relative to + one greater than the maximum index of the array, so negative indices + count back from the end of the array, and an index of -1 references the + last element. Referencing an array variable without a subscript is equivalent to ref- erencing the array with a subscript of 0. Any reference to a variable @@ -1457,22 +1496,22 @@ PPAARRAAMMEETTEERRSS array variable _n_a_m_e. The treatment when in double quotes is similar to the expansion of the special parameters _@ and _* within double quotes. - The uunnsseett builtin is used to destroy arrays. uunnsseett _n_a_m_e[_s_u_b_s_c_r_i_p_t] - destroys the array element at index _s_u_b_s_c_r_i_p_t, for both indexed and - associative arrays. Negative subscripts to indexed arrays are inter- - preted as described above. Unsetting the last element of an array - variable does not unset the variable. uunnsseett _n_a_m_e, where _n_a_m_e is an - array, or uunnsseett _n_a_m_e[_s_u_b_s_c_r_i_p_t], where _s_u_b_s_c_r_i_p_t is ** or @@, removes the - entire array. + The uunnsseett builtin is used to destroy arrays. uunnsseett _n_a_m_e[_s_u_b_s_c_r_i_p_t] de- + stroys the array element at index _s_u_b_s_c_r_i_p_t, for both indexed and asso- + ciative arrays. Negative subscripts to indexed arrays are interpreted + as described above. Unsetting the last element of an array variable + does not unset the variable. uunnsseett _n_a_m_e, where _n_a_m_e is an array, or + uunnsseett _n_a_m_e[_s_u_b_s_c_r_i_p_t], where _s_u_b_s_c_r_i_p_t is ** or @@, removes the entire + array. When using a variable name with a subscript as an argument to a com- - mand, such as with uunnsseett, without using the word expansion syntax - described above, the argument is subject to pathname expansion. If - pathname expansion is not desired, the argument should be quoted. + mand, such as with uunnsseett, without using the word expansion syntax de- + scribed above, the argument is subject to pathname expansion. If path- + name expansion is not desired, the argument should be quoted. The ddeeccllaarree, llooccaall, and rreeaaddoonnllyy builtins each accept a --aa option to - specify an indexed array and a --AA option to specify an associative - array. If both options are supplied, --AA takes precedence. The rreeaadd + specify an indexed array and a --AA option to specify an associative ar- + ray. If both options are supplied, --AA takes precedence. The rreeaadd builtin accepts a --aa option to assign a list of words read from the standard input to an array. The sseett and ddeeccllaarree builtins display array values in a way that allows them to be reused as assignments. @@ -1497,10 +1536,10 @@ EEXXPPAANNSSIIOONN original word are removed unless they have been quoted themselves (_q_u_o_t_e _r_e_m_o_v_a_l). - Only brace expansion, word splitting, and pathname expansion can - increase the number of words of the expansion; other expansions expand - a single word to a single word. The only exceptions to this are the - expansions of "$$@@" and "$${{_n_a_m_e[[@@]]}}", and, in most cases, $$** and + Only brace expansion, word splitting, and pathname expansion can in- + crease the number of words of the expansion; other expansions expand a + single word to a single word. The only exceptions to this are the ex- + pansions of "$$@@" and "$${{_n_a_m_e[[@@]]}}", and, in most cases, $$** and $${{_n_a_m_e[[**]]}} as explained above (see PPAARRAAMMEETTEERRSS). BBrraaccee EExxppaannssiioonn @@ -1525,10 +1564,10 @@ EEXXPPAANNSSIIOONN or _y begins with a zero, the shell attempts to force all generated terms to contain the same number of digits, zero-padding where neces- sary. When characters are supplied, the expression expands to each - character lexicographically between _x and _y, inclusive, using the - default C locale. Note that both _x and _y must be of the same type. - When the increment is supplied, it is used as the difference between - each term. The default increment is 1 or -1 as appropriate. + character lexicographically between _x and _y, inclusive, using the de- + fault C locale. Note that both _x and _y must be of the same type. When + the increment is supplied, it is used as the difference between each + term. The default increment is 1 or -1 as appropriate. Brace expansion is performed before any other expansions, and any char- acters special to other expansions are preserved in the result. It is @@ -1536,9 +1575,9 @@ EEXXPPAANNSSIIOONN the context of the expansion or the text between the braces. A correctly-formed brace expansion must contain unquoted opening and - closing braces, and at least one unquoted comma or a valid sequence - expression. Any incorrectly formed brace expansion is left unchanged. - A {{ or ,, may be quoted with a backslash to prevent its being considered + closing braces, and at least one unquoted comma or a valid sequence ex- + pression. Any incorrectly formed brace expansion is left unchanged. A + {{ or ,, may be quoted with a backslash to prevent its being considered part of a brace expression. To avoid conflicts with parameter expan- sion, the string $${{ is not considered eligible for brace expansion, and inhibits brace expansion until the closing }}. @@ -1572,8 +1611,8 @@ EEXXPPAANNSSIIOONN wise, the tilde-prefix is replaced with the home directory associated with the specified login name. - If the tilde-prefix is a `~+', the value of the shell variable PPWWDD - replaces the tilde-prefix. If the tilde-prefix is a `~-', the value of + If the tilde-prefix is a `~+', the value of the shell variable PPWWDD re- + places the tilde-prefix. If the tilde-prefix is a `~-', the value of the shell variable OOLLDDPPWWDD, if it is set, is substituted. If the char- acters following the tilde in the tilde-prefix consist of a number _N, optionally prefixed by a `+' or a `-', the tilde-prefix is replaced @@ -1587,9 +1626,9 @@ EEXXPPAANNSSIIOONN Each variable assignment is checked for unquoted tilde-prefixes immedi- ately following a :: or the first ==. In these cases, tilde expansion is - also performed. Consequently, one may use filenames with tildes in - assignments to PPAATTHH, MMAAIILLPPAATTHH, and CCDDPPAATTHH, and the shell assigns the - expanded value. + also performed. Consequently, one may use filenames with tildes in as- + signments to PPAATTHH, MMAAIILLPPAATTHH, and CCDDPPAATTHH, and the shell assigns the ex- + panded value. Bash also performs tilde expansion on words satisfying the conditions of variable assignments (as described above under PPAARRAAMMEETTEERRSS) when they @@ -1604,9 +1643,9 @@ EEXXPPAANNSSIIOONN could be interpreted as part of the name. When braces are used, the matching ending brace is the first `}}' not - escaped by a backslash or within a quoted string, and not within an - embedded arithmetic expansion, command substitution, or parameter - expansion. + escaped by a backslash or within a quoted string, and not within an em- + bedded arithmetic expansion, command substitution, or parameter expan- + sion. ${_p_a_r_a_m_e_t_e_r} The value of _p_a_r_a_m_e_t_e_r is substituted. The braces are required @@ -1618,12 +1657,12 @@ EEXXPPAANNSSIIOONN If the first character of _p_a_r_a_m_e_t_e_r is an exclamation point (!!), and _p_a_r_a_m_e_t_e_r is not a _n_a_m_e_r_e_f, it introduces a level of indirection. BBaasshh - uses the value formed by expanding the rest of _p_a_r_a_m_e_t_e_r as the new - _p_a_r_a_m_e_t_e_r; this is then expanded and that value is used in the rest of + uses the value formed by expanding the rest of _p_a_r_a_m_e_t_e_r as the new _p_a_- + _r_a_m_e_t_e_r; this is then expanded and that value is used in the rest of the expansion, rather than the expansion of the original _p_a_r_a_m_e_t_e_r. - This is known as _i_n_d_i_r_e_c_t _e_x_p_a_n_s_i_o_n. The value is subject to tilde - expansion, parameter expansion, command substitution, and arithmetic - expansion. If _p_a_r_a_m_e_t_e_r is a nameref, this expands to the name of the + This is known as _i_n_d_i_r_e_c_t _e_x_p_a_n_s_i_o_n. The value is subject to tilde ex- + pansion, parameter expansion, command substitution, and arithmetic ex- + pansion. If _p_a_r_a_m_e_t_e_r is a nameref, this expands to the name of the parameter referenced by _p_a_r_a_m_e_t_e_r instead of performing the complete indirect expansion. The exceptions to this are the expansions of ${!!_p_r_e_f_i_x**} and ${!!_n_a_m_e[_@]} described below. The exclamation point @@ -1633,20 +1672,20 @@ EEXXPPAANNSSIIOONN In each of the cases below, _w_o_r_d is subject to tilde expansion, parame- ter expansion, command substitution, and arithmetic expansion. - When not performing substring expansion, using the forms documented - below (e.g., ::--), bbaasshh tests for a parameter that is unset or null. - Omitting the colon results in a test only for a parameter that is - unset. + When not performing substring expansion, using the forms documented be- + low (e.g., ::--), bbaasshh tests for a parameter that is unset or null. + Omitting the colon results in a test only for a parameter that is un- + set. ${_p_a_r_a_m_e_t_e_r::--_w_o_r_d} UUssee DDeeffaauulltt VVaalluueess. If _p_a_r_a_m_e_t_e_r is unset or null, the expan- sion of _w_o_r_d is substituted. Otherwise, the value of _p_a_r_a_m_e_t_e_r is substituted. ${_p_a_r_a_m_e_t_e_r::==_w_o_r_d} - AAssssiiggnn DDeeffaauulltt VVaalluueess. If _p_a_r_a_m_e_t_e_r is unset or null, the - expansion of _w_o_r_d is assigned to _p_a_r_a_m_e_t_e_r. The value of _p_a_r_a_m_- - _e_t_e_r is then substituted. Positional parameters and special - parameters may not be assigned to in this way. + AAssssiiggnn DDeeffaauulltt VVaalluueess. If _p_a_r_a_m_e_t_e_r is unset or null, the ex- + pansion of _w_o_r_d is assigned to _p_a_r_a_m_e_t_e_r. The value of _p_a_r_a_m_e_- + _t_e_r is then substituted. Positional parameters and special pa- + rameters may not be assigned to in this way. ${_p_a_r_a_m_e_t_e_r::??_w_o_r_d} DDiissppllaayy EErrrroorr iiff NNuullll oorr UUnnsseett. If _p_a_r_a_m_e_t_e_r is null or unset, the expansion of _w_o_r_d (or a message to that effect if _w_o_r_d is @@ -1668,35 +1707,33 @@ EEXXPPAANNSSIIOONN arithmetic expressions (see AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN below). If _o_f_f_s_e_t evaluates to a number less than zero, the value is - used as an offset in characters from the end of the value of - _p_a_r_a_m_e_t_e_r. If _l_e_n_g_t_h evaluates to a number less than zero, it - is interpreted as an offset in characters from the end of the - value of _p_a_r_a_m_e_t_e_r rather than a number of characters, and the - expansion is the characters between _o_f_f_s_e_t and that result. - Note that a negative offset must be separated from the colon by - at least one space to avoid being confused with the ::-- expan- - sion. - - If _p_a_r_a_m_e_t_e_r is @@, the result is _l_e_n_g_t_h positional parameters + used as an offset in characters from the end of the value of _p_a_- + _r_a_m_e_t_e_r. If _l_e_n_g_t_h evaluates to a number less than zero, it is + interpreted as an offset in characters from the end of the value + of _p_a_r_a_m_e_t_e_r rather than a number of characters, and the expan- + sion is the characters between _o_f_f_s_e_t and that result. Note + that a negative offset must be separated from the colon by at + least one space to avoid being confused with the ::-- expansion. + + If _p_a_r_a_m_e_t_e_r is @@, the result is _l_e_n_g_t_h positional parameters beginning at _o_f_f_s_e_t. A negative _o_f_f_s_e_t is taken relative to one - greater than the greatest positional parameter, so an offset of - -1 evaluates to the last positional parameter. It is an expan- + greater than the greatest positional parameter, so an offset of + -1 evaluates to the last positional parameter. It is an expan- sion error if _l_e_n_g_t_h evaluates to a number less than zero. If _p_a_r_a_m_e_t_e_r is an indexed array name subscripted by @ or *, the - result is the _l_e_n_g_t_h members of the array beginning with - ${_p_a_r_a_m_e_t_e_r[_o_f_f_s_e_t]}. A negative _o_f_f_s_e_t is taken relative to - one greater than the maximum index of the specified array. It - is an expansion error if _l_e_n_g_t_h evaluates to a number less than - zero. + result is the _l_e_n_g_t_h members of the array beginning with ${_p_a_- + _r_a_m_e_t_e_r[_o_f_f_s_e_t]}. A negative _o_f_f_s_e_t is taken relative to one + greater than the maximum index of the specified array. It is an + expansion error if _l_e_n_g_t_h evaluates to a number less than zero. - Substring expansion applied to an associative array produces - undefined results. + Substring expansion applied to an associative array produces un- + defined results. Substring indexing is zero-based unless the positional parame- - ters are used, in which case the indexing starts at 1 by - default. If _o_f_f_s_e_t is 0, and the positional parameters are - used, $$00 is prefixed to the list. + ters are used, in which case the indexing starts at 1 by de- + fault. If _o_f_f_s_e_t is 0, and the positional parameters are used, + $$00 is prefixed to the list. ${!!_p_r_e_f_i_x**} ${!!_p_r_e_f_i_x@@} @@ -1715,109 +1752,121 @@ EEXXPPAANNSSIIOONN each key expands to a separate word. ${##_p_a_r_a_m_e_t_e_r} - PPaarraammeetteerr lleennggtthh. The length in characters of the value of - _p_a_r_a_m_e_t_e_r is substituted. If _p_a_r_a_m_e_t_e_r is ** or @@, the value - substituted is the number of positional parameters. If _p_a_r_a_m_e_- - _t_e_r is an array name subscripted by ** or @@, the value substi- - tuted is the number of elements in the array. If _p_a_r_a_m_e_t_e_r is - an indexed array name subscripted by a negative number, that - number is interpreted as relative to one greater than the maxi- - mum index of _p_a_r_a_m_e_t_e_r, so negative indices count back from the - end of the array, and an index of -1 references the last ele- - ment. + PPaarraammeetteerr lleennggtthh. The length in characters of the value of _p_a_- + _r_a_m_e_t_e_r is substituted. If _p_a_r_a_m_e_t_e_r is ** or @@, the value sub- + stituted is the number of positional parameters. If _p_a_r_a_m_e_t_e_r + is an array name subscripted by ** or @@, the value substituted is + the number of elements in the array. If _p_a_r_a_m_e_t_e_r is an indexed + array name subscripted by a negative number, that number is in- + terpreted as relative to one greater than the maximum index of + _p_a_r_a_m_e_t_e_r, so negative indices count back from the end of the + array, and an index of -1 references the last element. ${_p_a_r_a_m_e_t_e_r##_w_o_r_d} ${_p_a_r_a_m_e_t_e_r####_w_o_r_d} RReemmoovvee mmaattcchhiinngg pprreeffiixx ppaatttteerrnn. The _w_o_r_d is expanded to produce a pattern just as in pathname expansion, and matched against the expanded value of _p_a_r_a_m_e_t_e_r using the rules described under PPaatt-- - tteerrnn MMaattcchhiinngg below. If the pattern matches the beginning of - the value of _p_a_r_a_m_e_t_e_r, then the result of the expansion is the - expanded value of _p_a_r_a_m_e_t_e_r with the shortest matching pattern - (the ``##'' case) or the longest matching pattern (the ``####'' - case) deleted. If _p_a_r_a_m_e_t_e_r is @@ or **, the pattern removal - operation is applied to each positional parameter in turn, and - the expansion is the resultant list. If _p_a_r_a_m_e_t_e_r is an array - variable subscripted with @@ or **, the pattern removal operation - is applied to each member of the array in turn, and the expan- - sion is the resultant list. + tteerrnn MMaattcchhiinngg below. If the pattern matches the beginning of + the value of _p_a_r_a_m_e_t_e_r, then the result of the expansion is the + expanded value of _p_a_r_a_m_e_t_e_r with the shortest matching pattern + (the ``##'' case) or the longest matching pattern (the ``####'' + case) deleted. If _p_a_r_a_m_e_t_e_r is @@ or **, the pattern removal op- + eration is applied to each positional parameter in turn, and the + expansion is the resultant list. If _p_a_r_a_m_e_t_e_r is an array vari- + able subscripted with @@ or **, the pattern removal operation is + applied to each member of the array in turn, and the expansion + is the resultant list. ${_p_a_r_a_m_e_t_e_r%%_w_o_r_d} ${_p_a_r_a_m_e_t_e_r%%%%_w_o_r_d} RReemmoovvee mmaattcchhiinngg ssuuffffiixx ppaatttteerrnn. The _w_o_r_d is expanded to produce a pattern just as in pathname expansion, and matched against the expanded value of _p_a_r_a_m_e_t_e_r using the rules described under PPaatt-- - tteerrnn MMaattcchhiinngg below. If the pattern matches a trailing portion - of the expanded value of _p_a_r_a_m_e_t_e_r, then the result of the - expansion is the expanded value of _p_a_r_a_m_e_t_e_r with the shortest - matching pattern (the ``%%'' case) or the longest matching pat- - tern (the ``%%%%'' case) deleted. If _p_a_r_a_m_e_t_e_r is @@ or **, the - pattern removal operation is applied to each positional parame- + tteerrnn MMaattcchhiinngg below. If the pattern matches a trailing portion + of the expanded value of _p_a_r_a_m_e_t_e_r, then the result of the ex- + pansion is the expanded value of _p_a_r_a_m_e_t_e_r with the shortest + matching pattern (the ``%%'' case) or the longest matching pat- + tern (the ``%%%%'' case) deleted. If _p_a_r_a_m_e_t_e_r is @@ or **, the + pattern removal operation is applied to each positional parame- ter in turn, and the expansion is the resultant list. If _p_a_r_a_m_- - _e_t_e_r is an array variable subscripted with @@ or **, the pattern - removal operation is applied to each member of the array in + _e_t_e_r is an array variable subscripted with @@ or **, the pattern + removal operation is applied to each member of the array in turn, and the expansion is the resultant list. ${_p_a_r_a_m_e_t_e_r//_p_a_t_t_e_r_n//_s_t_r_i_n_g} PPaatttteerrnn ssuubbssttiittuuttiioonn. The _p_a_t_t_e_r_n is expanded to produce a pat- - tern just as in pathname expansion, _P_a_r_a_m_e_t_e_r is expanded and - the longest match of _p_a_t_t_e_r_n against its value is replaced with - _s_t_r_i_n_g. The match is performed using the rules described under - PPaatttteerrnn MMaattcchhiinngg below. If _p_a_t_t_e_r_n begins with //, all matches - of _p_a_t_t_e_r_n are replaced with _s_t_r_i_n_g. Normally only the first - match is replaced. If _p_a_t_t_e_r_n begins with ##, it must match at - the beginning of the expanded value of _p_a_r_a_m_e_t_e_r. If _p_a_t_t_e_r_n + tern just as in pathname expansion, _P_a_r_a_m_e_t_e_r is expanded and + the longest match of _p_a_t_t_e_r_n against its value is replaced with + _s_t_r_i_n_g. The match is performed using the rules described under + PPaatttteerrnn MMaattcchhiinngg below. If _p_a_t_t_e_r_n begins with //, all matches + of _p_a_t_t_e_r_n are replaced with _s_t_r_i_n_g. Normally only the first + match is replaced. If _p_a_t_t_e_r_n begins with ##, it must match at + the beginning of the expanded value of _p_a_r_a_m_e_t_e_r. If _p_a_t_t_e_r_n begins with %%, it must match at the end of the expanded value of - _p_a_r_a_m_e_t_e_r. If _s_t_r_i_n_g is null, matches of _p_a_t_t_e_r_n are deleted - and the // following _p_a_t_t_e_r_n may be omitted. If the nnooccaasseemmaattcchh - shell option is enabled, the match is performed without regard - to the case of alphabetic characters. If _p_a_r_a_m_e_t_e_r is @@ or **, + _p_a_r_a_m_e_t_e_r. If _s_t_r_i_n_g is null, matches of _p_a_t_t_e_r_n are deleted + and the // following _p_a_t_t_e_r_n may be omitted. If the nnooccaasseemmaattcchh + shell option is enabled, the match is performed without regard + to the case of alphabetic characters. If _p_a_r_a_m_e_t_e_r is @@ or **, the substitution operation is applied to each positional parame- ter in turn, and the expansion is the resultant list. If _p_a_r_a_m_- _e_t_e_r is an array variable subscripted with @@ or **, the substitu- - tion operation is applied to each member of the array in turn, + tion operation is applied to each member of the array in turn, and the expansion is the resultant list. ${_p_a_r_a_m_e_t_e_r^^_p_a_t_t_e_r_n} ${_p_a_r_a_m_e_t_e_r^^^^_p_a_t_t_e_r_n} ${_p_a_r_a_m_e_t_e_r,,_p_a_t_t_e_r_n} ${_p_a_r_a_m_e_t_e_r,,,,_p_a_t_t_e_r_n} - CCaassee mmooddiiffiiccaattiioonn. This expansion modifies the case of alpha- - betic characters in _p_a_r_a_m_e_t_e_r. The _p_a_t_t_e_r_n is expanded to pro- + CCaassee mmooddiiffiiccaattiioonn. This expansion modifies the case of alpha- + betic characters in _p_a_r_a_m_e_t_e_r. The _p_a_t_t_e_r_n is expanded to pro- duce a pattern just as in pathname expansion. Each character in - the expanded value of _p_a_r_a_m_e_t_e_r is tested against _p_a_t_t_e_r_n, and, - if it matches the pattern, its case is converted. The pattern - should not attempt to match more than one character. The ^^ - operator converts lowercase letters matching _p_a_t_t_e_r_n to upper- - case; the ,, operator converts matching uppercase letters to low- - ercase. The ^^^^ and ,,,, expansions convert each matched character - in the expanded value; the ^^ and ,, expansions match and convert - only the first character in the expanded value. If _p_a_t_t_e_r_n is - omitted, it is treated like a ??, which matches every character. - If _p_a_r_a_m_e_t_e_r is @@ or **, the case modification operation is - applied to each positional parameter in turn, and the expansion - is the resultant list. If _p_a_r_a_m_e_t_e_r is an array variable sub- - scripted with @@ or **, the case modification operation is applied - to each member of the array in turn, and the expansion is the - resultant list. + the expanded value of _p_a_r_a_m_e_t_e_r is tested against _p_a_t_t_e_r_n, and, + if it matches the pattern, its case is converted. The pattern + should not attempt to match more than one character. The ^^ op- + erator converts lowercase letters matching _p_a_t_t_e_r_n to uppercase; + the ,, operator converts matching uppercase letters to lowercase. + The ^^^^ and ,,,, expansions convert each matched character in the + expanded value; the ^^ and ,, expansions match and convert only + the first character in the expanded value. If _p_a_t_t_e_r_n is omit- + ted, it is treated like a ??, which matches every character. If + _p_a_r_a_m_e_t_e_r is @@ or **, the case modification operation is applied + to each positional parameter in turn, and the expansion is the + resultant list. If _p_a_r_a_m_e_t_e_r is an array variable subscripted + with @@ or **, the case modification operation is applied to each + member of the array in turn, and the expansion is the resultant + list. ${_p_a_r_a_m_e_t_e_r@@_o_p_e_r_a_t_o_r} PPaarraammeetteerr ttrraannssffoorrmmaattiioonn. The expansion is either a transforma- - tion of the value of _p_a_r_a_m_e_t_e_r or information about _p_a_r_a_m_e_t_e_r - itself, depending on the value of _o_p_e_r_a_t_o_r. Each _o_p_e_r_a_t_o_r is a + tion of the value of _p_a_r_a_m_e_t_e_r or information about _p_a_r_a_m_e_t_e_r + itself, depending on the value of _o_p_e_r_a_t_o_r. Each _o_p_e_r_a_t_o_r is a single letter: - QQ The expansion is a string that is the value of _p_a_r_a_m_e_t_e_r + UU The expansion is a string that is the value of _p_a_r_a_m_e_t_e_r + with lowercase alphabetic characters converted to upper- + case. + uu The expansion is a string that is the value of _p_a_r_a_m_e_t_e_r + with the first character converted to uppercase, if it is + alphabetic. + LL The expansion is a string that is the value of _p_a_r_a_m_e_t_e_r + with uppercase alphabetic characters converted to lower- + case. + QQ The expansion is a string that is the value of _p_a_r_a_m_e_t_e_r quoted in a format that can be reused as input. - EE The expansion is a string that is the value of _p_a_r_a_m_e_t_e_r - with backslash escape sequences expanded as with the + EE The expansion is a string that is the value of _p_a_r_a_m_e_t_e_r + with backslash escape sequences expanded as with the $$''......'' quoting mechanism. PP The expansion is a string that is the result of expanding the value of _p_a_r_a_m_e_t_e_r as if it were a prompt string (see PPRROOMMPPTTIINNGG below). - AA The expansion is a string in the form of an assignment - statement or ddeeccllaarree command that, if evaluated, will + AA The expansion is a string in the form of an assignment + statement or ddeeccllaarree command that, if evaluated, will recreate _p_a_r_a_m_e_t_e_r with its attributes and value. + KK Produces a possibly-quoted version of the value of _p_a_r_a_m_- + _e_t_e_r, except that it prints the values of indexed and as- + sociative arrays as a sequence of quoted key-value pairs + (see AArrrraayyss above). aa The expansion is a string consisting of flag values rep- resenting _p_a_r_a_m_e_t_e_r's attributes. @@ -1865,8 +1914,8 @@ EEXXPPAANNSSIIOONN $$((((_e_x_p_r_e_s_s_i_o_n)))) The _e_x_p_r_e_s_s_i_o_n is treated as if it were within double quotes, but a - double quote inside the parentheses is not treated specially. All - tokens in the expression undergo parameter and variable expansion, com- + double quote inside the parentheses is not treated specially. All to- + kens in the expression undergo parameter and variable expansion, com- mand substitution, and quote removal. The result is treated as the arithmetic expression to be evaluated. Arithmetic expansions may be nested. @@ -1913,37 +1962,37 @@ EEXXPPAANNSSIIOONN Explicit null arguments ("""" or '''') are retained and passed to commands as empty strings. Unquoted implicit null arguments, resulting from the expansion of parameters that have no values, are removed. If a parame- - ter with no value is expanded within double quotes, a null argument - results and is retained and passed to a command as an empty string. - When a quoted null argument appears as part of a word whose expansion - is non-null, the null argument is removed. That is, the word -d'' - becomes -d after word splitting and null argument removal. + ter with no value is expanded within double quotes, a null argument re- + sults and is retained and passed to a command as an empty string. When + a quoted null argument appears as part of a word whose expansion is + non-null, the null argument is removed. That is, the word -d'' becomes + -d after word splitting and null argument removal. Note that if no expansion occurs, no splitting is performed. PPaatthhnnaammee EExxppaannssiioonn After word splitting, unless the --ff option has been set, bbaasshh scans each word for the characters **, ??, and [[. If one of these characters - appears, then the word is regarded as a _p_a_t_t_e_r_n, and replaced with an - alphabetically sorted list of filenames matching the pattern (see PPaatt-- - tteerrnn MMaattcchhiinngg below). If no matching filenames are found, and the - shell option nnuullllgglloobb is not enabled, the word is left unchanged. If - the nnuullllgglloobb option is set, and no matches are found, the word is - removed. If the ffaaiillgglloobb shell option is set, and no matches are - found, an error message is printed and the command is not executed. If - the shell option nnooccaasseegglloobb is enabled, the match is performed without - regard to the case of alphabetic characters. When a pattern is used - for pathname expansion, the character ````..'''' at the start of a name or - immediately following a slash must be matched explicitly, unless the - shell option ddoottgglloobb is set. The filenames ````..'''' and ````....'''' must - always be matched explicitly, even if ddoottgglloobb is set. In other cases, - the ````..'''' character is not treated specially. When matching a path- - name, the slash character must always be matched explicitly by a slash - in the pattern, but in other matching contexts it can be matched by a - special pattern character as described below under PPaatttteerrnn MMaattcchhiinngg. - See the description of sshhoopptt below under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS for a - description of the nnooccaasseegglloobb, nnuullllgglloobb, ffaaiillgglloobb, and ddoottgglloobb shell - options. + appears, and is not quoted, then the word is regarded as a _p_a_t_t_e_r_n, and + replaced with an alphabetically sorted list of filenames matching the + pattern (see PPaatttteerrnn MMaattcchhiinngg below). If no matching filenames are + found, and the shell option nnuullllgglloobb is not enabled, the word is left + unchanged. If the nnuullllgglloobb option is set, and no matches are found, + the word is removed. If the ffaaiillgglloobb shell option is set, and no + matches are found, an error message is printed and the command is not + executed. If the shell option nnooccaasseegglloobb is enabled, the match is per- + formed without regard to the case of alphabetic characters. When a + pattern is used for pathname expansion, the character ````..'''' at the + start of a name or immediately following a slash must be matched ex- + plicitly, unless the shell option ddoottgglloobb is set. The filenames ````..'''' + and ````....'''' must always be matched explicitly, even if ddoottgglloobb is set. + In other cases, the ````..'''' character is not treated specially. When + matching a pathname, the slash character must always be matched explic- + itly by a slash in the pattern, but in other matching contexts it can + be matched by a special pattern character as described below under PPaatt-- + tteerrnn MMaattcchhiinngg. See the description of sshhoopptt below under SSHHEELLLL BBUUIILLTTIINN + CCOOMMMMAANNDDSS for a description of the nnooccaasseegglloobb, nnuullllgglloobb, ffaaiillgglloobb, and + ddoottgglloobb shell options. The GGLLOOBBIIGGNNOORREE shell variable may be used to restrict the set of file names matching a _p_a_t_t_e_r_n. If GGLLOOBBIIGGNNOORREE is set, each matching file @@ -1972,22 +2021,22 @@ EEXXPPAANNSSIIOONN ** Matches any string, including the null string. When the gglloobbssttaarr shell option is enabled, and ** is used in a pathname expansion context, two adjacent **s used as a - single pattern will match all files and zero or more - directories and subdirectories. If followed by a //, two + single pattern will match all files and zero or more di- + rectories and subdirectories. If followed by a //, two adjacent **s will match only directories and subdirecto- ries. ?? Matches any single character. [[......]] Matches any one of the enclosed characters. A pair of characters separated by a hyphen denotes a _r_a_n_g_e _e_x_p_r_e_s_- _s_i_o_n; any character that falls between those two charac- - ters, inclusive, using the current locale's collating - sequence and character set, is matched. If the first - character following the [[ is a !! or a ^^ then any charac- - ter not enclosed is matched. The sorting order of char- - acters in range expressions is determined by the current - locale and the values of the LLCC__CCOOLLLLAATTEE or LLCC__AALLLL shell - variables, if set. To obtain the traditional interpreta- - tion of range expressions, where [[aa--dd]] is equivalent to + ters, inclusive, using the current locale's collating se- + quence and character set, is matched. If the first char- + acter following the [[ is a !! or a ^^ then any character + not enclosed is matched. The sorting order of characters + in range expressions is determined by the current locale + and the values of the LLCC__CCOOLLLLAATTEE or LLCC__AALLLL shell vari- + ables, if set. To obtain the traditional interpretation + of range expressions, where [[aa--dd]] is equivalent to [[aabbccdd]], set value of the LLCC__AALLLL shell variable to CC, or enable the gglloobbaasscciiiirraannggeess shell option. A -- may be matched by including it as the first or last character in @@ -2003,10 +2052,10 @@ EEXXPPAANNSSIIOONN class. The wwoorrdd character class matches letters, digits, and the character _. - Within [[ and ]], an _e_q_u_i_v_a_l_e_n_c_e _c_l_a_s_s can be specified - using the syntax [[==_c==]], which matches all characters with - the same collation weight (as defined by the current - locale) as the character _c. + Within [[ and ]], an _e_q_u_i_v_a_l_e_n_c_e _c_l_a_s_s can be specified us- + ing the syntax [[==_c==]], which matches all characters with + the same collation weight (as defined by the current lo- + cale) as the character _c. Within [[ and ]], the syntax [[.._s_y_m_b_o_l..]] matches the collat- ing symbol _s_y_m_b_o_l. @@ -2028,71 +2077,70 @@ EEXXPPAANNSSIIOONN !!((_p_a_t_t_e_r_n_-_l_i_s_t)) Matches anything except one of the given patterns - Complicated extended pattern matching against long strings is slow, - especially when the patterns contain alternations and the strings con- - tain multiple matches. Using separate matches against shorter strings, - or using arrays of strings instead of a single long string, may be - faster. + Complicated extended pattern matching against long strings is slow, es- + pecially when the patterns contain alternations and the strings contain + multiple matches. Using separate matches against shorter strings, or + using arrays of strings instead of a single long string, may be faster. QQuuoottee RReemmoovvaall After the preceding expansions, all unquoted occurrences of the charac- - ters \\, '', and "" that did not result from one of the above expansions + ters \\, '', and "" that did not result from one of the above expansions are removed. RREEDDIIRREECCTTIIOONN - Before a command is executed, its input and output may be _r_e_d_i_r_e_c_t_e_d - using a special notation interpreted by the shell. Redirection allows - commands' file handles to be duplicated, opened, closed, made to refer + Before a command is executed, its input and output may be _r_e_d_i_r_e_c_t_e_d + using a special notation interpreted by the shell. Redirection allows + commands' file handles to be duplicated, opened, closed, made to refer to different files, and can change the files the command reads from and - writes to. Redirection may also be used to modify file handles in the - current shell execution environment. The following redirection opera- + writes to. Redirection may also be used to modify file handles in the + current shell execution environment. The following redirection opera- tors may precede or appear anywhere within a _s_i_m_p_l_e _c_o_m_m_a_n_d or may fol- - low a _c_o_m_m_a_n_d. Redirections are processed in the order they appear, + low a _c_o_m_m_a_n_d. Redirections are processed in the order they appear, from left to right. - Each redirection that may be preceded by a file descriptor number may + Each redirection that may be preceded by a file descriptor number may instead be preceded by a word of the form {_v_a_r_n_a_m_e}. In this case, for each redirection operator except >&- and <&-, the shell will allocate a - file descriptor greater than or equal to 10 and assign it to _v_a_r_n_a_m_e. - If >&- or <&- is preceded by {_v_a_r_n_a_m_e}, the value of _v_a_r_n_a_m_e defines - the file descriptor to close. If {_v_a_r_n_a_m_e} is supplied, the redirect- - ion persists beyond the scope of the command, allowing the shell pro- + file descriptor greater than or equal to 10 and assign it to _v_a_r_n_a_m_e. + If >&- or <&- is preceded by {_v_a_r_n_a_m_e}, the value of _v_a_r_n_a_m_e defines + the file descriptor to close. If {_v_a_r_n_a_m_e} is supplied, the redirect- + ion persists beyond the scope of the command, allowing the shell pro- grammer to manage the file descriptor himself. - In the following descriptions, if the file descriptor number is omit- - ted, and the first character of the redirection operator is <<, the re- - direction refers to the standard input (file descriptor 0). If the - first character of the redirection operator is >>, the redirection + In the following descriptions, if the file descriptor number is omit- + ted, and the first character of the redirection operator is <<, the re- + direction refers to the standard input (file descriptor 0). If the + first character of the redirection operator is >>, the redirection refers to the standard output (file descriptor 1). - The word following the redirection operator in the following descrip- - tions, unless otherwise noted, is subjected to brace expansion, tilde - expansion, parameter and variable expansion, command substitution, - arithmetic expansion, quote removal, pathname expansion, and word + The word following the redirection operator in the following descrip- + tions, unless otherwise noted, is subjected to brace expansion, tilde + expansion, parameter and variable expansion, command substitution, + arithmetic expansion, quote removal, pathname expansion, and word splitting. If it expands to more than one word, bbaasshh reports an error. - Note that the order of redirections is significant. For example, the + Note that the order of redirections is significant. For example, the command ls >> dirlist 2>>&&1 - directs both standard output and standard error to the file _d_i_r_l_i_s_t, + directs both standard output and standard error to the file _d_i_r_l_i_s_t, while the command ls 2>>&&1 >> dirlist - directs only the standard output to file _d_i_r_l_i_s_t, because the standard - error was duplicated from the standard output before the standard out- + directs only the standard output to file _d_i_r_l_i_s_t, because the standard + error was duplicated from the standard output before the standard out- put was redirected to _d_i_r_l_i_s_t. BBaasshh handles several filenames specially when they are used in redirec- tions, as described in the following table. If the operating system on which bbaasshh is running provides these special files, bash will use them; - otherwise it will emulate them internally with the behavior described + otherwise it will emulate them internally with the behavior described below. //ddeevv//ffdd//_f_d - If _f_d is a valid integer, file descriptor _f_d is dupli- + If _f_d is a valid integer, file descriptor _f_d is dupli- cated. //ddeevv//ssttddiinn File descriptor 0 is duplicated. @@ -2102,22 +2150,22 @@ RREEDDIIRREECCTTIIOONN File descriptor 2 is duplicated. //ddeevv//ttccpp//_h_o_s_t//_p_o_r_t If _h_o_s_t is a valid hostname or Internet address, and _p_o_r_t - is an integer port number or service name, bbaasshh attempts + is an integer port number or service name, bbaasshh attempts to open the corresponding TCP socket. //ddeevv//uuddpp//_h_o_s_t//_p_o_r_t If _h_o_s_t is a valid hostname or Internet address, and _p_o_r_t - is an integer port number or service name, bbaasshh attempts + is an integer port number or service name, bbaasshh attempts to open the corresponding UDP socket. A failure to open or create a file causes the redirection to fail. - Redirections using file descriptors greater than 9 should be used with - care, as they may conflict with file descriptors the shell uses inter- + Redirections using file descriptors greater than 9 should be used with + care, as they may conflict with file descriptors the shell uses inter- nally. RReeddiirreeccttiinngg IInnppuutt Redirection of input causes the file whose name results from the expan- - sion of _w_o_r_d to be opened for reading on file descriptor _n, or the + sion of _w_o_r_d to be opened for reading on file descriptor _n, or the standard input (file descriptor 0) if _n is not specified. The general format for redirecting input is: @@ -2125,27 +2173,27 @@ RREEDDIIRREECCTTIIOONN [_n]<<_w_o_r_d RReeddiirreeccttiinngg OOuuttppuutt - Redirection of output causes the file whose name results from the - expansion of _w_o_r_d to be opened for writing on file descriptor _n, or the + Redirection of output causes the file whose name results from the ex- + pansion of _w_o_r_d to be opened for writing on file descriptor _n, or the standard output (file descriptor 1) if _n is not specified. If the file - does not exist it is created; if it does exist it is truncated to zero + does not exist it is created; if it does exist it is truncated to zero size. The general format for redirecting output is: [_n]>>_w_o_r_d - If the redirection operator is >>, and the nnoocclloobbbbeerr option to the sseett - builtin has been enabled, the redirection will fail if the file whose - name results from the expansion of _w_o_r_d exists and is a regular file. + If the redirection operator is >>, and the nnoocclloobbbbeerr option to the sseett + builtin has been enabled, the redirection will fail if the file whose + name results from the expansion of _w_o_r_d exists and is a regular file. If the redirection operator is >>||, or the redirection operator is >> and the nnoocclloobbbbeerr option to the sseett builtin command is not enabled, the re- direction is attempted even if the file named by _w_o_r_d exists. AAppppeennddiinngg RReeddiirreecctteedd OOuuttppuutt - Redirection of output in this fashion causes the file whose name - results from the expansion of _w_o_r_d to be opened for appending on file - descriptor _n, or the standard output (file descriptor 1) if _n is not + Redirection of output in this fashion causes the file whose name re- + sults from the expansion of _w_o_r_d to be opened for appending on file de- + scriptor _n, or the standard output (file descriptor 1) if _n is not specified. If the file does not exist it is created. The general format for appending output is: @@ -2153,12 +2201,12 @@ RREEDDIIRREECCTTIIOONN [_n]>>>>_w_o_r_d RReeddiirreeccttiinngg SSttaannddaarrdd OOuuttppuutt aanndd SSttaannddaarrdd EErrrroorr - This construct allows both the standard output (file descriptor 1) and - the standard error output (file descriptor 2) to be redirected to the + This construct allows both the standard output (file descriptor 1) and + the standard error output (file descriptor 2) to be redirected to the file whose name is the expansion of _w_o_r_d. - There are two formats for redirecting standard output and standard - error: + There are two formats for redirecting standard output and standard er- + ror: &&>>_w_o_r_d and @@ -2169,13 +2217,13 @@ RREEDDIIRREECCTTIIOONN >>_w_o_r_d 2>>&&1 - When using the second form, _w_o_r_d may not expand to a number or --. If - it does, other redirection operators apply (see DDuupplliiccaattiinngg FFiillee - DDeessccrriippttoorrss below) for compatibility reasons. + When using the second form, _w_o_r_d may not expand to a number or --. If + it does, other redirection operators apply (see DDuupplliiccaattiinngg FFiillee DDee-- + ssccrriippttoorrss below) for compatibility reasons. AAppppeennddiinngg SSttaannddaarrdd OOuuttppuutt aanndd SSttaannddaarrdd EErrrroorr - This construct allows both the standard output (file descriptor 1) and - the standard error output (file descriptor 2) to be appended to the + This construct allows both the standard output (file descriptor 1) and + the standard error output (file descriptor 2) to be appended to the file whose name is the expansion of _w_o_r_d. The format for appending standard output and standard error is: @@ -2189,10 +2237,10 @@ RREEDDIIRREECCTTIIOONN (see DDuupplliiccaattiinngg FFiillee DDeessccrriippttoorrss below). HHeerree DDooccuummeennttss - This type of redirection instructs the shell to read input from the + This type of redirection instructs the shell to read input from the current source until a line containing only _d_e_l_i_m_i_t_e_r (with no trailing - blanks) is seen. All of the lines read up to that point are then used - as the standard input (or file descriptor _n if _n is specified) for a + blanks) is seen. All of the lines read up to that point are then used + as the standard input (or file descriptor _n if _n is specified) for a command. The format of here-documents is: @@ -2201,18 +2249,18 @@ RREEDDIIRREECCTTIIOONN _h_e_r_e_-_d_o_c_u_m_e_n_t _d_e_l_i_m_i_t_e_r - No parameter and variable expansion, command substitution, arithmetic - expansion, or pathname expansion is performed on _w_o_r_d. If any part of - _w_o_r_d is quoted, the _d_e_l_i_m_i_t_e_r is the result of quote removal on _w_o_r_d, - and the lines in the here-document are not expanded. If _w_o_r_d is - unquoted, all lines of the here-document are subjected to parameter - expansion, command substitution, and arithmetic expansion, the charac- - ter sequence \\<<nneewwlliinnee>> is ignored, and \\ must be used to quote the - characters \\, $$, and ``. + No parameter and variable expansion, command substitution, arithmetic + expansion, or pathname expansion is performed on _w_o_r_d. If any part of + _w_o_r_d is quoted, the _d_e_l_i_m_i_t_e_r is the result of quote removal on _w_o_r_d, + and the lines in the here-document are not expanded. If _w_o_r_d is un- + quoted, all lines of the here-document are subjected to parameter ex- + pansion, command substitution, and arithmetic expansion, the character + sequence \\<<nneewwlliinnee>> is ignored, and \\ must be used to quote the charac- + ters \\, $$, and ``. If the redirection operator is <<<<--, then all leading tab characters are - stripped from input lines and the line containing _d_e_l_i_m_i_t_e_r. This - allows here-documents within shell scripts to be indented in a natural + stripped from input lines and the line containing _d_e_l_i_m_i_t_e_r. This al- + lows here-documents within shell scripts to be indented in a natural fashion. HHeerree SSttrriinnggss @@ -2220,9 +2268,9 @@ RREEDDIIRREECCTTIIOONN [_n]<<<<<<_w_o_r_d - The _w_o_r_d undergoes tilde expansion, parameter and variable expansion, - command substitution, arithmetic expansion, and quote removal. Path- - name expansion and word splitting are not performed. The result is + The _w_o_r_d undergoes tilde expansion, parameter and variable expansion, + command substitution, arithmetic expansion, and quote removal. Path- + name expansion and word splitting are not performed. The result is supplied as a single string, with a newline appended, to the command on its standard input (or file descriptor _n if _n is specified). @@ -2232,22 +2280,22 @@ RREEDDIIRREECCTTIIOONN [_n]<<&&_w_o_r_d is used to duplicate input file descriptors. If _w_o_r_d expands to one or - more digits, the file descriptor denoted by _n is made to be a copy of - that file descriptor. If the digits in _w_o_r_d do not specify a file - descriptor open for input, a redirection error occurs. If _w_o_r_d evalu- - ates to --, file descriptor _n is closed. If _n is not specified, the - standard input (file descriptor 0) is used. + more digits, the file descriptor denoted by _n is made to be a copy of + that file descriptor. If the digits in _w_o_r_d do not specify a file de- + scriptor open for input, a redirection error occurs. If _w_o_r_d evaluates + to --, file descriptor _n is closed. If _n is not specified, the standard + input (file descriptor 0) is used. The operator [_n]>>&&_w_o_r_d - is used similarly to duplicate output file descriptors. If _n is not - specified, the standard output (file descriptor 1) is used. If the - digits in _w_o_r_d do not specify a file descriptor open for output, a re- - direction error occurs. If _w_o_r_d evaluates to --, file descriptor _n is - closed. As a special case, if _n is omitted, and _w_o_r_d does not expand - to one or more digits or --, the standard output and standard error are + is used similarly to duplicate output file descriptors. If _n is not + specified, the standard output (file descriptor 1) is used. If the + digits in _w_o_r_d do not specify a file descriptor open for output, a re- + direction error occurs. If _w_o_r_d evaluates to --, file descriptor _n is + closed. As a special case, if _n is omitted, and _w_o_r_d does not expand + to one or more digits or --, the standard output and standard error are redirected as described previously. MMoovviinngg FFiillee DDeessccrriippttoorrss @@ -2255,7 +2303,7 @@ RREEDDIIRREECCTTIIOONN [_n]<<&&_d_i_g_i_t-- - moves the file descriptor _d_i_g_i_t to file descriptor _n, or the standard + moves the file descriptor _d_i_g_i_t to file descriptor _n, or the standard input (file descriptor 0) if _n is not specified. _d_i_g_i_t is closed after being duplicated to _n. @@ -2263,7 +2311,7 @@ RREEDDIIRREECCTTIIOONN [_n]>>&&_d_i_g_i_t-- - moves the file descriptor _d_i_g_i_t to file descriptor _n, or the standard + moves the file descriptor _d_i_g_i_t to file descriptor _n, or the standard output (file descriptor 1) if _n is not specified. OOppeenniinngg FFiillee DDeessccrriippttoorrss ffoorr RReeaaddiinngg aanndd WWrriittiinngg @@ -2271,146 +2319,146 @@ RREEDDIIRREECCTTIIOONN [_n]<<>>_w_o_r_d - causes the file whose name is the expansion of _w_o_r_d to be opened for - both reading and writing on file descriptor _n, or on file descriptor 0 + causes the file whose name is the expansion of _w_o_r_d to be opened for + both reading and writing on file descriptor _n, or on file descriptor 0 if _n is not specified. If the file does not exist, it is created. AALLIIAASSEESS - _A_l_i_a_s_e_s allow a string to be substituted for a word when it is used as - the first word of a simple command. The shell maintains a list of - aliases that may be set and unset with the aalliiaass and uunnaalliiaass builtin - commands (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). The first word of each - simple command, if unquoted, is checked to see if it has an alias. If - so, that word is replaced by the text of the alias. The characters //, - $$, ``, and == and any of the shell _m_e_t_a_c_h_a_r_a_c_t_e_r_s or quoting characters + _A_l_i_a_s_e_s allow a string to be substituted for a word when it is used as + the first word of a simple command. The shell maintains a list of + aliases that may be set and unset with the aalliiaass and uunnaalliiaass builtin + commands (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). The first word of each + simple command, if unquoted, is checked to see if it has an alias. If + so, that word is replaced by the text of the alias. The characters //, + $$, ``, and == and any of the shell _m_e_t_a_c_h_a_r_a_c_t_e_r_s or quoting characters listed above may not appear in an alias name. The replacement text may - contain any valid shell input, including shell metacharacters. The - first word of the replacement text is tested for aliases, but a word - that is identical to an alias being expanded is not expanded a second - time. This means that one may alias llss to llss --FF, for instance, and - bbaasshh does not try to recursively expand the replacement text. If the - last character of the alias value is a _b_l_a_n_k, then the next command + contain any valid shell input, including shell metacharacters. The + first word of the replacement text is tested for aliases, but a word + that is identical to an alias being expanded is not expanded a second + time. This means that one may alias llss to llss --FF, for instance, and + bbaasshh does not try to recursively expand the replacement text. If the + last character of the alias value is a _b_l_a_n_k, then the next command word following the alias is also checked for alias expansion. Aliases are created and listed with the aalliiaass command, and removed with the uunnaalliiaass command. - There is no mechanism for using arguments in the replacement text. If - arguments are needed, a shell function should be used (see FFUUNNCCTTIIOONNSS + There is no mechanism for using arguments in the replacement text. If + arguments are needed, a shell function should be used (see FFUUNNCCTTIIOONNSS below). - Aliases are not expanded when the shell is not interactive, unless the - eexxppaanndd__aalliiaasseess shell option is set using sshhoopptt (see the description of + Aliases are not expanded when the shell is not interactive, unless the + eexxppaanndd__aalliiaasseess shell option is set using sshhoopptt (see the description of sshhoopptt under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - The rules concerning the definition and use of aliases are somewhat - confusing. BBaasshh always reads at least one complete line of input, and - all lines that make up a compound command, before executing any of the - commands on that line or the compound command. Aliases are expanded - when a command is read, not when it is executed. Therefore, an alias - definition appearing on the same line as another command does not take - effect until the next line of input is read. The commands following - the alias definition on that line are not affected by the new alias. - This behavior is also an issue when functions are executed. Aliases - are expanded when a function definition is read, not when the function - is executed, because a function definition is itself a command. As a - consequence, aliases defined in a function are not available until - after that function is executed. To be safe, always put alias defini- + The rules concerning the definition and use of aliases are somewhat + confusing. BBaasshh always reads at least one complete line of input, and + all lines that make up a compound command, before executing any of the + commands on that line or the compound command. Aliases are expanded + when a command is read, not when it is executed. Therefore, an alias + definition appearing on the same line as another command does not take + effect until the next line of input is read. The commands following + the alias definition on that line are not affected by the new alias. + This behavior is also an issue when functions are executed. Aliases + are expanded when a function definition is read, not when the function + is executed, because a function definition is itself a command. As a + consequence, aliases defined in a function are not available until af- + ter that function is executed. To be safe, always put alias defini- tions on a separate line, and do not use aalliiaass in compound commands. For almost every purpose, aliases are superseded by shell functions. FFUUNNCCTTIIOONNSS - A shell function, defined as described above under SSHHEELLLL GGRRAAMMMMAARR, - stores a series of commands for later execution. When the name of a - shell function is used as a simple command name, the list of commands + A shell function, defined as described above under SSHHEELLLL GGRRAAMMMMAARR, + stores a series of commands for later execution. When the name of a + shell function is used as a simple command name, the list of commands associated with that function name is executed. Functions are executed - in the context of the current shell; no new process is created to - interpret them (contrast this with the execution of a shell script). - When a function is executed, the arguments to the function become the + in the context of the current shell; no new process is created to in- + terpret them (contrast this with the execution of a shell script). + When a function is executed, the arguments to the function become the positional parameters during its execution. The special parameter ## is - updated to reflect the change. Special parameter 00 is unchanged. The - first element of the FFUUNNCCNNAAMMEE variable is set to the name of the func- + updated to reflect the change. Special parameter 00 is unchanged. The + first element of the FFUUNNCCNNAAMMEE variable is set to the name of the func- tion while the function is executing. - All other aspects of the shell execution environment are identical - between a function and its caller with these exceptions: the DDEEBBUUGG and - RREETTUURRNN traps (see the description of the ttrraapp builtin under SSHHEELLLL - BBUUIILLTTIINN CCOOMMMMAANNDDSS below) are not inherited unless the function has been - given the ttrraaccee attribute (see the description of the ddeeccllaarree builtin - below) or the --oo ffuunnccttrraaccee shell option has been enabled with the sseett - builtin (in which case all functions inherit the DDEEBBUUGG and RREETTUURRNN - traps), and the EERRRR trap is not inherited unless the --oo eerrrrttrraaccee shell + All other aspects of the shell execution environment are identical be- + tween a function and its caller with these exceptions: the DDEEBBUUGG and + RREETTUURRNN traps (see the description of the ttrraapp builtin under SSHHEELLLL + BBUUIILLTTIINN CCOOMMMMAANNDDSS below) are not inherited unless the function has been + given the ttrraaccee attribute (see the description of the ddeeccllaarree builtin + below) or the --oo ffuunnccttrraaccee shell option has been enabled with the sseett + builtin (in which case all functions inherit the DDEEBBUUGG and RREETTUURRNN + traps), and the EERRRR trap is not inherited unless the --oo eerrrrttrraaccee shell option has been enabled. - Variables local to the function may be declared with the llooccaall builtin + Variables local to the function may be declared with the llooccaall builtin command. Ordinarily, variables and their values are shared between the - function and its caller. If a variable is declared llooccaall, the vari- - able's visible scope is restricted to that function and its children + function and its caller. If a variable is declared llooccaall, the vari- + able's visible scope is restricted to that function and its children (including the functions it calls). Local variables "shadow" variables - with the same name declared at previous scopes. For instance, a local - variable declared in a function hides a global variable of the same - name: references and assignments refer to the local variable, leaving - the global variable unmodified. When the function returns, the global + with the same name declared at previous scopes. For instance, a local + variable declared in a function hides a global variable of the same + name: references and assignments refer to the local variable, leaving + the global variable unmodified. When the function returns, the global variable is once again visible. - The shell uses _d_y_n_a_m_i_c _s_c_o_p_i_n_g to control a variable's visibility - within functions. With dynamic scoping, visible variables and their - values are a result of the sequence of function calls that caused exe- - cution to reach the current function. The value of a variable that a - function sees depends on its value within its caller, if any, whether - that caller is the "global" scope or another shell function. This is - also the value that a local variable declaration "shadows", and the + The shell uses _d_y_n_a_m_i_c _s_c_o_p_i_n_g to control a variable's visibility + within functions. With dynamic scoping, visible variables and their + values are a result of the sequence of function calls that caused exe- + cution to reach the current function. The value of a variable that a + function sees depends on its value within its caller, if any, whether + that caller is the "global" scope or another shell function. This is + also the value that a local variable declaration "shadows", and the value that is restored when the function returns. - For example, if a variable _v_a_r is declared as local in function _f_u_n_c_1, - and _f_u_n_c_1 calls another function _f_u_n_c_2, references to _v_a_r made from + For example, if a variable _v_a_r is declared as local in function _f_u_n_c_1, + and _f_u_n_c_1 calls another function _f_u_n_c_2, references to _v_a_r made from within _f_u_n_c_2 will resolve to the local variable _v_a_r from _f_u_n_c_1, shadow- ing any global variable named _v_a_r. The uunnsseett builtin also acts using the same dynamic scope: if a variable is local to the current scope, uunnsseett will unset it; otherwise the unset - will refer to the variable found in any calling scope as described - above. If a variable at the current local scope is unset, it will - remain so until it is reset in that scope or until the function - returns. Once the function returns, any instance of the variable at a - previous scope will become visible. If the unset acts on a variable at - a previous scope, any instance of a variable with that name that had - been shadowed will become visible. - - The FFUUNNCCNNEESSTT variable, if set to a numeric value greater than 0, - defines a maximum function nesting level. Function invocations that - exceed the limit cause the entire command to abort. - - If the builtin command rreettuurrnn is executed in a function, the function - completes and execution resumes with the next command after the func- - tion call. Any command associated with the RREETTUURRNN trap is executed - before execution resumes. When a function completes, the values of the - positional parameters and the special parameter ## are restored to the + will refer to the variable found in any calling scope as described + above. If a variable at the current local scope is unset, it will re- + main so until it is reset in that scope or until the function returns. + Once the function returns, any instance of the variable at a previous + scope will become visible. If the unset acts on a variable at a previ- + ous scope, any instance of a variable with that name that had been + shadowed will become visible. + + The FFUUNNCCNNEESSTT variable, if set to a numeric value greater than 0, de- + fines a maximum function nesting level. Function invocations that ex- + ceed the limit cause the entire command to abort. + + If the builtin command rreettuurrnn is executed in a function, the function + completes and execution resumes with the next command after the func- + tion call. Any command associated with the RREETTUURRNN trap is executed be- + fore execution resumes. When a function completes, the values of the + positional parameters and the special parameter ## are restored to the values they had prior to the function's execution. - Function names and definitions may be listed with the --ff option to the + Function names and definitions may be listed with the --ff option to the ddeeccllaarree or ttyyppeesseett builtin commands. The --FF option to ddeeccllaarree or ttyyppee-- - sseett will list the function names only (and optionally the source file - and line number, if the eexxttddeebbuugg shell option is enabled). Functions - may be exported so that subshells automatically have them defined with - the --ff option to the eexxppoorrtt builtin. A function definition may be + sseett will list the function names only (and optionally the source file + and line number, if the eexxttddeebbuugg shell option is enabled). Functions + may be exported so that subshells automatically have them defined with + the --ff option to the eexxppoorrtt builtin. A function definition may be deleted using the --ff option to the uunnsseett builtin. Functions may be recursive. The FFUUNNCCNNEESSTT variable may be used to limit - the depth of the function call stack and restrict the number of func- - tion invocations. By default, no limit is imposed on the number of - recursive calls. + the depth of the function call stack and restrict the number of func- + tion invocations. By default, no limit is imposed on the number of re- + cursive calls. AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN - The shell allows arithmetic expressions to be evaluated, under certain - circumstances (see the lleett and ddeeccllaarree builtin commands, the (((( com- + The shell allows arithmetic expressions to be evaluated, under certain + circumstances (see the lleett and ddeeccllaarree builtin commands, the (((( com- pound command, and AArriitthhmmeettiicc EExxppaannssiioonn). Evaluation is done in fixed- - width integers with no check for overflow, though division by 0 is - trapped and flagged as an error. The operators and their precedence, - associativity, and values are the same as in the C language. The fol- - lowing list of operators is grouped into levels of equal-precedence - operators. The levels are listed in order of decreasing precedence. + width integers with no check for overflow, though division by 0 is + trapped and flagged as an error. The operators and their precedence, + associativity, and values are the same as in the C language. The fol- + lowing list of operators is grouped into levels of equal-precedence op- + erators. The levels are listed in order of decreasing precedence. _i_d++++ _i_d---- variable post-increment and post-decrement @@ -2437,53 +2485,55 @@ AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN _e_x_p_r_1 ,, _e_x_p_r_2 comma - Shell variables are allowed as operands; parameter expansion is per- + Shell variables are allowed as operands; parameter expansion is per- formed before the expression is evaluated. Within an expression, shell - variables may also be referenced by name without using the parameter - expansion syntax. A shell variable that is null or unset evaluates to + variables may also be referenced by name without using the parameter + expansion syntax. A shell variable that is null or unset evaluates to 0 when referenced by name without using the parameter expansion syntax. - The value of a variable is evaluated as an arithmetic expression when - it is referenced, or when a variable which has been given the _i_n_t_e_g_e_r + The value of a variable is evaluated as an arithmetic expression when + it is referenced, or when a variable which has been given the _i_n_t_e_g_e_r attribute using ddeeccllaarree --ii is assigned a value. A null value evaluates - to 0. A shell variable need not have its _i_n_t_e_g_e_r attribute turned on + to 0. A shell variable need not have its _i_n_t_e_g_e_r attribute turned on to be used in an expression. - Constants with a leading 0 are interpreted as octal numbers. A leading - 0x or 0X denotes hexadecimal. Otherwise, numbers take the form - [_b_a_s_e_#]n, where the optional _b_a_s_e is a decimal number between 2 and 64 - representing the arithmetic base, and _n is a number in that base. If - _b_a_s_e_# is omitted, then base 10 is used. When specifying _n, the digits - greater than 9 are represented by the lowercase letters, the uppercase - letters, @, and _, in that order. If _b_a_s_e is less than or equal to 36, - lowercase and uppercase letters may be used interchangeably to repre- - sent numbers between 10 and 35. - - Operators are evaluated in order of precedence. Sub-expressions in - parentheses are evaluated first and may override the precedence rules + Integer constants follow the C language definition, without suffixes or + character constants. Constants with a leading 0 are interpreted as oc- + tal numbers. A leading 0x or 0X denotes hexadecimal. Otherwise, num- + bers take the form [_b_a_s_e_#]n, where the optional _b_a_s_e is a decimal num- + ber between 2 and 64 representing the arithmetic base, and _n is a num- + ber in that base. If _b_a_s_e_# is omitted, then base 10 is used. When + specifying _n, if a non-digit is required, the digits greater than 9 are + represented by the lowercase letters, the uppercase letters, @, and _, + in that order. If _b_a_s_e is less than or equal to 36, lowercase and up- + percase letters may be used interchangeably to represent numbers be- + tween 10 and 35. + + Operators are evaluated in order of precedence. Sub-expressions in + parentheses are evaluated first and may override the precedence rules above. CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS - Conditional expressions are used by the [[[[ compound command and the - tteesstt and [[ builtin commands to test file attributes and perform string - and arithmetic comparisons. The tteesstt abd [[ commands determine their - behavior based on the number of arguments; see the descriptions of + Conditional expressions are used by the [[[[ compound command and the + tteesstt and [[ builtin commands to test file attributes and perform string + and arithmetic comparisons. The tteesstt and [[ commands determine their + behavior based on the number of arguments; see the descriptions of those commands for any other command-specific actions. - Expressions are formed from the following unary or binary primaries. - BBaasshh handles several filenames specially when they are used in expres- + Expressions are formed from the following unary or binary primaries. + BBaasshh handles several filenames specially when they are used in expres- sions. If the operating system on which bbaasshh is running provides these - special files, bash will use them; otherwise it will emulate them - internally with this behavior: If any _f_i_l_e argument to one of the pri- + special files, bash will use them; otherwise it will emulate them in- + ternally with this behavior: If any _f_i_l_e argument to one of the pri- maries is of the form _/_d_e_v_/_f_d_/_n, then file descriptor _n is checked. If - the _f_i_l_e argument to one of the primaries is one of _/_d_e_v_/_s_t_d_i_n, - _/_d_e_v_/_s_t_d_o_u_t, or _/_d_e_v_/_s_t_d_e_r_r, file descriptor 0, 1, or 2, respectively, + the _f_i_l_e argument to one of the primaries is one of _/_d_e_v_/_s_t_d_i_n, + _/_d_e_v_/_s_t_d_o_u_t, or _/_d_e_v_/_s_t_d_e_r_r, file descriptor 0, 1, or 2, respectively, is checked. Unless otherwise specified, primaries that operate on files follow sym- bolic links and operate on the target of the link, rather than the link itself. - When used with [[[[, the << and >> operators sort lexicographically using + When used with [[[[, the << and >> operators sort lexicographically using the current locale. The tteesstt command sorts using ASCII ordering. --aa _f_i_l_e @@ -2522,30 +2572,30 @@ CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS --LL _f_i_l_e True if _f_i_l_e exists and is a symbolic link. --NN _f_i_l_e - True if _f_i_l_e exists and has been modified since it was last + True if _f_i_l_e exists and has been modified since it was last read. --OO _f_i_l_e True if _f_i_l_e exists and is owned by the effective user id. --SS _f_i_l_e True if _f_i_l_e exists and is a socket. _f_i_l_e_1 --eeff _f_i_l_e_2 - True if _f_i_l_e_1 and _f_i_l_e_2 refer to the same device and inode num- + True if _f_i_l_e_1 and _f_i_l_e_2 refer to the same device and inode num- bers. _f_i_l_e_1 -nntt _f_i_l_e_2 - True if _f_i_l_e_1 is newer (according to modification date) than + True if _f_i_l_e_1 is newer (according to modification date) than _f_i_l_e_2, or if _f_i_l_e_1 exists and _f_i_l_e_2 does not. _f_i_l_e_1 -oott _f_i_l_e_2 - True if _f_i_l_e_1 is older than _f_i_l_e_2, or if _f_i_l_e_2 exists and _f_i_l_e_1 + True if _f_i_l_e_1 is older than _f_i_l_e_2, or if _f_i_l_e_2 exists and _f_i_l_e_1 does not. --oo _o_p_t_n_a_m_e - True if the shell option _o_p_t_n_a_m_e is enabled. See the list of - options under the description of the --oo option to the sseett + True if the shell option _o_p_t_n_a_m_e is enabled. See the list of + options under the description of the --oo option to the sseett builtin below. --vv _v_a_r_n_a_m_e - True if the shell variable _v_a_r_n_a_m_e is set (has been assigned a + True if the shell variable _v_a_r_n_a_m_e is set (has been assigned a value). --RR _v_a_r_n_a_m_e - True if the shell variable _v_a_r_n_a_m_e is set and is a name refer- + True if the shell variable _v_a_r_n_a_m_e is set and is a name refer- ence. --zz _s_t_r_i_n_g True if the length of _s_t_r_i_n_g is zero. @@ -2555,8 +2605,8 @@ CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS _s_t_r_i_n_g_1 ==== _s_t_r_i_n_g_2 _s_t_r_i_n_g_1 == _s_t_r_i_n_g_2 - True if the strings are equal. == should be used with the tteesstt - command for POSIX conformance. When used with the [[[[ command, + True if the strings are equal. == should be used with the tteesstt + command for POSIX conformance. When used with the [[[[ command, this performs pattern matching as described above (CCoommppoouunndd CCoomm-- mmaannddss). @@ -2570,17 +2620,18 @@ CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS True if _s_t_r_i_n_g_1 sorts after _s_t_r_i_n_g_2 lexicographically. _a_r_g_1 OOPP _a_r_g_2 - OOPP is one of --eeqq, --nnee, --lltt, --llee, --ggtt, or --ggee. These arithmetic - binary operators return true if _a_r_g_1 is equal to, not equal to, - less than, less than or equal to, greater than, or greater than - or equal to _a_r_g_2, respectively. _A_r_g_1 and _a_r_g_2 may be positive - or negative integers. When used with the [[[[ command, _A_r_g_1 and - _A_r_g_2 are evaluated as arithmetic expressions (see AARRIITTHHMMEETTIICC + OOPP is one of --eeqq, --nnee, --lltt, --llee, --ggtt, or --ggee. These arithmetic + binary operators return true if _a_r_g_1 is equal to, not equal to, + less than, less than or equal to, greater than, or greater than + or equal to _a_r_g_2, respectively. _A_r_g_1 and _a_r_g_2 may be positive + or negative integers. When used with the [[[[ command, _A_r_g_1 and + _A_r_g_2 are evaluated as arithmetic expressions (see AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN above). SSIIMMPPLLEE CCOOMMMMAANNDD EEXXPPAANNSSIIOONN - When a simple command is executed, the shell performs the following - expansions, assignments, and redirections, from left to right. + When a simple command is executed, the shell performs the following ex- + pansions, assignments, and redirections, from left to right, in the + following order. 1. The words that the parser has marked as variable assignments (those preceding the command name) and redirections are saved @@ -2605,8 +2656,8 @@ SSIIMMPPLLEE CCOOMMMMAANNDD EEXXPPAANNSSIIOONN readonly variable, an error occurs, and the command exits with a non- zero status. - If no command name results, redirections are performed, but do not - affect the current shell environment. A redirection error causes the + If no command name results, redirections are performed, but do not af- + fect the current shell environment. A redirection error causes the command to exit with a non-zero status. If there is a command name left after expansion, execution proceeds as @@ -2629,8 +2680,8 @@ CCOOMMMMAANNDD EEXXEECCUUTTIIOONN If the name is neither a shell function nor a builtin, and contains no slashes, bbaasshh searches each element of the PPAATTHH for a directory con- - taining an executable file by that name. BBaasshh uses a hash table to - remember the full pathnames of executable files (see hhaasshh under SSHHEELLLL + taining an executable file by that name. BBaasshh uses a hash table to re- + member the full pathnames of executable files (see hhaasshh under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). A full search of the directories in PPAATTHH is performed only if the command is not found in the hash table. If the search is unsuccessful, the shell searches for a defined shell function @@ -2651,8 +2702,8 @@ CCOOMMMMAANNDD EEXXEECCUUTTIIOONN file containing shell commands. A subshell is spawned to execute it. This subshell reinitializes itself, so that the effect is as if a new shell had been invoked to handle the script, with the exception that - the locations of commands remembered by the parent (see hhaasshh below - under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS) are retained by the child. + the locations of commands remembered by the parent (see hhaasshh below un- + der SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS) are retained by the child. If the program is a file beginning with ##!!, the remainder of the first line specifies an interpreter for the program. The shell executes the @@ -2717,8 +2768,8 @@ CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENN Command substitution, commands grouped with parentheses, and asynchro- nous commands are invoked in a subshell environment that is a duplicate - of the shell environment, except that traps caught by the shell are - reset to the values that the shell inherited from its parent at invoca- + of the shell environment, except that traps caught by the shell are re- + set to the values that the shell inherited from its parent at invoca- tion. Builtin commands that are invoked as part of a pipeline are also executed in a subshell environment. Changes made to the subshell envi- ronment cannot affect the shell's execution environment. @@ -2727,24 +2778,24 @@ CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENN the --ee option from the parent shell. When not in _p_o_s_i_x _m_o_d_e, bbaasshh clears the --ee option in such subshells. - If a command is followed by a && and job control is not active, the - default standard input for the command is the empty file _/_d_e_v_/_n_u_l_l. - Otherwise, the invoked command inherits the file descriptors of the - calling shell as modified by redirections. + If a command is followed by a && and job control is not active, the de- + fault standard input for the command is the empty file _/_d_e_v_/_n_u_l_l. Oth- + erwise, the invoked command inherits the file descriptors of the call- + ing shell as modified by redirections. EENNVVIIRROONNMMEENNTT When a program is invoked it is given an array of strings called the _e_n_v_i_r_o_n_m_e_n_t. This is a list of _n_a_m_e-_v_a_l_u_e pairs, of the form _n_a_m_e=_v_a_l_u_e. - The shell provides several ways to manipulate the environment. On - invocation, the shell scans its own environment and creates a parameter + The shell provides several ways to manipulate the environment. On in- + vocation, the shell scans its own environment and creates a parameter for each name found, automatically marking it for _e_x_p_o_r_t to child pro- - cesses. Executed commands inherit the environment. The eexxppoorrtt and - ddeeccllaarree --xx commands allow parameters and functions to be added to and + cesses. Executed commands inherit the environment. The eexxppoorrtt and ddee-- + ccllaarree --xx commands allow parameters and functions to be added to and deleted from the environment. If the value of a parameter in the envi- - ronment is modified, the new value becomes part of the environment, - replacing the old. The environment inherited by any executed command + ronment is modified, the new value becomes part of the environment, re- + placing the old. The environment inherited by any executed command consists of the shell's initial environment, whose values may be modi- fied in the shell, less any pairs removed by the uunnsseett command, plus any additions via the eexxppoorrtt and ddeeccllaarree --xx commands. @@ -2775,8 +2826,8 @@ EEXXIITT SSTTAATTUUSS exit status indicates failure. When a command terminates on a fatal signal _N, bbaasshh uses the value of 128+_N as the exit status. - If a command is not found, the child process created to execute it - returns a status of 127. If a command is found but is not executable, + If a command is not found, the child process created to execute it re- + turns a status of 127. If a command is found but is not executable, the return status is 126. If a command fails because of an error during expansion or redirection, @@ -2784,23 +2835,23 @@ EEXXIITT SSTTAATTUUSS Shell builtin commands return a status of 0 (_t_r_u_e) if successful, and non-zero (_f_a_l_s_e) if an error occurs while they execute. All builtins - return an exit status of 2 to indicate incorrect usage, generally - invalid options or missing arguments. + return an exit status of 2 to indicate incorrect usage, generally in- + valid options or missing arguments. - BBaasshh itself returns the exit status of the last command executed, - unless a syntax error occurs, in which case it exits with a non-zero + BBaasshh itself returns the exit status of the last command executed, un- + less a syntax error occurs, in which case it exits with a non-zero value. See also the eexxiitt builtin command below. SSIIGGNNAALLSS When bbaasshh is interactive, in the absence of any traps, it ignores SSIIGGTTEERRMM (so that kkiillll 00 does not kill an interactive shell), and SSIIGGIINNTT is caught and handled (so that the wwaaiitt builtin is interruptible). In - all cases, bbaasshh ignores SSIIGGQQUUIITT. If job control is in effect, bbaasshh - ignores SSIIGGTTTTIINN, SSIIGGTTTTOOUU, and SSIIGGTTSSTTPP. + all cases, bbaasshh ignores SSIIGGQQUUIITT. If job control is in effect, bbaasshh ig- + nores SSIIGGTTTTIINN, SSIIGGTTTTOOUU, and SSIIGGTTSSTTPP. Non-builtin commands run by bbaasshh have signal handlers set to the values - inherited by the shell from its parent. When job control is not in - effect, asynchronous commands ignore SSIIGGIINNTT and SSIIGGQQUUIITT in addition to + inherited by the shell from its parent. When job control is not in ef- + fect, asynchronous commands ignore SSIIGGIINNTT and SSIIGGQQUUIITT in addition to these inherited handlers. Commands run as a result of command substi- tution ignore the keyboard-generated job control signals SSIIGGTTTTIINN, SSIIGGTT-- TTOOUU, and SSIIGGTTSSTTPP. @@ -2810,8 +2861,8 @@ SSIIGGNNAALLSS stopped. Stopped jobs are sent SSIIGGCCOONNTT to ensure that they receive the SSIIGGHHUUPP. To prevent the shell from sending the signal to a particular job, it should be removed from the jobs table with the ddiissoowwnn builtin - (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below) or marked to not receive SSIIGGHHUUPP - using ddiissoowwnn --hh. + (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below) or marked to not receive SSIIGGHHUUPP us- + ing ddiissoowwnn --hh. If the hhuuppoonneexxiitt shell option has been set with sshhoopptt, bbaasshh sends a SSIIGGHHUUPP to all jobs when an interactive login shell exits. @@ -2824,10 +2875,10 @@ SSIIGGNNAALLSS tus greater than 128, immediately after which the trap is executed. JJOOBB CCOONNTTRROOLL - _J_o_b _c_o_n_t_r_o_l refers to the ability to selectively stop (_s_u_s_p_e_n_d) the - execution of processes and continue (_r_e_s_u_m_e) their execution at a later - point. A user typically employs this facility via an interactive - interface supplied jointly by the operating system kernel's terminal + _J_o_b _c_o_n_t_r_o_l refers to the ability to selectively stop (_s_u_s_p_e_n_d) the ex- + ecution of processes and continue (_r_e_s_u_m_e) their execution at a later + point. A user typically employs this facility via an interactive in- + terface supplied jointly by the operating system kernel's terminal driver and bbaasshh. The shell associates a _j_o_b with each pipeline. It keeps a table of @@ -2861,8 +2912,8 @@ JJOOBB CCOONNTTRROOLL ically ^^ZZ, Control-Z) while a process is running causes that process to be stopped and returns control to bbaasshh. Typing the _d_e_l_a_y_e_d _s_u_s_p_e_n_d character (typically ^^YY, Control-Y) causes the process to be stopped - when it attempts to read input from the terminal, and control to be - returned to bbaasshh. The user may then manipulate the state of this job, + when it attempts to read input from the terminal, and control to be re- + turned to bbaasshh. The user may then manipulate the state of this job, using the bbgg command to continue it in the background, the ffgg command to continue it in the foreground, or the kkiillll command to kill it. A ^^ZZ takes effect immediately, and has the additional side effect of causing @@ -2872,18 +2923,18 @@ JJOOBB CCOONNTTRROOLL ter %% introduces a job specification (_j_o_b_s_p_e_c). Job number _n may be referred to as %%nn. A job may also be referred to using a prefix of the name used to start it, or using a substring that appears in its command - line. For example, %%ccee refers to a stopped ccee job. If a prefix - matches more than one job, bbaasshh reports an error. Using %%??ccee, on the - other hand, refers to any job containing the string ccee in its command - line. If the substring matches more than one job, bbaasshh reports an - error. The symbols %%%% and %%++ refer to the shell's notion of the _c_u_r_- - _r_e_n_t _j_o_b, which is the last job stopped while it was in the foreground - or started in the background. The _p_r_e_v_i_o_u_s _j_o_b may be referenced using - %%--. If there is only a single job, %%++ and %%-- can both be used to refer - to that job. In output pertaining to jobs (e.g., the output of the - jjoobbss command), the current job is always flagged with a ++, and the pre- - vious job with a --. A single % (with no accompanying job specifica- - tion) also refers to the current job. + line. For example, %%ccee refers to a stopped job whose command name be- + gins with ccee. If a prefix matches more than one job, bbaasshh reports an + error. Using %%??ccee, on the other hand, refers to any job containing the + string ccee in its command line. If the substring matches more than one + job, bbaasshh reports an error. The symbols %%%% and %%++ refer to the shell's + notion of the _c_u_r_r_e_n_t _j_o_b, which is the last job stopped while it was + in the foreground or started in the background. The _p_r_e_v_i_o_u_s _j_o_b may + be referenced using %%--. If there is only a single job, %%++ and %%-- can + both be used to refer to that job. In output pertaining to jobs (e.g., + the output of the jjoobbss command), the current job is always flagged with + a ++, and the previous job with a --. A single % (with no accompanying + job specification) also refers to the current job. Simply naming a job can be used to bring it into the foreground: %%11 is a synonym for ````ffgg %%11'''', bringing job 1 from the background into the @@ -2894,8 +2945,8 @@ JJOOBB CCOONNTTRROOLL bbaasshh waits until it is about to print a prompt before reporting changes in a job's status so as to not interrupt any other output. If the --bb option to the sseett builtin command is enabled, bbaasshh reports such changes - immediately. Any trap on SSIIGGCCHHLLDD is executed for each child that - exits. + immediately. Any trap on SSIIGGCCHHLLDD is executed for each child that ex- + its. If an attempt to exit bbaasshh is made while jobs are stopped (or, if the cchheecckkjjoobbss shell option has been enabled using the sshhoopptt builtin, run- @@ -2907,25 +2958,25 @@ JJOOBB CCOONNTTRROOLL When the shell is waiting for a job or process using the wwaaiitt builtin, and job control is enabled, wwaaiitt will return when the job changes - state. The --ff option will force wwaaiitt to wait until the job or process - terminates before returning. + state. The --ff option causes wwaaiitt to wait until the job or process ter- + minates before returning. PPRROOMMPPTTIINNGG When executing interactively, bbaasshh displays the primary prompt PPSS11 when it is ready to read a command, and the secondary prompt PPSS22 when it needs more input to complete a command. BBaasshh displays PPSS00 after it - reads a command but before executing it. BBaasshh displays PPSS44 as - described above before tracing each command when the --xx option is - enabled. BBaasshh allows these prompt strings to be customized by insert- - ing a number of backslash-escaped special characters that are decoded - as follows: + reads a command but before executing it. BBaasshh displays PPSS44 as de- + scribed above before tracing each command when the --xx option is en- + abled. BBaasshh allows these prompt strings to be customized by inserting + a number of backslash-escaped special characters that are decoded as + follows: \\aa an ASCII bell character (07) \\dd the date in "Weekday Month Date" format (e.g., "Tue May 26") \\DD{{_f_o_r_m_a_t}} - the _f_o_r_m_a_t is passed to _s_t_r_f_t_i_m_e(3) and the result is - inserted into the prompt string; an empty _f_o_r_m_a_t results - in a locale-specific time representation. The braces are + the _f_o_r_m_a_t is passed to _s_t_r_f_t_i_m_e(3) and the result is in- + serted into the prompt string; an empty _f_o_r_m_a_t results in + a locale-specific time representation. The braces are required \\ee an ASCII escape character (033) \\hh the hostname up to the first `.' @@ -2960,13 +3011,15 @@ PPRROOMMPPTTIINNGG The command number and the history number are usually different: the history number of a command is its position in the history list, which - may include commands restored from the history file (see HHIISSTTOORRYY - below), while the command number is the position in the sequence of - commands executed during the current shell session. After the string - is decoded, it is expanded via parameter expansion, command substitu- - tion, arithmetic expansion, and quote removal, subject to the value of - the pprroommppttvvaarrss shell option (see the description of the sshhoopptt command - under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). + may include commands restored from the history file (see HHIISSTTOORRYY be- + low), while the command number is the position in the sequence of com- + mands executed during the current shell session. After the string is + decoded, it is expanded via parameter expansion, command substitution, + arithmetic expansion, and quote removal, subject to the value of the + pprroommppttvvaarrss shell option (see the description of the sshhoopptt command under + SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). This can have unwanted side effects if + escaped portions of the string appear within command substitution or + contain characters special to word expansion. RREEAADDLLIINNEE This is the library that handles reading input when using an interac- @@ -3004,13 +3057,15 @@ RREEAADDLLIINNEE RReeaaddlliinnee IInniittiiaalliizzaattiioonn Readline is customized by putting commands in an initialization file (the _i_n_p_u_t_r_c file). The name of this file is taken from the value of - the IINNPPUUTTRRCC variable. If that variable is unset, the default is - _~_/_._i_n_p_u_t_r_c. When a program which uses the readline library starts up, - the initialization file is read, and the key bindings and variables are - set. There are only a few basic constructs allowed in the readline - initialization file. Blank lines are ignored. Lines beginning with a - ## are comments. Lines beginning with a $$ indicate conditional con- - structs. Other lines denote key bindings and variable settings. + the IINNPPUUTTRRCC variable. If that variable is unset, the default is _~_/_._i_n_- + _p_u_t_r_c. If that file does not exist or cannot be read, the ultimate + default is _/_e_t_c_/_i_n_p_u_t_r_c. When a program which uses the readline li- + brary starts up, the initialization file is read, and the key bindings + and variables are set. There are only a few basic constructs allowed + in the readline initialization file. Blank lines are ignored. Lines + beginning with a ## are comments. Lines beginning with a $$ indicate + conditional constructs. Other lines denote key bindings and variable + settings. The default key-bindings may be changed with an _i_n_p_u_t_r_c file. Other programs that use this library may add their own commands and bindings. @@ -3102,6 +3157,7 @@ RREEAADDLLIINNEE form sseett _v_a_r_i_a_b_l_e_-_n_a_m_e _v_a_l_u_e + or using the bbiinndd builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). Except where noted, readline variables can take the values OOnn or OOffff (without regard to case). Unrecognized variable names are ignored. @@ -3159,9 +3215,9 @@ RREEAADDLLIINNEE ber of possible completions generated by the ppoossssiibbllee--ccoommppllee-- ttiioonnss command. It may be set to any integer value greater than or equal to zero. If the number of possible completions is - greater than or equal to the value of this variable, the user is - asked whether or not he wishes to view them; otherwise they are - simply listed on the terminal. + greater than or equal to the value of this variable, readline + will ask whether or not the user wishes to view them; otherwise + they are simply listed on the terminal. ccoonnvveerrtt--mmeettaa ((OOnn)) If set to OOnn, readline will convert characters with the eighth bit set to an ASCII key sequence by stripping the eighth bit and @@ -3189,7 +3245,7 @@ RREEAADDLLIINNEE escapes to begin and end sequences of non-printing characters, which can be used to embed a terminal control sequence into the mode string. - eennaabbllee--bbrraacckkeetteedd--ppaassttee ((OOffff)) + eennaabbllee--bbrraacckkeetteedd--ppaassttee ((OOnn)) When set to OOnn, readline will configure the terminal in a way that will enable it to insert each paste into the editing buffer as a single string of characters, instead of treating each char- @@ -3198,15 +3254,15 @@ RREEAADDLLIINNEE mands. eennaabbllee--kkeeyyppaadd ((OOffff)) When set to OOnn, readline will try to enable the application key- - pad when it is called. Some systems need this to enable the - arrow keys. + pad when it is called. Some systems need this to enable the ar- + row keys. eennaabbllee--mmeettaa--kkeeyy ((OOnn)) When set to OOnn, readline will try to enable any meta modifier key the terminal claims to support when it is called. On many terminals, the meta key is used to send eight-bit characters. eexxppaanndd--ttiillddee ((OOffff)) - If set to OOnn, tilde expansion is performed when readline - attempts word completion. + If set to OOnn, tilde expansion is performed when readline at- + tempts word completion. hhiissttoorryy--pprreesseerrvvee--ppooiinntt ((OOffff)) If set to OOnn, the history code attempts to place point at the same location on each history line retrieved with pprreevviioouuss--hhiiss-- @@ -3224,165 +3280,166 @@ RREEAADDLLIINNEE When set to OOnn, makes readline use a single line for display, scrolling the input horizontally on a single screen line when it becomes longer than the screen width rather than wrapping to a - new line. + new line. This setting is automatically enabled for terminals + of height 1. iinnppuutt--mmeettaa ((OOffff)) - If set to OOnn, readline will enable eight-bit input (that is, it - will not strip the eighth bit from the characters it reads), - regardless of what the terminal claims it can support. The name - mmeettaa--ffllaagg is a synonym for this variable. The default is _O_f_f, - but readline will set it to _O_n if the locale contains eight-bit + If set to OOnn, readline will enable eight-bit input (that is, it + will not strip the eighth bit from the characters it reads), re- + gardless of what the terminal claims it can support. The name + mmeettaa--ffllaagg is a synonym for this variable. The default is _O_f_f, + but readline will set it to _O_n if the locale contains eight-bit characters. iisseeaarrcchh--tteerrmmiinnaattoorrss ((````CC--[[CC--JJ'''')) - The string of characters that should terminate an incremental - search without subsequently executing the character as a com- - mand. If this variable has not been given a value, the charac- + The string of characters that should terminate an incremental + search without subsequently executing the character as a com- + mand. If this variable has not been given a value, the charac- ters _E_S_C and _C_-_J will terminate an incremental search. kkeeyymmaapp ((eemmaaccss)) - Set the current readline keymap. The set of valid keymap names - is _e_m_a_c_s_, _e_m_a_c_s_-_s_t_a_n_d_a_r_d_, _e_m_a_c_s_-_m_e_t_a_, _e_m_a_c_s_-_c_t_l_x_, _v_i_, _v_i_-_c_o_m_- - _m_a_n_d, and _v_i_-_i_n_s_e_r_t. _v_i is equivalent to _v_i_-_c_o_m_m_a_n_d; _e_m_a_c_s is - equivalent to _e_m_a_c_s_-_s_t_a_n_d_a_r_d. The default value is _e_m_a_c_s; the + Set the current readline keymap. The set of valid keymap names + is _e_m_a_c_s_, _e_m_a_c_s_-_s_t_a_n_d_a_r_d_, _e_m_a_c_s_-_m_e_t_a_, _e_m_a_c_s_-_c_t_l_x_, _v_i_, _v_i_-_c_o_m_- + _m_a_n_d, and _v_i_-_i_n_s_e_r_t. _v_i is equivalent to _v_i_-_c_o_m_m_a_n_d; _e_m_a_c_s is + equivalent to _e_m_a_c_s_-_s_t_a_n_d_a_r_d. The default value is _e_m_a_c_s; the value of eeddiittiinngg--mmooddee also affects the default keymap. kkeeyysseeqq--ttiimmeeoouutt ((550000)) - Specifies the duration _r_e_a_d_l_i_n_e will wait for a character when - reading an ambiguous key sequence (one that can form a complete + Specifies the duration _r_e_a_d_l_i_n_e will wait for a character when + reading an ambiguous key sequence (one that can form a complete key sequence using the input read so far, or can take additional - input to complete a longer key sequence). If no input is - received within the timeout, _r_e_a_d_l_i_n_e will use the shorter but - complete key sequence. The value is specified in milliseconds, - so a value of 1000 means that _r_e_a_d_l_i_n_e will wait one second for - additional input. If this variable is set to a value less than - or equal to zero, or to a non-numeric value, _r_e_a_d_l_i_n_e will wait - until another key is pressed to decide which key sequence to + input to complete a longer key sequence). If no input is re- + ceived within the timeout, _r_e_a_d_l_i_n_e will use the shorter but + complete key sequence. The value is specified in milliseconds, + so a value of 1000 means that _r_e_a_d_l_i_n_e will wait one second for + additional input. If this variable is set to a value less than + or equal to zero, or to a non-numeric value, _r_e_a_d_l_i_n_e will wait + until another key is pressed to decide which key sequence to complete. mmaarrkk--ddiirreeccttoorriieess ((OOnn)) If set to OOnn, completed directory names have a slash appended. mmaarrkk--mmooddiiffiieedd--lliinneess ((OOffff)) - If set to OOnn, history lines that have been modified are dis- + If set to OOnn, history lines that have been modified are dis- played with a preceding asterisk (**). mmaarrkk--ssyymmlliinnkkeedd--ddiirreeccttoorriieess ((OOffff)) If set to OOnn, completed names which are symbolic links to direc- - tories have a slash appended (subject to the value of - mmaarrkk--ddiirreeccttoorriieess). + tories have a slash appended (subject to the value of mmaarrkk--ddii-- + rreeccttoorriieess). mmaattcchh--hhiiddddeenn--ffiilleess ((OOnn)) - This variable, when set to OOnn, causes readline to match files - whose names begin with a `.' (hidden files) when performing - filename completion. If set to OOffff, the leading `.' must be + This variable, when set to OOnn, causes readline to match files + whose names begin with a `.' (hidden files) when performing + filename completion. If set to OOffff, the leading `.' must be supplied by the user in the filename to be completed. mmeennuu--ccoommpplleettee--ddiissppllaayy--pprreeffiixx ((OOffff)) - If set to OOnn, menu completion displays the common prefix of the + If set to OOnn, menu completion displays the common prefix of the list of possible completions (which may be empty) before cycling through the list. oouuttppuutt--mmeettaa ((OOffff)) - If set to OOnn, readline will display characters with the eighth + If set to OOnn, readline will display characters with the eighth bit set directly rather than as a meta-prefixed escape sequence. The default is _O_f_f, but readline will set it to _O_n if the locale contains eight-bit characters. ppaaggee--ccoommpplleettiioonnss ((OOnn)) - If set to OOnn, readline uses an internal _m_o_r_e-like pager to dis- + If set to OOnn, readline uses an internal _m_o_r_e-like pager to dis- play a screenful of possible completions at a time. pprriinntt--ccoommpplleettiioonnss--hhoorriizzoonnttaallllyy ((OOffff)) - If set to OOnn, readline will display completions with matches - sorted horizontally in alphabetical order, rather than down the + If set to OOnn, readline will display completions with matches + sorted horizontally in alphabetical order, rather than down the screen. rreevveerrtt--aallll--aatt--nneewwlliinnee ((OOffff)) - If set to OOnn, readline will undo all changes to history lines + If set to OOnn, readline will undo all changes to history lines before returning when aacccceepptt--lliinnee is executed. By default, his- - tory lines may be modified and retain individual undo lists + tory lines may be modified and retain individual undo lists across calls to rreeaaddlliinnee. sshhooww--aallll--iiff--aammbbiigguuoouuss ((OOffff)) - This alters the default behavior of the completion functions. + This alters the default behavior of the completion functions. If set to OOnn, words which have more than one possible completion - cause the matches to be listed immediately instead of ringing + cause the matches to be listed immediately instead of ringing the bell. sshhooww--aallll--iiff--uunnmmooddiiffiieedd ((OOffff)) - This alters the default behavior of the completion functions in + This alters the default behavior of the completion functions in a fashion similar to sshhooww--aallll--iiff--aammbbiigguuoouuss. If set to OOnn, words - which have more than one possible completion without any possi- - ble partial completion (the possible completions don't share a - common prefix) cause the matches to be listed immediately - instead of ringing the bell. + which have more than one possible completion without any possi- + ble partial completion (the possible completions don't share a + common prefix) cause the matches to be listed immediately in- + stead of ringing the bell. sshhooww--mmooddee--iinn--pprroommpptt ((OOffff)) - If set to OOnn, add a string to the beginning of the prompt indi- - cating the editing mode: emacs, vi command, or vi insertion. + If set to OOnn, add a string to the beginning of the prompt indi- + cating the editing mode: emacs, vi command, or vi insertion. The mode strings are user-settable (e.g., _e_m_a_c_s_-_m_o_d_e_-_s_t_r_i_n_g). sskkiipp--ccoommpplleetteedd--tteexxtt ((OOffff)) - If set to OOnn, this alters the default completion behavior when - inserting a single match into the line. It's only active when - performing completion in the middle of a word. If enabled, - readline does not insert characters from the completion that - match characters after point in the word being completed, so + If set to OOnn, this alters the default completion behavior when + inserting a single match into the line. It's only active when + performing completion in the middle of a word. If enabled, + readline does not insert characters from the completion that + match characters after point in the word being completed, so portions of the word following the cursor are not duplicated. vvii--ccmmdd--mmooddee--ssttrriinngg ((((ccmmdd)))) - If the _s_h_o_w_-_m_o_d_e_-_i_n_-_p_r_o_m_p_t variable is enabled, this string is + If the _s_h_o_w_-_m_o_d_e_-_i_n_-_p_r_o_m_p_t variable is enabled, this string is displayed immediately before the last line of the primary prompt - when vi editing mode is active and in command mode. The value + when vi editing mode is active and in command mode. The value is expanded like a key binding, so the standard set of meta- and - control prefixes and backslash escape sequences is available. - Use the \1 and \2 escapes to begin and end sequences of non- - printing characters, which can be used to embed a terminal con- + control prefixes and backslash escape sequences is available. + Use the \1 and \2 escapes to begin and end sequences of non- + printing characters, which can be used to embed a terminal con- trol sequence into the mode string. vvii--iinnss--mmooddee--ssttrriinngg ((((iinnss)))) - If the _s_h_o_w_-_m_o_d_e_-_i_n_-_p_r_o_m_p_t variable is enabled, this string is + If the _s_h_o_w_-_m_o_d_e_-_i_n_-_p_r_o_m_p_t variable is enabled, this string is displayed immediately before the last line of the primary prompt when vi editing mode is active and in insertion mode. The value is expanded like a key binding, so the standard set of meta- and - control prefixes and backslash escape sequences is available. - Use the \1 and \2 escapes to begin and end sequences of non- - printing characters, which can be used to embed a terminal con- + control prefixes and backslash escape sequences is available. + Use the \1 and \2 escapes to begin and end sequences of non- + printing characters, which can be used to embed a terminal con- trol sequence into the mode string. vviissiibbllee--ssttaattss ((OOffff)) - If set to OOnn, a character denoting a file's type as reported by - _s_t_a_t(2) is appended to the filename when listing possible com- + If set to OOnn, a character denoting a file's type as reported by + _s_t_a_t(2) is appended to the filename when listing possible com- pletions. RReeaaddlliinnee CCoonnddiittiioonnaall CCoonnssttrruuccttss - Readline implements a facility similar in spirit to the conditional - compilation features of the C preprocessor which allows key bindings - and variable settings to be performed as the result of tests. There + Readline implements a facility similar in spirit to the conditional + compilation features of the C preprocessor which allows key bindings + and variable settings to be performed as the result of tests. There are four parser directives used. - $$iiff The $$iiff construct allows bindings to be made based on the edit- - ing mode, the terminal being used, or the application using + $$iiff The $$iiff construct allows bindings to be made based on the edit- + ing mode, the terminal being used, or the application using readline. The text of the test, after any comparison operator, - extends to the end of the line; unless otherwise noted, no + extends to the end of the line; unless otherwise noted, no characters are required to isolate it. - mmooddee The mmooddee== form of the $$iiff directive is used to test - whether readline is in emacs or vi mode. This may be - used in conjunction with the sseett kkeeyymmaapp command, for - instance, to set bindings in the _e_m_a_c_s_-_s_t_a_n_d_a_r_d and - _e_m_a_c_s_-_c_t_l_x keymaps only if readline is starting out in + mmooddee The mmooddee== form of the $$iiff directive is used to test + whether readline is in emacs or vi mode. This may be + used in conjunction with the sseett kkeeyymmaapp command, for in- + stance, to set bindings in the _e_m_a_c_s_-_s_t_a_n_d_a_r_d and + _e_m_a_c_s_-_c_t_l_x keymaps only if readline is starting out in emacs mode. - tteerrmm The tteerrmm== form may be used to include terminal-specific + tteerrmm The tteerrmm== form may be used to include terminal-specific key bindings, perhaps to bind the key sequences output by the terminal's function keys. The word on the right side of the == is tested against both the full name of the ter- - minal and the portion of the terminal name before the - first --. This allows _s_u_n to match both _s_u_n and _s_u_n_-_c_m_d, + minal and the portion of the terminal name before the + first --. This allows _s_u_n to match both _s_u_n and _s_u_n_-_c_m_d, for instance. vveerrssiioonn - The vveerrssiioonn test may be used to perform comparisons - against specific readline versions. The vveerrssiioonn expands - to the current readline version. The set of comparison - operators includes ==, (and ====), !!==, <<==, >>==, <<, and >>. - The version number supplied on the right side of the - operator consists of a major version number, an optional + The vveerrssiioonn test may be used to perform comparisons + against specific readline versions. The vveerrssiioonn expands + to the current readline version. The set of comparison + operators includes ==, (and ====), !!==, <<==, >>==, <<, and >>. + The version number supplied on the right side of the op- + erator consists of a major version number, an optional decimal point, and an optional minor version (e.g., 77..11). - If the minor version is omitted, it is assumed to be 00. + If the minor version is omitted, it is assumed to be 00. The operator may be separated from the string vveerrssiioonn and from the version number argument by whitespace. aapppplliiccaattiioonn The aapppplliiccaattiioonn construct is used to include application- - specific settings. Each program using the readline - library sets the _a_p_p_l_i_c_a_t_i_o_n _n_a_m_e, and an initialization + specific settings. Each program using the readline li- + brary sets the _a_p_p_l_i_c_a_t_i_o_n _n_a_m_e, and an initialization file can test for a particular value. This could be used - to bind key sequences to functions useful for a specific - program. For instance, the following command adds a key - sequence that quotes the current or previous word in + to bind key sequences to functions useful for a specific + program. For instance, the following command adds a key + sequence that quotes the current or previous word in bbaasshh: $$iiff Bash @@ -3392,12 +3449,12 @@ RREEAADDLLIINNEE _v_a_r_i_a_b_l_e The _v_a_r_i_a_b_l_e construct provides simple equality tests for - readline variables and values. The permitted comparison - operators are _=, _=_=, and _!_=. The variable name must be + readline variables and values. The permitted comparison + operators are _=, _=_=, and _!_=. The variable name must be separated from the comparison operator by whitespace; the - operator may be separated from the value on the right - hand side by whitespace. Both string and boolean vari- - ables may be tested. Boolean variables must be tested + operator may be separated from the value on the right + hand side by whitespace. Both string and boolean vari- + ables may be tested. Boolean variables must be tested against the values _o_n and _o_f_f. $$eennddiiff This command, as seen in the previous example, terminates an $$iiff @@ -3407,51 +3464,51 @@ RREEAADDLLIINNEE test fails. $$iinncclluuddee - This directive takes a single filename as an argument and reads - commands and bindings from that file. For example, the follow- + This directive takes a single filename as an argument and reads + commands and bindings from that file. For example, the follow- ing directive would read _/_e_t_c_/_i_n_p_u_t_r_c: $$iinncclluuddee _/_e_t_c_/_i_n_p_u_t_r_c SSeeaarrcchhiinngg - Readline provides commands for searching through the command history + Readline provides commands for searching through the command history (see HHIISSTTOORRYY below) for lines containing a specified string. There are two search modes: _i_n_c_r_e_m_e_n_t_a_l and _n_o_n_-_i_n_c_r_e_m_e_n_t_a_l. - Incremental searches begin before the user has finished typing the - search string. As each character of the search string is typed, read- + Incremental searches begin before the user has finished typing the + search string. As each character of the search string is typed, read- line displays the next entry from the history matching the string typed - so far. An incremental search requires only as many characters as - needed to find the desired history entry. The characters present in - the value of the iisseeaarrcchh--tteerrmmiinnaattoorrss variable are used to terminate an + so far. An incremental search requires only as many characters as + needed to find the desired history entry. The characters present in + the value of the iisseeaarrcchh--tteerrmmiinnaattoorrss variable are used to terminate an incremental search. If that variable has not been assigned a value the - Escape and Control-J characters will terminate an incremental search. - Control-G will abort an incremental search and restore the original - line. When the search is terminated, the history entry containing the + Escape and Control-J characters will terminate an incremental search. + Control-G will abort an incremental search and restore the original + line. When the search is terminated, the history entry containing the search string becomes the current line. - To find other matching entries in the history list, type Control-S or - Control-R as appropriate. This will search backward or forward in the - history for the next entry matching the search string typed so far. - Any other key sequence bound to a readline command will terminate the - search and execute that command. For instance, a _n_e_w_l_i_n_e will termi- + To find other matching entries in the history list, type Control-S or + Control-R as appropriate. This will search backward or forward in the + history for the next entry matching the search string typed so far. + Any other key sequence bound to a readline command will terminate the + search and execute that command. For instance, a _n_e_w_l_i_n_e will termi- nate the search and accept the line, thereby executing the command from the history list. Readline remembers the last incremental search string. If two Control- - Rs are typed without any intervening characters defining a new search + Rs are typed without any intervening characters defining a new search string, any remembered search string is used. - Non-incremental searches read the entire search string before starting - to search for matching history lines. The search string may be typed + Non-incremental searches read the entire search string before starting + to search for matching history lines. The search string may be typed by the user or be part of the contents of the current line. RReeaaddlliinnee CCoommmmaanndd NNaammeess - The following is a list of the names of the commands and the default + The following is a list of the names of the commands and the default key sequences to which they are bound. Command names without an accom- panying key sequence are unbound by default. In the following descrip- - tions, _p_o_i_n_t refers to the current cursor position, and _m_a_r_k refers to - a cursor position saved by the sseett--mmaarrkk command. The text between the + tions, _p_o_i_n_t refers to the current cursor position, and _m_a_r_k refers to + a cursor position saved by the sseett--mmaarrkk command. The text between the point and mark is referred to as the _r_e_g_i_o_n. CCoommmmaannddss ffoorr MMoovviinngg @@ -3467,100 +3524,104 @@ RREEAADDLLIINNEE Move forward to the end of the next word. Words are composed of alphanumeric characters (letters and digits). bbaacckkwwaarrdd--wwoorrdd ((MM--bb)) - Move back to the start of the current or previous word. Words + Move back to the start of the current or previous word. Words are composed of alphanumeric characters (letters and digits). sshheellll--ffoorrwwaarrdd--wwoorrdd - Move forward to the end of the next word. Words are delimited + Move forward to the end of the next word. Words are delimited by non-quoted shell metacharacters. sshheellll--bbaacckkwwaarrdd--wwoorrdd - Move back to the start of the current or previous word. Words + Move back to the start of the current or previous word. Words are delimited by non-quoted shell metacharacters. pprreevviioouuss--ssccrreeeenn--lliinnee - Attempt to move point to the same physical screen column on the - previous physical screen line. This will not have the desired - effect if the current Readline line does not take up more than - one physical line or if point is not greater than the length of + Attempt to move point to the same physical screen column on the + previous physical screen line. This will not have the desired + effect if the current Readline line does not take up more than + one physical line or if point is not greater than the length of the prompt plus the screen width. nneexxtt--ssccrreeeenn--lliinnee - Attempt to move point to the same physical screen column on the + Attempt to move point to the same physical screen column on the next physical screen line. This will not have the desired effect - if the current Readline line does not take up more than one - physical line or if the length of the current Readline line is + if the current Readline line does not take up more than one + physical line or if the length of the current Readline line is not greater than the length of the prompt plus the screen width. + cclleeaarr--ddiissppllaayy ((MM--CC--ll)) + Clear the screen and, if possible, the terminal's scrollback + buffer, then redraw the current line, leaving the current line + at the top of the screen. cclleeaarr--ssccrreeeenn ((CC--ll)) - Clear the screen leaving the current line at the top of the - screen. With an argument, refresh the current line without - clearing the screen. + Clear the screen, then redraw the current line, leaving the cur- + rent line at the top of the screen. With an argument, refresh + the current line without clearing the screen. rreeddrraaww--ccuurrrreenntt--lliinnee Refresh the current line. CCoommmmaannddss ffoorr MMaanniippuullaattiinngg tthhee HHiissttoorryy aacccceepptt--lliinnee ((NNeewwlliinnee,, RReettuurrnn)) Accept the line regardless of where the cursor is. If this line - is non-empty, add it to the history list according to the state - of the HHIISSTTCCOONNTTRROOLL variable. If the line is a modified history + is non-empty, add it to the history list according to the state + of the HHIISSTTCCOONNTTRROOLL variable. If the line is a modified history line, then restore the history line to its original state. pprreevviioouuss--hhiissttoorryy ((CC--pp)) Fetch the previous command from the history list, moving back in the list. nneexxtt--hhiissttoorryy ((CC--nn)) - Fetch the next command from the history list, moving forward in + Fetch the next command from the history list, moving forward in the list. bbeeggiinnnniinngg--ooff--hhiissttoorryy ((MM--<<)) Move to the first line in the history. eenndd--ooff--hhiissttoorryy ((MM-->>)) - Move to the end of the input history, i.e., the line currently + Move to the end of the input history, i.e., the line currently being entered. rreevveerrssee--sseeaarrcchh--hhiissttoorryy ((CC--rr)) - Search backward starting at the current line and moving `up' - through the history as necessary. This is an incremental + Search backward starting at the current line and moving `up' + through the history as necessary. This is an incremental search. ffoorrwwaarrdd--sseeaarrcchh--hhiissttoorryy ((CC--ss)) - Search forward starting at the current line and moving `down' - through the history as necessary. This is an incremental + Search forward starting at the current line and moving `down' + through the history as necessary. This is an incremental search. nnoonn--iinnccrreemmeennttaall--rreevveerrssee--sseeaarrcchh--hhiissttoorryy ((MM--pp)) Search backward through the history starting at the current line - using a non-incremental search for a string supplied by the + using a non-incremental search for a string supplied by the user. nnoonn--iinnccrreemmeennttaall--ffoorrwwaarrdd--sseeaarrcchh--hhiissttoorryy ((MM--nn)) - Search forward through the history using a non-incremental + Search forward through the history using a non-incremental search for a string supplied by the user. hhiissttoorryy--sseeaarrcchh--ffoorrwwaarrdd - Search forward through the history for the string of characters - between the start of the current line and the point. This is a + Search forward through the history for the string of characters + between the start of the current line and the point. This is a non-incremental search. hhiissttoorryy--sseeaarrcchh--bbaacckkwwaarrdd Search backward through the history for the string of characters - between the start of the current line and the point. This is a + between the start of the current line and the point. This is a non-incremental search. hhiissttoorryy--ssuubbssttrriinngg--sseeaarrcchh--bbaacckkwwaarrdd Search backward through the history for the string of characters - between the start of the current line and the current cursor - position (the _p_o_i_n_t). The search string may match anywhere in a + between the start of the current line and the current cursor po- + sition (the _p_o_i_n_t). The search string may match anywhere in a history line. This is a non-incremental search. hhiissttoorryy--ssuubbssttrriinngg--sseeaarrcchh--ffoorrwwaarrdd - Search forward through the history for the string of characters + Search forward through the history for the string of characters between the start of the current line and the point. The search - string may match anywhere in a history line. This is a non- - incremental search. + string may match anywhere in a history line. This is a non-in- + cremental search. yyaannkk--nntthh--aarrgg ((MM--CC--yy)) - Insert the first argument to the previous command (usually the + Insert the first argument to the previous command (usually the second word on the previous line) at point. With an argument _n, - insert the _nth word from the previous command (the words in the - previous command begin with word 0). A negative argument - inserts the _nth word from the end of the previous command. Once - the argument _n is computed, the argument is extracted as if the + insert the _nth word from the previous command (the words in the + previous command begin with word 0). A negative argument in- + serts the _nth word from the end of the previous command. Once + the argument _n is computed, the argument is extracted as if the "!_n" history expansion had been specified. yyaannkk--llaasstt--aarrgg ((MM--..,, MM--__)) - Insert the last argument to the previous command (the last word + Insert the last argument to the previous command (the last word of the previous history entry). With a numeric argument, behave - exactly like yyaannkk--nntthh--aarrgg. Successive calls to yyaannkk--llaasstt--aarrgg - move back through the history list, inserting the last word (or - the word specified by the argument to the first call) of each + exactly like yyaannkk--nntthh--aarrgg. Successive calls to yyaannkk--llaasstt--aarrgg + move back through the history list, inserting the last word (or + the word specified by the argument to the first call) of each line in turn. Any numeric argument supplied to these successive - calls determines the direction to move through the history. A - negative argument switches the direction through the history + calls determines the direction to move through the history. A + negative argument switches the direction through the history (back or forward). The history expansion facilities are used to extract the last word, as if the "!$" history expansion had been specified. @@ -3569,80 +3630,80 @@ RREEAADDLLIINNEE tory expansion as well as all of the shell word expansions. See HHIISSTTOORRYY EEXXPPAANNSSIIOONN below for a description of history expansion. hhiissttoorryy--eexxppaanndd--lliinnee ((MM--^^)) - Perform history expansion on the current line. See HHIISSTTOORRYY - EEXXPPAANNSSIIOONN below for a description of history expansion. + Perform history expansion on the current line. See HHIISSTTOORRYY EEXX-- + PPAANNSSIIOONN below for a description of history expansion. mmaaggiicc--ssppaaccee - Perform history expansion on the current line and insert a + Perform history expansion on the current line and insert a space. See HHIISSTTOORRYY EEXXPPAANNSSIIOONN below for a description of history expansion. aalliiaass--eexxppaanndd--lliinnee - Perform alias expansion on the current line. See AALLIIAASSEESS above + Perform alias expansion on the current line. See AALLIIAASSEESS above for a description of alias expansion. hhiissttoorryy--aanndd--aalliiaass--eexxppaanndd--lliinnee Perform history and alias expansion on the current line. iinnsseerrtt--llaasstt--aarrgguummeenntt ((MM--..,, MM--__)) A synonym for yyaannkk--llaasstt--aarrgg. ooppeerraattee--aanndd--ggeett--nneexxtt ((CC--oo)) - Accept the current line for execution and fetch the next line - relative to the current line from the history for editing. A - numeric argument, if supplied, specifies the history entry to + Accept the current line for execution and fetch the next line + relative to the current line from the history for editing. A + numeric argument, if supplied, specifies the history entry to use instead of the current line. eeddiitt--aanndd--eexxeeccuuttee--ccoommmmaanndd ((CC--xx CC--ee)) - Invoke an editor on the current command line, and execute the - result as shell commands. BBaasshh attempts to invoke $$VVIISSUUAALL, - $$EEDDIITTOORR, and _e_m_a_c_s as the editor, in that order. + Invoke an editor on the current command line, and execute the + result as shell commands. BBaasshh attempts to invoke $$VVIISSUUAALL, $$EEDD-- + IITTOORR, and _e_m_a_c_s as the editor, in that order. CCoommmmaannddss ffoorr CChhaannggiinngg TTeexxtt _e_n_d_-_o_f_-_f_i_l_e ((uussuuaallllyy CC--dd)) - The character indicating end-of-file as set, for example, by - ``stty''. If this character is read when there are no charac- - ters on the line, and point is at the beginning of the line, + The character indicating end-of-file as set, for example, by + ``stty''. If this character is read when there are no charac- + ters on the line, and point is at the beginning of the line, Readline interprets it as the end of input and returns EEOOFF. ddeelleettee--cchhaarr ((CC--dd)) Delete the character at point. If this function is bound to the same character as the tty EEOOFF character, as CC--dd commonly is, see above for the effects. bbaacckkwwaarrdd--ddeelleettee--cchhaarr ((RRuubboouutt)) - Delete the character behind the cursor. When given a numeric + Delete the character behind the cursor. When given a numeric argument, save the deleted text on the kill ring. ffoorrwwaarrdd--bbaacckkwwaarrdd--ddeelleettee--cchhaarr - Delete the character under the cursor, unless the cursor is at + Delete the character under the cursor, unless the cursor is at the end of the line, in which case the character behind the cur- sor is deleted. qquuootteedd--iinnsseerrtt ((CC--qq,, CC--vv)) - Add the next character typed to the line verbatim. This is how + Add the next character typed to the line verbatim. This is how to insert characters like CC--qq, for example. ttaabb--iinnsseerrtt ((CC--vv TTAABB)) Insert a tab character. sseellff--iinnsseerrtt ((aa,, bb,, AA,, 11,, !!,, ......)) Insert the character typed. ttrraannssppoossee--cchhaarrss ((CC--tt)) - Drag the character before point forward over the character at - point, moving point forward as well. If point is at the end of - the line, then this transposes the two characters before point. + Drag the character before point forward over the character at + point, moving point forward as well. If point is at the end of + the line, then this transposes the two characters before point. Negative arguments have no effect. ttrraannssppoossee--wwoorrddss ((MM--tt)) - Drag the word before point past the word after point, moving - point over that word as well. If point is at the end of the + Drag the word before point past the word after point, moving + point over that word as well. If point is at the end of the line, this transposes the last two words on the line. uuppccaassee--wwoorrdd ((MM--uu)) - Uppercase the current (or following) word. With a negative - argument, uppercase the previous word, but do not move point. + Uppercase the current (or following) word. With a negative ar- + gument, uppercase the previous word, but do not move point. ddoowwnnccaassee--wwoorrdd ((MM--ll)) - Lowercase the current (or following) word. With a negative - argument, lowercase the previous word, but do not move point. + Lowercase the current (or following) word. With a negative ar- + gument, lowercase the previous word, but do not move point. ccaappiittaalliizzee--wwoorrdd ((MM--cc)) - Capitalize the current (or following) word. With a negative - argument, capitalize the previous word, but do not move point. + Capitalize the current (or following) word. With a negative ar- + gument, capitalize the previous word, but do not move point. oovveerrwwrriittee--mmooddee - Toggle overwrite mode. With an explicit positive numeric argu- + Toggle overwrite mode. With an explicit positive numeric argu- ment, switches to overwrite mode. With an explicit non-positive numeric argument, switches to insert mode. This command affects - only eemmaaccss mode; vvii mode does overwrite differently. Each call + only eemmaaccss mode; vvii mode does overwrite differently. Each call to _r_e_a_d_l_i_n_e_(_) starts in insert mode. In overwrite mode, charac- - ters bound to sseellff--iinnsseerrtt replace the text at point rather than - pushing the text to the right. Characters bound to bbaacckk-- - wwaarrdd--ddeelleettee--cchhaarr replace the character before point with a + ters bound to sseellff--iinnsseerrtt replace the text at point rather than + pushing the text to the right. Characters bound to bbaacckk-- + wwaarrdd--ddeelleettee--cchhaarr replace the character before point with a space. By default, this command is unbound. KKiilllliinngg aanndd YYaannkkiinngg @@ -3651,31 +3712,31 @@ RREEAADDLLIINNEE bbaacckkwwaarrdd--kkiillll--lliinnee ((CC--xx RRuubboouutt)) Kill backward to the beginning of the line. uunniixx--lliinnee--ddiissccaarrdd ((CC--uu)) - Kill backward from point to the beginning of the line. The + Kill backward from point to the beginning of the line. The killed text is saved on the kill-ring. kkiillll--wwhhoollee--lliinnee - Kill all characters on the current line, no matter where point + Kill all characters on the current line, no matter where point is. kkiillll--wwoorrdd ((MM--dd)) - Kill from point to the end of the current word, or if between - words, to the end of the next word. Word boundaries are the + Kill from point to the end of the current word, or if between + words, to the end of the next word. Word boundaries are the same as those used by ffoorrwwaarrdd--wwoorrdd. bbaacckkwwaarrdd--kkiillll--wwoorrdd ((MM--RRuubboouutt)) - Kill the word behind point. Word boundaries are the same as + Kill the word behind point. Word boundaries are the same as those used by bbaacckkwwaarrdd--wwoorrdd. sshheellll--kkiillll--wwoorrdd - Kill from point to the end of the current word, or if between - words, to the end of the next word. Word boundaries are the + Kill from point to the end of the current word, or if between + words, to the end of the next word. Word boundaries are the same as those used by sshheellll--ffoorrwwaarrdd--wwoorrdd. sshheellll--bbaacckkwwaarrdd--kkiillll--wwoorrdd - Kill the word behind point. Word boundaries are the same as + Kill the word behind point. Word boundaries are the same as those used by sshheellll--bbaacckkwwaarrdd--wwoorrdd. uunniixx--wwoorrdd--rruubboouutt ((CC--ww)) - Kill the word behind point, using white space as a word bound- + Kill the word behind point, using white space as a word bound- ary. The killed text is saved on the kill-ring. uunniixx--ffiilleennaammee--rruubboouutt - Kill the word behind point, using white space and the slash - character as the word boundaries. The killed text is saved on + Kill the word behind point, using white space and the slash + character as the word boundaries. The killed text is saved on the kill-ring. ddeelleettee--hhoorriizzoonnttaall--ssppaaccee ((MM--\\)) Delete all spaces and tabs around point. @@ -3684,58 +3745,57 @@ RREEAADDLLIINNEE ccooppyy--rreeggiioonn--aass--kkiillll Copy the text in the region to the kill buffer. ccooppyy--bbaacckkwwaarrdd--wwoorrdd - Copy the word before point to the kill buffer. The word bound- + Copy the word before point to the kill buffer. The word bound- aries are the same as bbaacckkwwaarrdd--wwoorrdd. ccooppyy--ffoorrwwaarrdd--wwoorrdd - Copy the word following point to the kill buffer. The word + Copy the word following point to the kill buffer. The word boundaries are the same as ffoorrwwaarrdd--wwoorrdd. yyaannkk ((CC--yy)) Yank the top of the kill ring into the buffer at point. yyaannkk--ppoopp ((MM--yy)) - Rotate the kill ring, and yank the new top. Only works follow- + Rotate the kill ring, and yank the new top. Only works follow- ing yyaannkk or yyaannkk--ppoopp. NNuummeerriicc AArrgguummeennttss ddiiggiitt--aarrgguummeenntt ((MM--00,, MM--11,, ......,, MM----)) - Add this digit to the argument already accumulating, or start a + Add this digit to the argument already accumulating, or start a new argument. M-- starts a negative argument. uunniivveerrssaall--aarrgguummeenntt - This is another way to specify an argument. If this command is - followed by one or more digits, optionally with a leading minus - sign, those digits define the argument. If the command is fol- - lowed by digits, executing uunniivveerrssaall--aarrgguummeenntt again ends the - numeric argument, but is otherwise ignored. As a special case, - if this command is immediately followed by a character that is - neither a digit nor minus sign, the argument count for the next - command is multiplied by four. The argument count is initially - one, so executing this function the first time makes the argu- + This is another way to specify an argument. If this command is + followed by one or more digits, optionally with a leading minus + sign, those digits define the argument. If the command is fol- + lowed by digits, executing uunniivveerrssaall--aarrgguummeenntt again ends the nu- + meric argument, but is otherwise ignored. As a special case, if + this command is immediately followed by a character that is nei- + ther a digit nor minus sign, the argument count for the next + command is multiplied by four. The argument count is initially + one, so executing this function the first time makes the argu- ment count four, a second time makes the argument count sixteen, and so on. CCoommpplleettiinngg ccoommpplleettee ((TTAABB)) - Attempt to perform completion on the text before point. BBaasshh + Attempt to perform completion on the text before point. BBaasshh attempts completion treating the text as a variable (if the text - begins with $$), username (if the text begins with ~~), hostname - (if the text begins with @@), or command (including aliases and + begins with $$), username (if the text begins with ~~), hostname + (if the text begins with @@), or command (including aliases and functions) in turn. If none of these produces a match, filename completion is attempted. ppoossssiibbllee--ccoommpplleettiioonnss ((MM--??)) List the possible completions of the text before point. iinnsseerrtt--ccoommpplleettiioonnss ((MM--**)) - Insert all completions of the text before point that would have + Insert all completions of the text before point that would have been generated by ppoossssiibbllee--ccoommpplleettiioonnss. mmeennuu--ccoommpplleettee - Similar to ccoommpplleettee, but replaces the word to be completed with - a single match from the list of possible completions. Repeated - execution of mmeennuu--ccoommpplleettee steps through the list of possible - completions, inserting each match in turn. At the end of the + Similar to ccoommpplleettee, but replaces the word to be completed with + a single match from the list of possible completions. Repeated + execution of mmeennuu--ccoommpplleettee steps through the list of possible + completions, inserting each match in turn. At the end of the list of completions, the bell is rung (subject to the setting of bbeellll--ssttyyllee) and the original text is restored. An argument of _n - moves _n positions forward in the list of matches; a negative - argument may be used to move backward through the list. This - command is intended to be bound to TTAABB, but is unbound by - default. + moves _n positions forward in the list of matches; a negative ar- + gument may be used to move backward through the list. This com- + mand is intended to be bound to TTAABB, but is unbound by default. mmeennuu--ccoommpplleettee--bbaacckkwwaarrdd Identical to mmeennuu--ccoommpplleettee, but moves backward through the list of possible completions, as if mmeennuu--ccoommpplleettee had been given a @@ -3857,18 +3917,18 @@ RREEAADDLLIINNEE ning of the line. In either case, the line is accepted as if a newline had been typed. The default value of ccoommmmeenntt--bbeeggiinn causes this command to make the current line a shell comment. - If a numeric argument causes the comment character to be - removed, the line will be executed by the shell. + If a numeric argument causes the comment character to be re- + moved, the line will be executed by the shell. gglloobb--ccoommpplleettee--wwoorrdd ((MM--gg)) - The word before point is treated as a pattern for pathname - expansion, with an asterisk implicitly appended. This pattern - is used to generate a list of matching filenames for possible - completions. + The word before point is treated as a pattern for pathname ex- + pansion, with an asterisk implicitly appended. This pattern is + used to generate a list of matching filenames for possible com- + pletions. gglloobb--eexxppaanndd--wwoorrdd ((CC--xx **)) - The word before point is treated as a pattern for pathname - expansion, and the list of matching filenames is inserted, - replacing the word. If a numeric argument is supplied, an - asterisk is appended before pathname expansion. + The word before point is treated as a pattern for pathname ex- + pansion, and the list of matching filenames is inserted, replac- + ing the word. If a numeric argument is supplied, an asterisk is + appended before pathname expansion. gglloobb--lliisstt--eexxppaannssiioonnss ((CC--xx gg)) The list of expansions that would have been generated by gglloobb--eexxppaanndd--wwoorrdd is displayed, and the line is redrawn. If a @@ -3921,8 +3981,8 @@ RREEAADDLLIINNEE --ff or --dd option is used for filename or directory name completion, the shell variable FFIIGGNNOORREE is used to filter the matches. - Any completions specified by a pathname expansion pattern to the --GG - option are generated next. The words generated by the pattern need not + Any completions specified by a pathname expansion pattern to the --GG op- + tion are generated next. The words generated by the pattern need not match the word being completed. The GGLLOOBBIIGGNNOORREE shell variable is not used to filter the matches, but the FFIIGGNNOORREE variable is used. @@ -3942,8 +4002,8 @@ RREEAADDLLIINNEE variables are assigned values as described above under SShheellll VVaarriiaabblleess. If a shell function is being invoked, the CCOOMMPP__WWOORRDDSS and CCOOMMPP__CCWWOORRDD variables are also set. When the function or command is invoked, the - first argument ($$11) is the name of the command whose arguments are - being completed, the second argument ($$22) is the word being completed, + first argument ($$11) is the name of the command whose arguments are be- + ing completed, the second argument ($$22) is the word being completed, and the third argument ($$33) is the word preceding the word being com- pleted on the current command line. No filtering of the generated com- pletions against the word being completed is performed; the function or @@ -3975,8 +4035,8 @@ RREEAADDLLIINNEE to the readline completion code as the list of possible completions. If the previously-applied actions do not generate any matches, and the - --oo ddiirrnnaammeess option was supplied to ccoommpplleettee when the compspec was - defined, directory name completion is attempted. + --oo ddiirrnnaammeess option was supplied to ccoommpplleettee when the compspec was de- + fined, directory name completion is attempted. If the --oo pplluussddiirrss option was supplied to ccoommpplleettee when the compspec was defined, directory name completion is attempted and any matches are @@ -4011,8 +4071,8 @@ RREEAADDLLIINNEE than being loaded all at once. For instance, assuming that there is a library of compspecs, each kept - in a file corresponding to the name of the command, the following - default completion function would load completions dynamically: + in a file corresponding to the name of the command, the following de- + fault completion function would load completions dynamically: _completion_loader() { @@ -4045,20 +4105,20 @@ HHIISSTTOORRYY history list to $$HHIISSTTFFIILLEE. If the hhiissttaappppeenndd shell option is enabled (see the description of sshhoopptt under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below), the lines are appended to the history file, otherwise the history file is - overwritten. If HHIISSTTFFIILLEE is unset, or if the history file is - unwritable, the history is not saved. If the HHIISSTTTTIIMMEEFFOORRMMAATT variable - is set, time stamps are written to the history file, marked with the - history comment character, so they may be preserved across shell ses- - sions. This uses the history comment character to distinguish time- - stamps from other history lines. After saving the history, the history - file is truncated to contain no more than HHIISSTTFFIILLEESSIIZZEE lines. If HHIISSTT-- - FFIILLEESSIIZZEE is unset, or set to null, a non-numeric value, or a numeric - value less than zero, the history file is not truncated. + overwritten. If HHIISSTTFFIILLEE is unset, or if the history file is un- + writable, the history is not saved. If the HHIISSTTTTIIMMEEFFOORRMMAATT variable is + set, time stamps are written to the history file, marked with the his- + tory comment character, so they may be preserved across shell sessions. + This uses the history comment character to distinguish timestamps from + other history lines. After saving the history, the history file is + truncated to contain no more than HHIISSTTFFIILLEESSIIZZEE lines. If HHIISSTTFFIILLEESSIIZZEE + is unset, or set to null, a non-numeric value, or a numeric value less + than zero, the history file is not truncated. The builtin command ffcc (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below) may be used to list or edit and re-execute a portion of the history list. The hhiiss-- - ttoorryy builtin may be used to display or modify the history list and - manipulate the history file. When using command-line editing, search + ttoorryy builtin may be used to display or modify the history list and ma- + nipulate the history file. When using command-line editing, search commands are available in each editing mode that provide access to the history list. @@ -4070,8 +4130,8 @@ HHIISSTTOORRYY necessary to preserve syntactic correctness. The lliitthhiisstt shell option causes the shell to save the command with embedded newlines instead of semicolons. See the description of the sshhoopptt builtin below under SSHHEELLLL - BBUUIILLTTIINN CCOOMMMMAANNDDSS for information on setting and unsetting shell - options. + BBUUIILLTTIINN CCOOMMMMAANNDDSS for information on setting and unsetting shell op- + tions. HHIISSTTOORRYY EEXXPPAANNSSIIOONN The shell supports a history expansion feature that is similar to the @@ -4088,8 +4148,8 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN History expansion is performed immediately after a complete line is read, before the shell breaks it into words, and is performed on each - line individually without taking quoting on previous lines into - account. It takes place in two parts. The first is to determine which + line individually without taking quoting on previous lines into ac- + count. It takes place in two parts. The first is to determine which line from the history list to use during substitution. The second is to select portions of that line for inclusion into the current one. The line selected from the history is the _e_v_e_n_t, and the portions of @@ -4099,9 +4159,9 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN _t_e_r-separated words surrounded by quotes are considered one word. His- tory expansions are introduced by the appearance of the history expan- sion character, which is !! by default. Only backslash (\\) and single - quotes can quote the history expansion character, but the history - expansion character is also treated as quoted if it immediately pre- - cedes the closing double quote in a double-quoted string. + quotes can quote the history expansion character, but the history ex- + pansion character is also treated as quoted if it immediately precedes + the closing double quote in a double-quoted string. Several characters inhibit history expansion if found immediately fol- lowing the history expansion character, even if it is unquoted: space, @@ -4109,8 +4169,8 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN enabled, (( will also inhibit expansion. Several shell options settable with the sshhoopptt builtin may be used to - tailor the behavior of history expansion. If the hhiissttvveerriiffyy shell - option is enabled (see the description of the sshhoopptt builtin below), and + tailor the behavior of history expansion. If the hhiissttvveerriiffyy shell op- + tion is enabled (see the description of the sshhoopptt builtin below), and rreeaaddlliinnee is being used, history substitutions are not immediately passed to the shell parser. Instead, the expanded line is reloaded into the rreeaaddlliinnee editing buffer for further modification. If rreeaaddlliinnee @@ -4144,10 +4204,12 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN !!??_s_t_r_i_n_g[[??]] Refer to the most recent command preceding the current position in the history list containing _s_t_r_i_n_g. The trailing ?? may be - omitted if _s_t_r_i_n_g is followed immediately by a newline. + omitted if _s_t_r_i_n_g is followed immediately by a newline. If + _s_t_r_i_n_g is missing, the string from the most recent search is + used; it is an error if there is no previous search string. ^^_s_t_r_i_n_g_1^^_s_t_r_i_n_g_2^^ Quick substitution. Repeat the previous command, replacing - _s_t_r_i_n_g_1 with _s_t_r_i_n_g_2. Equivalent to ``!!:s/_s_t_r_i_n_g_1/_s_t_r_i_n_g_2/'' + _s_t_r_i_n_g_1 with _s_t_r_i_n_g_2. Equivalent to ``!!:s^_s_t_r_i_n_g_1^_s_t_r_i_n_g_2^'' (see MMooddiiffiieerrss below). !!## The entire command line typed so far. @@ -4163,22 +4225,26 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN The zeroth word. For the shell, this is the command word. _n The _nth word. ^^ The first argument. That is, word 1. - $$ The last word. This is usually the last argument, but will - expand to the zeroth word if there is only one word in the line. - %% The word matched by the most recent `?_s_t_r_i_n_g?' search. + $$ The last word. This is usually the last argument, but will ex- + pand to the zeroth word if there is only one word in the line. + %% The first word matched by the most recent `?_s_t_r_i_n_g?' search, if + the search string begins with a character that is part of a + word. _x--_y A range of words; `-_y' abbreviates `0-_y'. ** All of the words but the zeroth. This is a synonym for `_1_-_$'. It is not an error to use ** if there is just one word in the event; the empty string is returned in that case. xx** Abbreviates _x_-_$. - xx-- Abbreviates _x_-_$ like xx**, but omits the last word. + xx-- Abbreviates _x_-_$ like xx**, but omits the last word. If xx is miss- + ing, it defaults to 0. - If a word designator is supplied without an event specification, the + If a word designator is supplied without an event specification, the previous command is used as the event. MMooddiiffiieerrss - After the optional word designator, there may appear a sequence of one - or more of the following modifiers, each preceded by a `:'. + After the optional word designator, there may appear a sequence of one + or more of the following modifiers, each preceded by a `:'. These mod- + ify, or edit, the word or words selected from the history event. hh Remove a trailing filename component, leaving only the head. tt Remove all leading filename components, leaving the tail. @@ -4187,24 +4253,26 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN pp Print the new command but do not execute it. qq Quote the substituted words, escaping further substitutions. xx Quote the substituted words as with qq, but break into words at - bbllaannkkss and newlines. + bbllaannkkss and newlines. The qq and xx modifiers are mutually exclu- + sive; the last one supplied is used. ss//_o_l_d//_n_e_w// - Substitute _n_e_w for the first occurrence of _o_l_d in the event - line. Any delimiter can be used in place of /. The final - delimiter is optional if it is the last character of the event - line. The delimiter may be quoted in _o_l_d and _n_e_w with a single - backslash. If & appears in _n_e_w, it is replaced by _o_l_d. A sin- - gle backslash will quote the &. If _o_l_d is null, it is set to - the last _o_l_d substituted, or, if no previous history substitu- - tions took place, the last _s_t_r_i_n_g in a !!??_s_t_r_i_n_g[[??]] search. + Substitute _n_e_w for the first occurrence of _o_l_d in the event + line. Any character may be used as the delimiter in place of /. + The final delimiter is optional if it is the last character of + the event line. The delimiter may be quoted in _o_l_d and _n_e_w with + a single backslash. If & appears in _n_e_w, it is replaced by _o_l_d. + A single backslash will quote the &. If _o_l_d is null, it is set + to the last _o_l_d substituted, or, if no previous history substi- + tutions took place, the last _s_t_r_i_n_g in a !!??_s_t_r_i_n_g[[??]] search. + If _n_e_w is null, each matching _o_l_d is deleted. && Repeat the previous substitution. gg Cause changes to be applied over the entire event line. This is used in conjunction with `::ss' (e.g., `::ggss//_o_l_d//_n_e_w//') or `::&&'. If used with `::ss', any delimiter can be used in place of /, and the final delimiter is optional if it is the last character of the event line. An aa may be used as a synonym for gg. - GG Apply the following `ss' modifier once to each word in the event - line. + GG Apply the following `ss' or `&&' modifier once to each word in the + event line. SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS Unless otherwise noted, each builtin command documented in this section @@ -4223,8 +4291,8 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS .. _f_i_l_e_n_a_m_e [_a_r_g_u_m_e_n_t_s] ssoouurrccee _f_i_l_e_n_a_m_e [_a_r_g_u_m_e_n_t_s] - Read and execute commands from _f_i_l_e_n_a_m_e in the current shell - environment and return the exit status of the last command exe- + Read and execute commands from _f_i_l_e_n_a_m_e in the current shell en- + vironment and return the exit status of the last command exe- cuted from _f_i_l_e_n_a_m_e. If _f_i_l_e_n_a_m_e does not contain a slash, filenames in PPAATTHH are used to find the directory containing _f_i_l_e_n_a_m_e. The file searched for in PPAATTHH need not be executable. @@ -4232,15 +4300,15 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS searched if no file is found in PPAATTHH. If the ssoouurrcceeppaatthh option to the sshhoopptt builtin command is turned off, the PPAATTHH is not searched. If any _a_r_g_u_m_e_n_t_s are supplied, they become the posi- - tional parameters when _f_i_l_e_n_a_m_e is executed. Otherwise the - positional parameters are unchanged. If the --TT option is - enabled, ssoouurrccee inherits any trap on DDEEBBUUGG; if it is not, any - DDEEBBUUGG trap string is saved and restored around the call to - ssoouurrccee, and ssoouurrccee unsets the DDEEBBUUGG trap while it executes. If - --TT is not set, and the sourced file changes the DDEEBBUUGG trap, the - new value is retained when ssoouurrccee completes. The return status - is the status of the last command exited within the script (0 if - no commands are executed), and false if _f_i_l_e_n_a_m_e is not found or + tional parameters when _f_i_l_e_n_a_m_e is executed. Otherwise the po- + sitional parameters are unchanged. If the --TT option is enabled, + ssoouurrccee inherits any trap on DDEEBBUUGG; if it is not, any DDEEBBUUGG trap + string is saved and restored around the call to ssoouurrccee, and + ssoouurrccee unsets the DDEEBBUUGG trap while it executes. If --TT is not + set, and the sourced file changes the DDEEBBUUGG trap, the new value + is retained when ssoouurrccee completes. The return status is the + status of the last command exited within the script (0 if no + commands are executed), and false if _f_i_l_e_n_a_m_e is not found or cannot be read. aalliiaass [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] @@ -4250,8 +4318,8 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS _v_a_l_u_e is given. A trailing space in _v_a_l_u_e causes the next word to be checked for alias substitution when the alias is expanded. For each _n_a_m_e in the argument list for which no _v_a_l_u_e is sup- - plied, the name and value of the alias is printed. AAlliiaass - returns true unless a _n_a_m_e is given for which no alias has been + plied, the name and value of the alias is printed. AAlliiaass re- + turns true unless a _n_a_m_e is given for which no alias has been defined. bbgg [_j_o_b_s_p_e_c ...] @@ -4270,10 +4338,10 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS bbiinndd [--mm _k_e_y_m_a_p] _k_e_y_s_e_q:_r_e_a_d_l_i_n_e_-_c_o_m_m_a_n_d Display current rreeaaddlliinnee key and function bindings, bind a key sequence to a rreeaaddlliinnee function or macro, or set a rreeaaddlliinnee - variable. Each non-option argument is a command as it would - appear in _._i_n_p_u_t_r_c, but each binding or command must be passed - as a separate argument; e.g., '"\C-x\C-r": re-read-init-file'. - Options, if supplied, have the following meanings: + variable. Each non-option argument is a command as it would ap- + pear in _._i_n_p_u_t_r_c, but each binding or command must be passed as + a separate argument; e.g., '"\C-x\C-r": re-read-init-file'. Op- + tions, if supplied, have the following meanings: --mm _k_e_y_m_a_p Use _k_e_y_m_a_p as the keymap to be affected by the subsequent bindings. Acceptable _k_e_y_m_a_p names are _e_m_a_c_s_, _e_m_a_c_s_-_s_t_a_n_- @@ -4302,112 +4370,114 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --rr _k_e_y_s_e_q Remove any current binding for _k_e_y_s_e_q. --xx _k_e_y_s_e_q::_s_h_e_l_l_-_c_o_m_m_a_n_d - Cause _s_h_e_l_l_-_c_o_m_m_a_n_d to be executed whenever _k_e_y_s_e_q is - entered. When _s_h_e_l_l_-_c_o_m_m_a_n_d is executed, the shell sets + Cause _s_h_e_l_l_-_c_o_m_m_a_n_d to be executed whenever _k_e_y_s_e_q is en- + tered. When _s_h_e_l_l_-_c_o_m_m_a_n_d is executed, the shell sets the RREEAADDLLIINNEE__LLIINNEE variable to the contents of the rreeaadd-- - lliinnee line buffer and the RREEAADDLLIINNEE__PPOOIINNTT variable to the - current location of the insertion point. If the executed - command changes the value of RREEAADDLLIINNEE__LLIINNEE or RREEAADD-- - LLIINNEE__PPOOIINNTT, those new values will be reflected in the - editing state. - --XX List all key sequences bound to shell commands and the - associated commands in a format that can be reused as - input. - - The return value is 0 unless an unrecognized option is given or + lliinnee line buffer and the RREEAADDLLIINNEE__PPOOIINNTT and RREEAADDLLIINNEE__MMAARRKK + variables to the current location of the insertion point + and the saved insertion point (the mark), respectively. + If the executed command changes the value of any of RREEAADD-- + LLIINNEE__LLIINNEE, RREEAADDLLIINNEE__PPOOIINNTT, or RREEAADDLLIINNEE__MMAARRKK, those new + values will be reflected in the editing state. + --XX List all key sequences bound to shell commands and the + associated commands in a format that can be reused as in- + put. + + The return value is 0 unless an unrecognized option is given or an error occurred. bbrreeaakk [_n] - Exit from within a ffoorr, wwhhiillee, uunnttiill, or sseelleecctt loop. If _n is - specified, break _n levels. _n must be >= 1. If _n is greater - than the number of enclosing loops, all enclosing loops are - exited. The return value is 0 unless _n is not greater than or + Exit from within a ffoorr, wwhhiillee, uunnttiill, or sseelleecctt loop. If _n is + specified, break _n levels. _n must be >= 1. If _n is greater + than the number of enclosing loops, all enclosing loops are ex- + ited. The return value is 0 unless _n is not greater than or equal to 1. bbuuiillttiinn _s_h_e_l_l_-_b_u_i_l_t_i_n [_a_r_g_u_m_e_n_t_s] - Execute the specified shell builtin, passing it _a_r_g_u_m_e_n_t_s, and + Execute the specified shell builtin, passing it _a_r_g_u_m_e_n_t_s, and return its exit status. This is useful when defining a function - whose name is the same as a shell builtin, retaining the func- + whose name is the same as a shell builtin, retaining the func- tionality of the builtin within the function. The ccdd builtin is - commonly redefined this way. The return status is false if + commonly redefined this way. The return status is false if _s_h_e_l_l_-_b_u_i_l_t_i_n is not a shell builtin command. ccaalllleerr [_e_x_p_r] Returns the context of any active subroutine call (a shell func- tion or a script executed with the .. or ssoouurrccee builtins). With- out _e_x_p_r, ccaalllleerr displays the line number and source filename of - the current subroutine call. If a non-negative integer is sup- + the current subroutine call. If a non-negative integer is sup- plied as _e_x_p_r, ccaalllleerr displays the line number, subroutine name, - and source file corresponding to that position in the current - execution call stack. This extra information may be used, for - example, to print a stack trace. The current frame is frame 0. - The return value is 0 unless the shell is not executing a sub- - routine call or _e_x_p_r does not correspond to a valid position in + and source file corresponding to that position in the current + execution call stack. This extra information may be used, for + example, to print a stack trace. The current frame is frame 0. + The return value is 0 unless the shell is not executing a sub- + routine call or _e_x_p_r does not correspond to a valid position in the call stack. ccdd [--LL|[--PP [--ee]] [-@]] [_d_i_r] - Change the current directory to _d_i_r. if _d_i_r is not supplied, - the value of the HHOOMMEE shell variable is the default. Any addi- + Change the current directory to _d_i_r. if _d_i_r is not supplied, + the value of the HHOOMMEE shell variable is the default. Any addi- tional arguments following _d_i_r are ignored. The variable CCDDPPAATTHH - defines the search path for the directory containing _d_i_r: each - directory name in CCDDPPAATTHH is searched for _d_i_r. Alternative - directory names in CCDDPPAATTHH are separated by a colon (:). A null - directory name in CCDDPPAATTHH is the same as the current directory, + defines the search path for the directory containing _d_i_r: each + directory name in CCDDPPAATTHH is searched for _d_i_r. Alternative di- + rectory names in CCDDPPAATTHH are separated by a colon (:). A null + directory name in CCDDPPAATTHH is the same as the current directory, i.e., ``..''. If _d_i_r begins with a slash (/), then CCDDPPAATTHH is not - used. The --PP option causes ccdd to use the physical directory - structure by resolving symbolic links while traversing _d_i_r and + used. The --PP option causes ccdd to use the physical directory + structure by resolving symbolic links while traversing _d_i_r and before processing instances of _._. in _d_i_r (see also the --PP option to the sseett builtin command); the --LL option forces symbolic links - to be followed by resolving the link after processing instances + to be followed by resolving the link after processing instances of _._. in _d_i_r. If _._. appears in _d_i_r, it is processed by removing - the immediately previous pathname component from _d_i_r, back to a - slash or the beginning of _d_i_r. If the --ee option is supplied - with --PP, and the current working directory cannot be success- - fully determined after a successful directory change, ccdd will - return an unsuccessful status. On systems that support it, the - --@@ option presents the extended attributes associated with a - file as a directory. An argument of -- is converted to $$OOLLDDPPWWDD + the immediately previous pathname component from _d_i_r, back to a + slash or the beginning of _d_i_r. If the --ee option is supplied + with --PP, and the current working directory cannot be success- + fully determined after a successful directory change, ccdd will + return an unsuccessful status. On systems that support it, the + --@@ option presents the extended attributes associated with a + file as a directory. An argument of -- is converted to $$OOLLDDPPWWDD before the directory change is attempted. If a non-empty direc- - tory name from CCDDPPAATTHH is used, or if -- is the first argument, + tory name from CCDDPPAATTHH is used, or if -- is the first argument, and the directory change is successful, the absolute pathname of - the new working directory is written to the standard output. - The return value is true if the directory was successfully + the new working directory is written to the standard output. + The return value is true if the directory was successfully changed; false otherwise. ccoommmmaanndd [--ppVVvv] _c_o_m_m_a_n_d [_a_r_g ...] - Run _c_o_m_m_a_n_d with _a_r_g_s suppressing the normal shell function + Run _c_o_m_m_a_n_d with _a_r_g_s suppressing the normal shell function lookup. Only builtin commands or commands found in the PPAATTHH are - executed. If the --pp option is given, the search for _c_o_m_m_a_n_d is - performed using a default value for PPAATTHH that is guaranteed to - find all of the standard utilities. If either the --VV or --vv - option is supplied, a description of _c_o_m_m_a_n_d is printed. The --vv - option causes a single word indicating the command or filename + executed. If the --pp option is given, the search for _c_o_m_m_a_n_d is + performed using a default value for PPAATTHH that is guaranteed to + find all of the standard utilities. If either the --VV or --vv op- + tion is supplied, a description of _c_o_m_m_a_n_d is printed. The --vv + option causes a single word indicating the command or filename used to invoke _c_o_m_m_a_n_d to be displayed; the --VV option produces a - more verbose description. If the --VV or --vv option is supplied, - the exit status is 0 if _c_o_m_m_a_n_d was found, and 1 if not. If + more verbose description. If the --VV or --vv option is supplied, + the exit status is 0 if _c_o_m_m_a_n_d was found, and 1 if not. If neither option is supplied and an error occurred or _c_o_m_m_a_n_d can- - not be found, the exit status is 127. Otherwise, the exit sta- + not be found, the exit status is 127. Otherwise, the exit sta- tus of the ccoommmmaanndd builtin is the exit status of _c_o_m_m_a_n_d. ccoommppggeenn [_o_p_t_i_o_n] [_w_o_r_d] - Generate possible completion matches for _w_o_r_d according to the - _o_p_t_i_o_ns, which may be any option accepted by the ccoommpplleettee - builtin with the exception of --pp and --rr, and write the matches - to the standard output. When using the --FF or --CC options, the - various shell variables set by the programmable completion - facilities, while available, will not have useful values. + Generate possible completion matches for _w_o_r_d according to the + _o_p_t_i_o_ns, which may be any option accepted by the ccoommpplleettee + builtin with the exception of --pp and --rr, and write the matches + to the standard output. When using the --FF or --CC options, the + various shell variables set by the programmable completion fa- + cilities, while available, will not have useful values. The matches will be generated in the same way as if the program- mable completion code had generated them directly from a comple- - tion specification with the same flags. If _w_o_r_d is specified, + tion specification with the same flags. If _w_o_r_d is specified, only those completions matching _w_o_r_d will be displayed. - The return value is true unless an invalid option is supplied, + The return value is true unless an invalid option is supplied, or no matches were generated. - ccoommpplleettee [--aabbccddeeffggjjkkssuuvv] [--oo _c_o_m_p_-_o_p_t_i_o_n] [--DDEEII] [--AA _a_c_t_i_o_n] [--GG _g_l_o_b_- - _p_a_t] [--WW _w_o_r_d_l_i_s_t] [--FF _f_u_n_c_t_i_o_n] [--CC _c_o_m_m_a_n_d] - [--XX _f_i_l_t_e_r_p_a_t] [--PP _p_r_e_f_i_x] [--SS _s_u_f_f_i_x] _n_a_m_e [_n_a_m_e _._._.] + ccoommpplleettee [--aabbccddeeffggjjkkssuuvv] [--oo _c_o_m_p_-_o_p_t_i_o_n] [--DDEEII] [--AA _a_c_t_i_o_n] [--GG _g_l_o_b_- + _p_a_t] [--WW _w_o_r_d_l_i_s_t] + [--FF _f_u_n_c_t_i_o_n] [--CC _c_o_m_m_a_n_d] [--XX _f_i_l_t_e_r_p_a_t] [--PP _p_r_e_f_i_x] [--SS _s_u_f_- + _f_i_x] _n_a_m_e [_n_a_m_e _._._.] ccoommpplleettee --pprr [--DDEEII] [_n_a_m_e ...] Specify how arguments to each _n_a_m_e should be completed. If the --pp option is supplied, or if no options are supplied, existing @@ -4421,7 +4491,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS indicates that other supplied options and actions should apply to ``empty'' command completion; that is, completion attempted on a blank line. The --II option indicates that other supplied - options and actions should apply to completion on the inital + options and actions should apply to completion on the initial non-assignment word on the line, or after a command delimiter such as ;; or ||, which is usually command name completion. If multiple options are supplied, the --DD option takes precedence @@ -4461,14 +4531,14 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS default). nnoossoorrtt Tell readline not to sort the list of possible completions alphabetically. - nnoossppaaccee Tell readline not to append a space (the - default) to words completed at the end of the + nnoossppaaccee Tell readline not to append a space (the de- + fault) to words completed at the end of the line. pplluussddiirrss After any matches defined by the compspec are - generated, directory name completion is - attempted and any matches are added to the - results of the other actions. + generated, directory name completion is at- + tempted and any matches are added to the results + of the other actions. --AA _a_c_t_i_o_n The _a_c_t_i_o_n may be one of the following to generate a list of possible completions: @@ -4517,13 +4587,13 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --FF _f_u_n_c_t_i_o_n The shell function _f_u_n_c_t_i_o_n is executed in the current shell environment. When the function is executed, the - first argument ($$11) is the name of the command whose - arguments are being completed, the second argument ($$22) - is the word being completed, and the third argument ($$33) - is the word preceding the word being completed on the - current command line. When it finishes, the possible - completions are retrieved from the value of the CCOOMMPPRREE-- - PPLLYY array variable. + first argument ($$11) is the name of the command whose ar- + guments are being completed, the second argument ($$22) is + the word being completed, and the third argument ($$33) is + the word preceding the word being completed on the cur- + rent command line. When it finishes, the possible com- + pletions are retrieved from the value of the CCOOMMPPRREEPPLLYY + array variable. --GG _g_l_o_b_p_a_t The pathname expansion pattern _g_l_o_b_p_a_t is expanded to generate the possible completions. @@ -4556,19 +4626,19 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS adding a completion specification. ccoommppoopptt [--oo _o_p_t_i_o_n] [--DDEEII] [++oo _o_p_t_i_o_n] [_n_a_m_e] - Modify completion options for each _n_a_m_e according to the - _o_p_t_i_o_ns, or for the currently-executing completion if no _n_a_m_es - are supplied. If no _o_p_t_i_o_ns are given, display the completion - options for each _n_a_m_e or the current completion. The possible - values of _o_p_t_i_o_n are those valid for the ccoommpplleettee builtin - described above. The --DD option indicates that other supplied - options should apply to the ``default'' command completion; that + Modify completion options for each _n_a_m_e according to the _o_p_- + _t_i_o_ns, or for the currently-executing completion if no _n_a_m_es are + supplied. If no _o_p_t_i_o_ns are given, display the completion op- + tions for each _n_a_m_e or the current completion. The possible + values of _o_p_t_i_o_n are those valid for the ccoommpplleettee builtin de- + scribed above. The --DD option indicates that other supplied op- + tions should apply to the ``default'' command completion; that is, completion attempted on a command for which no completion has previously been defined. The --EE option indicates that other supplied options should apply to ``empty'' command completion; that is, completion attempted on a blank line. The --II option indicates that other supplied options should apply to completion - on the inital non-assignment word on the line, or after a com- + on the initial non-assignment word on the line, or after a com- mand delimiter such as ;; or ||, which is usually command name completion. @@ -4579,13 +4649,13 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ccoonnttiinnuuee [_n] Resume the next iteration of the enclosing ffoorr, wwhhiillee, uunnttiill, or sseelleecctt loop. If _n is specified, resume at the _nth enclosing - loop. _n must be >= 1. If _n is greater than the number of - enclosing loops, the last enclosing loop (the ``top-level'' - loop) is resumed. The return value is 0 unless _n is not greater - than or equal to 1. + loop. _n must be >= 1. If _n is greater than the number of en- + closing loops, the last enclosing loop (the ``top-level'' loop) + is resumed. The return value is 0 unless _n is not greater than + or equal to 1. - ddeeccllaarree [--aaAAffFFggiillnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] - ttyyppeesseett [--aaAAffFFggiillnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] + ddeeccllaarree [--aaAAffFFggiiIIllnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] + ttyyppeesseett [--aaAAffFFggiiIIllnnrrttuuxx] [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] Declare variables and/or give them attributes. If no _n_a_m_es are given then display the values of variables. The --pp option will display the attributes and values of each _n_a_m_e. When --pp is used @@ -4593,18 +4663,22 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS are ignored. When --pp is supplied without _n_a_m_e arguments, it will display the attributes and values of all variables having the attributes specified by the additional options. If no other - options are supplied with --pp, ddeeccllaarree will display the - attributes and values of all shell variables. The --ff option - will restrict the display to shell functions. The --FF option - inhibits the display of function definitions; only the function - name and attributes are printed. If the eexxttddeebbuugg shell option - is enabled using sshhoopptt, the source file name and line number - where each _n_a_m_e is defined are displayed as well. The --FF option - implies --ff. The --gg option forces variables to be created or - modified at the global scope, even when ddeeccllaarree is executed in a - shell function. It is ignored in all other cases. The follow- - ing options can be used to restrict output to variables with the - specified attribute or to give variables attributes: + options are supplied with --pp, ddeeccllaarree will display the at- + tributes and values of all shell variables. The --ff option will + restrict the display to shell functions. The --FF option inhibits + the display of function definitions; only the function name and + attributes are printed. If the eexxttddeebbuugg shell option is enabled + using sshhoopptt, the source file name and line number where each + _n_a_m_e is defined are displayed as well. The --FF option implies + --ff. The --gg option forces variables to be created or modified at + the global scope, even when ddeeccllaarree is executed in a shell func- + tion. It is ignored in all other cases. The --II option causes + local variables to inherit the attributes (except the _n_a_m_e_r_e_f + attribute) and value of any existing variable with the same _n_a_m_e + at a surrounding scope. If there is no existing variable, the + local variable is initially unset. The following options can be + used to restrict output to variables with the specified attri- + bute or to give variables attributes: --aa Each _n_a_m_e is an indexed array variable (see AArrrraayyss above). --AA Each _n_a_m_e is an associative array variable (see AArrrraayyss @@ -4625,82 +4699,81 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS attribute cannot be applied to array variables. --rr Make _n_a_m_es readonly. These names cannot then be assigned values by subsequent assignment statements or unset. - --tt Give each _n_a_m_e the _t_r_a_c_e attribute. Traced functions - inherit the DDEEBBUUGG and RREETTUURRNN traps from the calling - shell. The trace attribute has no special meaning for - variables. - --uu When the variable is assigned a value, all lower-case - characters are converted to upper-case. The lower-case + --tt Give each _n_a_m_e the _t_r_a_c_e attribute. Traced functions in- + herit the DDEEBBUUGG and RREETTUURRNN traps from the calling shell. + The trace attribute has no special meaning for variables. + --uu When the variable is assigned a value, all lower-case + characters are converted to upper-case. The lower-case attribute is disabled. - --xx Mark _n_a_m_es for export to subsequent commands via the - environment. + --xx Mark _n_a_m_es for export to subsequent commands via the en- + vironment. - Using `+' instead of `-' turns off the attribute instead, with - the exceptions that ++aa and ++AA may not be used to destroy array - variables and ++rr will not remove the readonly attribute. When + Using `+' instead of `-' turns off the attribute instead, with + the exceptions that ++aa and ++AA may not be used to destroy array + variables and ++rr will not remove the readonly attribute. When used in a function, ddeeccllaarree and ttyyppeesseett make each _n_a_m_e local, as - with the llooccaall command, unless the --gg option is supplied. If a - variable name is followed by =_v_a_l_u_e, the value of the variable - is set to _v_a_l_u_e. When using --aa or --AA and the compound assign- - ment syntax to create array variables, additional attributes do - not take effect until subsequent assignments. The return value + with the llooccaall command, unless the --gg option is supplied. If a + variable name is followed by =_v_a_l_u_e, the value of the variable + is set to _v_a_l_u_e. When using --aa or --AA and the compound assign- + ment syntax to create array variables, additional attributes do + not take effect until subsequent assignments. The return value is 0 unless an invalid option is encountered, an attempt is made to define a function using ``-f foo=bar'', an attempt is made to - assign a value to a readonly variable, an attempt is made to - assign a value to an array variable without using the compound - assignment syntax (see AArrrraayyss above), one of the _n_a_m_e_s is not a - valid shell variable name, an attempt is made to turn off read- - only status for a readonly variable, an attempt is made to turn + assign a value to a readonly variable, an attempt is made to as- + sign a value to an array variable without using the compound as- + signment syntax (see AArrrraayyss above), one of the _n_a_m_e_s is not a + valid shell variable name, an attempt is made to turn off read- + only status for a readonly variable, an attempt is made to turn off array status for an array variable, or an attempt is made to display a non-existent function with --ff. ddiirrss [[--ccllppvv]] [[++_n]] [[--_n]] - Without options, displays the list of currently remembered - directories. The default display is on a single line with - directory names separated by spaces. Directories are added to - the list with the ppuusshhdd command; the ppooppdd command removes - entries from the list. The current directory is always the - first directory in the stack. - --cc Clears the directory stack by deleting all of the - entries. - --ll Produces a listing using full pathnames; the default + Without options, displays the list of currently remembered di- + rectories. The default display is on a single line with direc- + tory names separated by spaces. Directories are added to the + list with the ppuusshhdd command; the ppooppdd command removes entries + from the list. The current directory is always the first direc- + tory in the stack. + --cc Clears the directory stack by deleting all of the en- + tries. + --ll Produces a listing using full pathnames; the default listing format uses a tilde to denote the home directory. --pp Print the directory stack with one entry per line. - --vv Print the directory stack with one entry per line, pre- + --vv Print the directory stack with one entry per line, pre- fixing each entry with its index in the stack. ++_n Displays the _nth entry counting from the left of the list shown by ddiirrss when invoked without options, starting with zero. - --_n Displays the _nth entry counting from the right of the + --_n Displays the _nth entry counting from the right of the list shown by ddiirrss when invoked without options, starting with zero. - The return value is 0 unless an invalid option is supplied or _n + The return value is 0 unless an invalid option is supplied or _n indexes beyond the end of the directory stack. ddiissoowwnn [--aarr] [--hh] [_j_o_b_s_p_e_c ... | _p_i_d ... ] - Without options, remove each _j_o_b_s_p_e_c from the table of active - jobs. If _j_o_b_s_p_e_c is not present, and neither the --aa nor the --rr - option is supplied, the _c_u_r_r_e_n_t _j_o_b is used. If the --hh option - is given, each _j_o_b_s_p_e_c is not removed from the table, but is - marked so that SSIIGGHHUUPP is not sent to the job if the shell - receives a SSIIGGHHUUPP. If no _j_o_b_s_p_e_c is supplied, the --aa option - means to remove or mark all jobs; the --rr option without a _j_o_b_- - _s_p_e_c argument restricts operation to running jobs. The return - value is 0 unless a _j_o_b_s_p_e_c does not specify a valid job. + Without options, remove each _j_o_b_s_p_e_c from the table of active + jobs. If _j_o_b_s_p_e_c is not present, and neither the --aa nor the --rr + option is supplied, the _c_u_r_r_e_n_t _j_o_b is used. If the --hh option + is given, each _j_o_b_s_p_e_c is not removed from the table, but is + marked so that SSIIGGHHUUPP is not sent to the job if the shell re- + ceives a SSIIGGHHUUPP. If no _j_o_b_s_p_e_c is supplied, the --aa option means + to remove or mark all jobs; the --rr option without a _j_o_b_s_p_e_c ar- + gument restricts operation to running jobs. The return value is + 0 unless a _j_o_b_s_p_e_c does not specify a valid job. eecchhoo [--nneeEE] [_a_r_g ...] - Output the _a_r_gs, separated by spaces, followed by a newline. - The return status is 0 unless a write error occurs. If --nn is + Output the _a_r_gs, separated by spaces, followed by a newline. + The return status is 0 unless a write error occurs. If --nn is specified, the trailing newline is suppressed. If the --ee option - is given, interpretation of the following backslash-escaped - characters is enabled. The --EE option disables the interpreta- - tion of these escape characters, even on systems where they are - interpreted by default. The xxppgg__eecchhoo shell option may be used - to dynamically determine whether or not eecchhoo expands these - escape characters by default. eecchhoo does not interpret ---- to - mean the end of options. eecchhoo interprets the following escape - sequences: + is given, interpretation of the following backslash-escaped + characters is enabled. The --EE option disables the interpreta- + tion of these escape characters, even on systems where they are + interpreted by default. The xxppgg__eecchhoo shell option may be used + to dynamically determine whether or not eecchhoo expands these es- + cape characters by default. eecchhoo does not interpret ---- to mean + the end of options. eecchhoo interprets the following escape se- + quences: \\aa alert (bell) \\bb backspace \\cc suppress further output @@ -4712,89 +4785,92 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS \\tt horizontal tab \\vv vertical tab \\\\ backslash - \\00_n_n_n the eight-bit character whose value is the octal value + \\00_n_n_n the eight-bit character whose value is the octal value _n_n_n (zero to three octal digits) - \\xx_H_H the eight-bit character whose value is the hexadecimal + \\xx_H_H the eight-bit character whose value is the hexadecimal value _H_H (one or two hex digits) - \\uu_H_H_H_H the Unicode (ISO/IEC 10646) character whose value is the + \\uu_H_H_H_H the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value _H_H_H_H (one to four hex digits) \\UU_H_H_H_H_H_H_H_H - the Unicode (ISO/IEC 10646) character whose value is the + the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value _H_H_H_H_H_H_H_H (one to eight hex digits) eennaabbllee [--aa] [--ddnnppss] [--ff _f_i_l_e_n_a_m_e] [_n_a_m_e ...] - Enable and disable builtin shell commands. Disabling a builtin + Enable and disable builtin shell commands. Disabling a builtin allows a disk command which has the same name as a shell builtin - to be executed without specifying a full pathname, even though - the shell normally searches for builtins before disk commands. - If --nn is used, each _n_a_m_e is disabled; otherwise, _n_a_m_e_s are - enabled. For example, to use the tteesstt binary found via the PPAATTHH - instead of the shell builtin version, run ``enable -n test''. - The --ff option means to load the new builtin command _n_a_m_e from + to be executed without specifying a full pathname, even though + the shell normally searches for builtins before disk commands. + If --nn is used, each _n_a_m_e is disabled; otherwise, _n_a_m_e_s are en- + abled. For example, to use the tteesstt binary found via the PPAATTHH + instead of the shell builtin version, run ``enable -n test''. + The --ff option means to load the new builtin command _n_a_m_e from shared object _f_i_l_e_n_a_m_e, on systems that support dynamic loading. - The --dd option will delete a builtin previously loaded with --ff. + The --dd option will delete a builtin previously loaded with --ff. If no _n_a_m_e arguments are given, or if the --pp option is supplied, a list of shell builtins is printed. With no other option argu- - ments, the list consists of all enabled shell builtins. If --nn - is supplied, only disabled builtins are printed. If --aa is sup- - plied, the list printed includes all builtins, with an indica- - tion of whether or not each is enabled. If --ss is supplied, the - output is restricted to the POSIX _s_p_e_c_i_a_l builtins. The return - value is 0 unless a _n_a_m_e is not a shell builtin or there is an + ments, the list consists of all enabled shell builtins. If --nn + is supplied, only disabled builtins are printed. If --aa is sup- + plied, the list printed includes all builtins, with an indica- + tion of whether or not each is enabled. If --ss is supplied, the + output is restricted to the POSIX _s_p_e_c_i_a_l builtins. The return + value is 0 unless a _n_a_m_e is not a shell builtin or there is an error loading a new builtin from a shared object. eevvaall [_a_r_g ...] - The _a_r_gs are read and concatenated together into a single com- - mand. This command is then read and executed by the shell, and - its exit status is returned as the value of eevvaall. If there are + The _a_r_gs are read and concatenated together into a single com- + mand. This command is then read and executed by the shell, and + its exit status is returned as the value of eevvaall. If there are no _a_r_g_s, or only null arguments, eevvaall returns 0. eexxeecc [--ccll] [--aa _n_a_m_e] [_c_o_m_m_a_n_d [_a_r_g_u_m_e_n_t_s]] - If _c_o_m_m_a_n_d is specified, it replaces the shell. No new process - is created. The _a_r_g_u_m_e_n_t_s become the arguments to _c_o_m_m_a_n_d. If + If _c_o_m_m_a_n_d is specified, it replaces the shell. No new process + is created. The _a_r_g_u_m_e_n_t_s become the arguments to _c_o_m_m_a_n_d. If the --ll option is supplied, the shell places a dash at the begin- - ning of the zeroth argument passed to _c_o_m_m_a_n_d. This is what - _l_o_g_i_n(1) does. The --cc option causes _c_o_m_m_a_n_d to be executed with - an empty environment. If --aa is supplied, the shell passes _n_a_m_e + ning of the zeroth argument passed to _c_o_m_m_a_n_d. This is what _l_o_- + _g_i_n(1) does. The --cc option causes _c_o_m_m_a_n_d to be executed with + an empty environment. If --aa is supplied, the shell passes _n_a_m_e as the zeroth argument to the executed command. If _c_o_m_m_a_n_d can- - not be executed for some reason, a non-interactive shell exits, - unless the eexxeeccffaaiill shell option is enabled. In that case, it - returns failure. An interactive shell returns failure if the - file cannot be executed. A subshell exits unconditionally if - eexxeecc fails. If _c_o_m_m_a_n_d is not specified, any redirections take - effect in the current shell, and the return status is 0. If + not be executed for some reason, a non-interactive shell exits, + unless the eexxeeccffaaiill shell option is enabled. In that case, it + returns failure. An interactive shell returns failure if the + file cannot be executed. A subshell exits unconditionally if + eexxeecc fails. If _c_o_m_m_a_n_d is not specified, any redirections take + effect in the current shell, and the return status is 0. If there is a redirection error, the return status is 1. eexxiitt [_n] - Cause the shell to exit with a status of _n. If _n is omitted, + Cause the shell to exit with a status of _n. If _n is omitted, the exit status is that of the last command executed. A trap on EEXXIITT is executed before the shell terminates. eexxppoorrtt [--ffnn] [_n_a_m_e[=_w_o_r_d]] ... eexxppoorrtt --pp - The supplied _n_a_m_e_s are marked for automatic export to the envi- - ronment of subsequently executed commands. If the --ff option is - given, the _n_a_m_e_s refer to functions. If no _n_a_m_e_s are given, or - if the --pp option is supplied, a list of names of all exported - variables is printed. The --nn option causes the export property + The supplied _n_a_m_e_s are marked for automatic export to the envi- + ronment of subsequently executed commands. If the --ff option is + given, the _n_a_m_e_s refer to functions. If no _n_a_m_e_s are given, or + if the --pp option is supplied, a list of names of all exported + variables is printed. The --nn option causes the export property to be removed from each _n_a_m_e. If a variable name is followed by =_w_o_r_d, the value of the variable is set to _w_o_r_d. eexxppoorrtt returns an exit status of 0 unless an invalid option is encountered, one - of the _n_a_m_e_s is not a valid shell variable name, or --ff is sup- + of the _n_a_m_e_s is not a valid shell variable name, or --ff is sup- plied with a _n_a_m_e that is not a function. ffcc [--ee _e_n_a_m_e] [--llnnrr] [_f_i_r_s_t] [_l_a_s_t] ffcc --ss [_p_a_t=_r_e_p] [_c_m_d] - The first form selects a range of commands from _f_i_r_s_t to _l_a_s_t - from the history list and displays or edits and re-executes - them. _F_i_r_s_t and _l_a_s_t may be specified as a string (to locate - the last command beginning with that string) or as a number (an - index into the history list, where a negative number is used as - an offset from the current command number). If _l_a_s_t is not - specified, it is set to the current command for listing (so that - ``fc -l -10'' prints the last 10 commands) and to _f_i_r_s_t other- - wise. If _f_i_r_s_t is not specified, it is set to the previous com- - mand for editing and -16 for listing. + The first form selects a range of commands from _f_i_r_s_t to _l_a_s_t + from the history list and displays or edits and re-executes + them. _F_i_r_s_t and _l_a_s_t may be specified as a string (to locate + the last command beginning with that string) or as a number (an + index into the history list, where a negative number is used as + an offset from the current command number). When listing, a + _f_i_r_s_t or _l_a_s_t of 0 is equivalent to -1 and -0 is equivalent to + the current command (usually the ffcc command); otherwise 0 is + equivalent to -1 and -0 is invalid. If _l_a_s_t is not specified, + it is set to the current command for listing (so that ``fc -l + -10'' prints the last 10 commands) and to _f_i_r_s_t otherwise. If + _f_i_r_s_t is not specified, it is set to the previous command for + editing and -16 for listing. The --nn option suppresses the command numbers when listing. The --rr option reverses the order of the commands. If the --ll option @@ -4811,8 +4887,8 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS so that typing ``r cc'' runs the last command beginning with ``cc'' and typing ``r'' re-executes the last command. - If the first form is used, the return value is 0 unless an - invalid option is encountered or _f_i_r_s_t or _l_a_s_t specify history + If the first form is used, the return value is 0 unless an in- + valid option is encountered or _f_i_r_s_t or _l_a_s_t specify history lines out of range. If the --ee option is supplied, the return value is the value of the last command executed or failure if an error occurs with the temporary file of commands. If the second @@ -4829,73 +4905,74 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ify a valid job or _j_o_b_s_p_e_c specifies a job that was started without job control. - ggeettooppttss _o_p_t_s_t_r_i_n_g _n_a_m_e [_a_r_g_s] + ggeettooppttss _o_p_t_s_t_r_i_n_g _n_a_m_e [_a_r_g _._._.] ggeettooppttss is used by shell procedures to parse positional parame- ters. _o_p_t_s_t_r_i_n_g contains the option characters to be recog- - nized; if a character is followed by a colon, the option is - expected to have an argument, which should be separated from it - by white space. The colon and question mark characters may not - be used as option characters. Each time it is invoked, ggeettooppttss + nized; if a character is followed by a colon, the option is ex- + pected to have an argument, which should be separated from it by + white space. The colon and question mark characters may not be + used as option characters. Each time it is invoked, ggeettooppttss places the next option in the shell variable _n_a_m_e, initializing _n_a_m_e if it does not exist, and the index of the next argument to be processed into the variable OOPPTTIINNDD. OOPPTTIINNDD is initialized to - 1 each time the shell or a shell script is invoked. When an - option requires an argument, ggeettooppttss places that argument into - the variable OOPPTTAARRGG. The shell does not reset OOPPTTIINNDD automati- - cally; it must be manually reset between multiple calls to - ggeettooppttss within the same shell invocation if a new set of parame- - ters is to be used. + 1 each time the shell or a shell script is invoked. When an op- + tion requires an argument, ggeettooppttss places that argument into the + variable OOPPTTAARRGG. The shell does not reset OOPPTTIINNDD automatically; + it must be manually reset between multiple calls to ggeettooppttss + within the same shell invocation if a new set of parameters is + to be used. - When the end of options is encountered, ggeettooppttss exits with a - return value greater than zero. OOPPTTIINNDD is set to the index of - the first non-option argument, and _n_a_m_e is set to ?. + When the end of options is encountered, ggeettooppttss exits with a re- + turn value greater than zero. OOPPTTIINNDD is set to the index of the + first non-option argument, and _n_a_m_e is set to ?. ggeettooppttss normally parses the positional parameters, but if more - arguments are given in _a_r_g_s, ggeettooppttss parses those instead. - - ggeettooppttss can report errors in two ways. If the first character - of _o_p_t_s_t_r_i_n_g is a colon, _s_i_l_e_n_t error reporting is used. In - normal operation, diagnostic messages are printed when invalid - options or missing option arguments are encountered. If the - variable OOPPTTEERRRR is set to 0, no error messages will be dis- + arguments are supplied as _a_r_g values, ggeettooppttss parses those in- + stead. + + ggeettooppttss can report errors in two ways. If the first character + of _o_p_t_s_t_r_i_n_g is a colon, _s_i_l_e_n_t error reporting is used. In + normal operation, diagnostic messages are printed when invalid + options or missing option arguments are encountered. If the + variable OOPPTTEERRRR is set to 0, no error messages will be dis- played, even if the first character of _o_p_t_s_t_r_i_n_g is not a colon. If an invalid option is seen, ggeettooppttss places ? into _n_a_m_e and, if - not silent, prints an error message and unsets OOPPTTAARRGG. If - ggeettooppttss is silent, the option character found is placed in - OOPPTTAARRGG and no diagnostic message is printed. - - If a required argument is not found, and ggeettooppttss is not silent, - a question mark (??) is placed in _n_a_m_e, OOPPTTAARRGG is unset, and a - diagnostic message is printed. If ggeettooppttss is silent, then a - colon (::) is placed in _n_a_m_e and OOPPTTAARRGG is set to the option + not silent, prints an error message and unsets OOPPTTAARRGG. If + ggeettooppttss is silent, the option character found is placed in OOPP-- + TTAARRGG and no diagnostic message is printed. + + If a required argument is not found, and ggeettooppttss is not silent, + a question mark (??) is placed in _n_a_m_e, OOPPTTAARRGG is unset, and a + diagnostic message is printed. If ggeettooppttss is silent, then a + colon (::) is placed in _n_a_m_e and OOPPTTAARRGG is set to the option character found. - ggeettooppttss returns true if an option, specified or unspecified, is + ggeettooppttss returns true if an option, specified or unspecified, is found. It returns false if the end of options is encountered or an error occurs. hhaasshh [--llrr] [--pp _f_i_l_e_n_a_m_e] [--ddtt] [_n_a_m_e] Each time hhaasshh is invoked, the full pathname of the command _n_a_m_e - is determined by searching the directories in $$PPAATTHH and remem- + is determined by searching the directories in $$PPAATTHH and remem- bered. Any previously-remembered pathname is discarded. If the --pp option is supplied, no path search is performed, and _f_i_l_e_n_a_m_e - is used as the full filename of the command. The --rr option - causes the shell to forget all remembered locations. The --dd - option causes the shell to forget the remembered location of - each _n_a_m_e. If the --tt option is supplied, the full pathname to - which each _n_a_m_e corresponds is printed. If multiple _n_a_m_e argu- - ments are supplied with --tt, the _n_a_m_e is printed before the - hashed full pathname. The --ll option causes output to be dis- - played in a format that may be reused as input. If no arguments - are given, or if only --ll is supplied, information about remem- - bered commands is printed. The return status is true unless a - _n_a_m_e is not found or an invalid option is supplied. + is used as the full filename of the command. The --rr option + causes the shell to forget all remembered locations. The --dd op- + tion causes the shell to forget the remembered location of each + _n_a_m_e. If the --tt option is supplied, the full pathname to which + each _n_a_m_e corresponds is printed. If multiple _n_a_m_e arguments + are supplied with --tt, the _n_a_m_e is printed before the hashed full + pathname. The --ll option causes output to be displayed in a for- + mat that may be reused as input. If no arguments are given, or + if only --ll is supplied, information about remembered commands is + printed. The return status is true unless a _n_a_m_e is not found + or an invalid option is supplied. hheellpp [--ddmmss] [_p_a_t_t_e_r_n] - Display helpful information about builtin commands. If _p_a_t_t_e_r_n - is specified, hheellpp gives detailed help on all commands matching - _p_a_t_t_e_r_n; otherwise help for all the builtins and shell control + Display helpful information about builtin commands. If _p_a_t_t_e_r_n + is specified, hheellpp gives detailed help on all commands matching + _p_a_t_t_e_r_n; otherwise help for all the builtins and shell control structures is printed. --dd Display a short description of each _p_a_t_t_e_r_n --mm Display the description of each _p_a_t_t_e_r_n in a manpage-like @@ -4913,53 +4990,53 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS hhiissttoorryy --ss _a_r_g [_a_r_g _._._.] With no options, display the command history list with line num- bers. Lines listed with a ** have been modified. An argument of - _n lists only the last _n lines. If the shell variable HHIISSTTTTIIMMEE-- - FFOORRMMAATT is set and not null, it is used as a format string for - _s_t_r_f_t_i_m_e(3) to display the time stamp associated with each dis- - played history entry. No intervening blank is printed between - the formatted time stamp and the history line. If _f_i_l_e_n_a_m_e is - supplied, it is used as the name of the history file; if not, - the value of HHIISSTTFFIILLEE is used. Options, if supplied, have the + _n lists only the last _n lines. If the shell variable HHIISSTTTTIIMMEE-- + FFOORRMMAATT is set and not null, it is used as a format string for + _s_t_r_f_t_i_m_e(3) to display the time stamp associated with each dis- + played history entry. No intervening blank is printed between + the formatted time stamp and the history line. If _f_i_l_e_n_a_m_e is + supplied, it is used as the name of the history file; if not, + the value of HHIISSTTFFIILLEE is used. Options, if supplied, have the following meanings: --cc Clear the history list by deleting all the entries. --dd _o_f_f_s_e_t - Delete the history entry at position _o_f_f_s_e_t. If _o_f_f_s_e_t + Delete the history entry at position _o_f_f_s_e_t. If _o_f_f_s_e_t is negative, it is interpreted as relative to one greater than the last history position, so negative indices count - back from the end of the history, and an index of -1 + back from the end of the history, and an index of -1 refers to the current hhiissttoorryy --dd command. --dd _s_t_a_r_t-_e_n_d - Delete the history entries between positions _s_t_a_r_t and - _e_n_d, inclusive. Positive and negative values for _s_t_a_r_t + Delete the history entries between positions _s_t_a_r_t and + _e_n_d, inclusive. Positive and negative values for _s_t_a_r_t and _e_n_d are interpreted as described above. - --aa Append the ``new'' history lines to the history file. - These are history lines entered since the beginning of + --aa Append the ``new'' history lines to the history file. + These are history lines entered since the beginning of the current bbaasshh session, but not already appended to the history file. - --nn Read the history lines not already read from the history - file into the current history list. These are lines - appended to the history file since the beginning of the + --nn Read the history lines not already read from the history + file into the current history list. These are lines ap- + pended to the history file since the beginning of the current bbaasshh session. - --rr Read the contents of the history file and append them to + --rr Read the contents of the history file and append them to the current history list. --ww Write the current history list to the history file, over- writing the history file's contents. - --pp Perform history substitution on the following _a_r_g_s and - display the result on the standard output. Does not - store the results in the history list. Each _a_r_g must be + --pp Perform history substitution on the following _a_r_g_s and + display the result on the standard output. Does not + store the results in the history list. Each _a_r_g must be quoted to disable normal history expansion. - --ss Store the _a_r_g_s in the history list as a single entry. - The last command in the history list is removed before + --ss Store the _a_r_g_s in the history list as a single entry. + The last command in the history list is removed before the _a_r_g_s are added. - If the HHIISSTTTTIIMMEEFFOORRMMAATT variable is set, the time stamp informa- - tion associated with each history entry is written to the his- - tory file, marked with the history comment character. When the - history file is read, lines beginning with the history comment - character followed immediately by a digit are interpreted as + If the HHIISSTTTTIIMMEEFFOORRMMAATT variable is set, the time stamp informa- + tion associated with each history entry is written to the his- + tory file, marked with the history comment character. When the + history file is read, lines beginning with the history comment + character followed immediately by a digit are interpreted as timestamps for the following history entry. The return value is 0 unless an invalid option is encountered, an error occurs while - reading or writing the history file, an invalid _o_f_f_s_e_t is sup- + reading or writing the history file, an invalid _o_f_f_s_e_t is sup- plied as an argument to --dd, or the history expansion supplied as an argument to --pp fails. @@ -4968,147 +5045,154 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS The first form lists the active jobs. The options have the fol- lowing meanings: --ll List process IDs in addition to the normal information. - --nn Display information only about jobs that have changed + --nn Display information only about jobs that have changed status since the user was last notified of their status. - --pp List only the process ID of the job's process group + --pp List only the process ID of the job's process group leader. --rr Display only running jobs. --ss Display only stopped jobs. - If _j_o_b_s_p_e_c is given, output is restricted to information about - that job. The return status is 0 unless an invalid option is + If _j_o_b_s_p_e_c is given, output is restricted to information about + that job. The return status is 0 unless an invalid option is encountered or an invalid _j_o_b_s_p_e_c is supplied. If the --xx option is supplied, jjoobbss replaces any _j_o_b_s_p_e_c found in - _c_o_m_m_a_n_d or _a_r_g_s with the corresponding process group ID, and - executes _c_o_m_m_a_n_d passing it _a_r_g_s, returning its exit status. + _c_o_m_m_a_n_d or _a_r_g_s with the corresponding process group ID, and ex- + ecutes _c_o_m_m_a_n_d passing it _a_r_g_s, returning its exit status. kkiillll [--ss _s_i_g_s_p_e_c | --nn _s_i_g_n_u_m | --_s_i_g_s_p_e_c] [_p_i_d | _j_o_b_s_p_e_c] ... kkiillll --ll|--LL [_s_i_g_s_p_e_c | _e_x_i_t___s_t_a_t_u_s] - Send the signal named by _s_i_g_s_p_e_c or _s_i_g_n_u_m to the processes - named by _p_i_d or _j_o_b_s_p_e_c. _s_i_g_s_p_e_c is either a case-insensitive - signal name such as SSIIGGKKIILLLL (with or without the SSIIGG prefix) or - a signal number; _s_i_g_n_u_m is a signal number. If _s_i_g_s_p_e_c is not - present, then SSIIGGTTEERRMM is assumed. An argument of --ll lists the - signal names. If any arguments are supplied when --ll is given, - the names of the signals corresponding to the arguments are + Send the signal named by _s_i_g_s_p_e_c or _s_i_g_n_u_m to the processes + named by _p_i_d or _j_o_b_s_p_e_c. _s_i_g_s_p_e_c is either a case-insensitive + signal name such as SSIIGGKKIILLLL (with or without the SSIIGG prefix) or + a signal number; _s_i_g_n_u_m is a signal number. If _s_i_g_s_p_e_c is not + present, then SSIIGGTTEERRMM is assumed. An argument of --ll lists the + signal names. If any arguments are supplied when --ll is given, + the names of the signals corresponding to the arguments are listed, and the return status is 0. The _e_x_i_t___s_t_a_t_u_s argument to - --ll is a number specifying either a signal number or the exit - status of a process terminated by a signal. The --LL option is - equivalent to --ll. kkiillll returns true if at least one signal was - successfully sent, or false if an error occurs or an invalid - option is encountered. + --ll is a number specifying either a signal number or the exit + status of a process terminated by a signal. The --LL option is + equivalent to --ll. kkiillll returns true if at least one signal was + successfully sent, or false if an error occurs or an invalid op- + tion is encountered. lleett _a_r_g [_a_r_g ...] Each _a_r_g is an arithmetic expression to be evaluated (see AARRIITTHH-- - MMEETTIICC EEVVAALLUUAATTIIOONN above). If the last _a_r_g evaluates to 0, lleett + MMEETTIICC EEVVAALLUUAATTIIOONN above). If the last _a_r_g evaluates to 0, lleett returns 1; 0 is returned otherwise. llooccaall [_o_p_t_i_o_n] [_n_a_m_e[=_v_a_l_u_e] ... | - ] - For each argument, a local variable named _n_a_m_e is created, and - assigned _v_a_l_u_e. The _o_p_t_i_o_n can be any of the options accepted + For each argument, a local variable named _n_a_m_e is created, and + assigned _v_a_l_u_e. The _o_p_t_i_o_n can be any of the options accepted by ddeeccllaarree. When llooccaall is used within a function, it causes the - variable _n_a_m_e to have a visible scope restricted to that func- - tion and its children. If _n_a_m_e is -, the set of shell options - is made local to the function in which llooccaall is invoked: shell - options changed using the sseett builtin inside the function are - restored to their original values when the function returns. - With no operands, llooccaall writes a list of local variables to the - standard output. It is an error to use llooccaall when not within a - function. The return status is 0 unless llooccaall is used outside a - function, an invalid _n_a_m_e is supplied, or _n_a_m_e is a readonly - variable. + variable _n_a_m_e to have a visible scope restricted to that func- + tion and its children. If _n_a_m_e is -, the set of shell options + is made local to the function in which llooccaall is invoked: shell + options changed using the sseett builtin inside the function are + restored to their original values when the function returns. + The restore is effected as if a series of sseett commands were exe- + cuted to restore the values that were in place before the func- + tion. With no operands, llooccaall writes a list of local variables + to the standard output. It is an error to use llooccaall when not + within a function. The return status is 0 unless llooccaall is used + outside a function, an invalid _n_a_m_e is supplied, or _n_a_m_e is a + readonly variable. llooggoouutt Exit a login shell. - mmaappffiillee [--dd _d_e_l_i_m] [--nn _c_o_u_n_t] [--OO _o_r_i_g_i_n] [--ss _c_o_u_n_t] [--tt] [--uu _f_d] [--CC + mmaappffiillee [--dd _d_e_l_i_m] [--nn _c_o_u_n_t] [--OO _o_r_i_g_i_n] [--ss _c_o_u_n_t] [--tt] [--uu _f_d] [--CC _c_a_l_l_b_a_c_k] [--cc _q_u_a_n_t_u_m] [_a_r_r_a_y] rreeaaddaarrrraayy [--dd _d_e_l_i_m] [--nn _c_o_u_n_t] [--OO _o_r_i_g_i_n] [--ss _c_o_u_n_t] [--tt] [--uu _f_d] [--CC _c_a_l_l_b_a_c_k] [--cc _q_u_a_n_t_u_m] [_a_r_r_a_y] - Read lines from the standard input into the indexed array vari- - able _a_r_r_a_y, or from file descriptor _f_d if the --uu option is sup- - plied. The variable MMAAPPFFIILLEE is the default _a_r_r_a_y. Options, if + Read lines from the standard input into the indexed array vari- + able _a_r_r_a_y, or from file descriptor _f_d if the --uu option is sup- + plied. The variable MMAAPPFFIILLEE is the default _a_r_r_a_y. Options, if supplied, have the following meanings: - --dd The first character of _d_e_l_i_m is used to terminate each - input line, rather than newline. If _d_e_l_i_m is the empty + --dd The first character of _d_e_l_i_m is used to terminate each + input line, rather than newline. If _d_e_l_i_m is the empty string, mmaappffiillee will terminate a line when it reads a NUL character. - --nn Copy at most _c_o_u_n_t lines. If _c_o_u_n_t is 0, all lines are + --nn Copy at most _c_o_u_n_t lines. If _c_o_u_n_t is 0, all lines are copied. - --OO Begin assigning to _a_r_r_a_y at index _o_r_i_g_i_n. The default + --OO Begin assigning to _a_r_r_a_y at index _o_r_i_g_i_n. The default index is 0. --ss Discard the first _c_o_u_n_t lines read. - --tt Remove a trailing _d_e_l_i_m (default newline) from each line + --tt Remove a trailing _d_e_l_i_m (default newline) from each line read. - --uu Read lines from file descriptor _f_d instead of the stan- + --uu Read lines from file descriptor _f_d instead of the stan- dard input. - --CC Evaluate _c_a_l_l_b_a_c_k each time _q_u_a_n_t_u_m lines are read. The + --CC Evaluate _c_a_l_l_b_a_c_k each time _q_u_a_n_t_u_m lines are read. The --cc option specifies _q_u_a_n_t_u_m. - --cc Specify the number of lines read between each call to + --cc Specify the number of lines read between each call to _c_a_l_l_b_a_c_k. - If --CC is specified without --cc, the default quantum is 5000. + If --CC is specified without --cc, the default quantum is 5000. When _c_a_l_l_b_a_c_k is evaluated, it is supplied the index of the next array element to be assigned and the line to be assigned to that - element as additional arguments. _c_a_l_l_b_a_c_k is evaluated after + element as additional arguments. _c_a_l_l_b_a_c_k is evaluated after the line is read but before the array element is assigned. - If not supplied with an explicit origin, mmaappffiillee will clear - _a_r_r_a_y before assigning to it. + If not supplied with an explicit origin, mmaappffiillee will clear _a_r_- + _r_a_y before assigning to it. - mmaappffiillee returns successfully unless an invalid option or option - argument is supplied, _a_r_r_a_y is invalid or unassignable, or if + mmaappffiillee returns successfully unless an invalid option or option + argument is supplied, _a_r_r_a_y is invalid or unassignable, or if _a_r_r_a_y is not an indexed array. ppooppdd [-nn] [+_n] [-_n] - Removes entries from the directory stack. With no arguments, - removes the top directory from the stack, and performs a ccdd to + Removes entries from the directory stack. With no arguments, + removes the top directory from the stack, and performs a ccdd to the new top directory. Arguments, if supplied, have the follow- ing meanings: - --nn Suppresses the normal change of directory when removing - directories from the stack, so that only the stack is - manipulated. - ++_n Removes the _nth entry counting from the left of the list - shown by ddiirrss, starting with zero. For example: ``popd + --nn Suppresses the normal change of directory when removing + directories from the stack, so that only the stack is ma- + nipulated. + ++_n Removes the _nth entry counting from the left of the list + shown by ddiirrss, starting with zero. For example: ``popd +0'' removes the first directory, ``popd +1'' the second. --_n Removes the _nth entry counting from the right of the list - shown by ddiirrss, starting with zero. For example: ``popd - -0'' removes the last directory, ``popd -1'' the next to + shown by ddiirrss, starting with zero. For example: ``popd + -0'' removes the last directory, ``popd -1'' the next to last. - If the ppooppdd command is successful, a ddiirrss is performed as well, - and the return status is 0. ppooppdd returns false if an invalid + If the ppooppdd command is successful, a ddiirrss is performed as well, + and the return status is 0. ppooppdd returns false if an invalid option is encountered, the directory stack is empty, a non-exis- tent directory stack entry is specified, or the directory change fails. pprriinnttff [--vv _v_a_r] _f_o_r_m_a_t [_a_r_g_u_m_e_n_t_s] - Write the formatted _a_r_g_u_m_e_n_t_s to the standard output under the - control of the _f_o_r_m_a_t. The --vv option causes the output to be - assigned to the variable _v_a_r rather than being printed to the + Write the formatted _a_r_g_u_m_e_n_t_s to the standard output under the + control of the _f_o_r_m_a_t. The --vv option causes the output to be + assigned to the variable _v_a_r rather than being printed to the standard output. - The _f_o_r_m_a_t is a character string which contains three types of - objects: plain characters, which are simply copied to standard - output, character escape sequences, which are converted and - copied to the standard output, and format specifications, each - of which causes printing of the next successive _a_r_g_u_m_e_n_t. In + The _f_o_r_m_a_t is a character string which contains three types of + objects: plain characters, which are simply copied to standard + output, character escape sequences, which are converted and + copied to the standard output, and format specifications, each + of which causes printing of the next successive _a_r_g_u_m_e_n_t. In addition to the standard _p_r_i_n_t_f(1) format specifications, pprriinnttff interprets the following extensions: %%bb causes pprriinnttff to expand backslash escape sequences in the corresponding _a_r_g_u_m_e_n_t in the same way as eecchhoo --ee. - %%qq causes pprriinnttff to output the corresponding _a_r_g_u_m_e_n_t in a + %%qq causes pprriinnttff to output the corresponding _a_r_g_u_m_e_n_t in a format that can be reused as shell input. %%((_d_a_t_e_f_m_t))TT - causes pprriinnttff to output the date-time string resulting - from using _d_a_t_e_f_m_t as a format string for _s_t_r_f_t_i_m_e(3). + causes pprriinnttff to output the date-time string resulting + from using _d_a_t_e_f_m_t as a format string for _s_t_r_f_t_i_m_e(3). The corresponding _a_r_g_u_m_e_n_t is an integer representing the - number of seconds since the epoch. Two special argument - values may be used: -1 represents the current time, and - -2 represents the time the shell was invoked. If no - argument is specified, conversion behaves as if -1 had - been given. This is an exception to the usual pprriinnttff - behavior. + number of seconds since the epoch. Two special argument + values may be used: -1 represents the current time, and + -2 represents the time the shell was invoked. If no ar- + gument is specified, conversion behaves as if -1 had been + given. This is an exception to the usual pprriinnttff behav- + ior. + + The %b, %q, and %T directives all use the field width and preci- + sion arguments from the format specification and write that many + bytes from (or use that wide a field for) the expanded argument, + which usually contains more characters than the original. Arguments to non-string format specifiers are treated as C con- stants, except that a leading plus or minus sign is allowed, and @@ -5125,8 +5209,8 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS ppuusshhdd [--nn] [_d_i_r] Adds a directory to the top of the directory stack, or rotates the stack, making the new top of the stack the current working - directory. With no arguments, ppuusshhdd exchanges the top two - directories and returns 0, unless the directory stack is empty. + directory. With no arguments, ppuusshhdd exchanges the top two di- + rectories and returns 0, unless the directory stack is empty. Arguments, if supplied, have the following meanings: --nn Suppresses the normal change of directory when rotating or adding directories to the stack, so that only the @@ -5154,33 +5238,33 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS is supplied or the --oo pphhyyssiiccaall option to the sseett builtin command is enabled. If the --LL option is used, the pathname printed may contain symbolic links. The return status is 0 unless an error - occurs while reading the name of the current directory or an - invalid option is supplied. + occurs while reading the name of the current directory or an in- + valid option is supplied. rreeaadd [--eerrss] [--aa _a_n_a_m_e] [--dd _d_e_l_i_m] [--ii _t_e_x_t] [--nn _n_c_h_a_r_s] [--NN _n_c_h_a_r_s] [--pp _p_r_o_m_p_t] [--tt _t_i_m_e_o_u_t] [--uu _f_d] [_n_a_m_e ...] - One line is read from the standard input, or from the file - descriptor _f_d supplied as an argument to the --uu option, split - into words as described above under WWoorrdd SSpplliittttiinngg, and the - first word is assigned to the first _n_a_m_e, the second word to the - second _n_a_m_e, and so on. If there are more words than names, the + One line is read from the standard input, or from the file de- + scriptor _f_d supplied as an argument to the --uu option, split into + words as described above under WWoorrdd SSpplliittttiinngg, and the first + word is assigned to the first _n_a_m_e, the second word to the sec- + ond _n_a_m_e, and so on. If there are more words than names, the remaining words and their intervening delimiters are assigned to the last _n_a_m_e. If there are fewer words read from the input stream than names, the remaining names are assigned empty val- ues. The characters in IIFFSS are used to split the line into - words using the same rules the shell uses for expansion - (described above under WWoorrdd SSpplliittttiinngg). The backslash character + words using the same rules the shell uses for expansion (de- + scribed above under WWoorrdd SSpplliittttiinngg). The backslash character (\\) may be used to remove any special meaning for the next char- acter read and for line continuation. Options, if supplied, have the following meanings: --aa _a_n_a_m_e The words are assigned to sequential indices of the array variable _a_n_a_m_e, starting at 0. _a_n_a_m_e is unset before any - new values are assigned. Other _n_a_m_e arguments are - ignored. + new values are assigned. Other _n_a_m_e arguments are ig- + nored. --dd _d_e_l_i_m - The first character of _d_e_l_i_m is used to terminate the - input line, rather than newline. If _d_e_l_i_m is the empty + The first character of _d_e_l_i_m is used to terminate the in- + put line, rather than newline. If _d_e_l_i_m is the empty string, rreeaadd will terminate a line when it reads a NUL character. --ee If the standard input is coming from a terminal, rreeaaddlliinnee @@ -5225,128 +5309,129 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS reading input from a terminal, pipe, or other special file; it has no effect when reading from regular files. If rreeaadd times out, rreeaadd saves any partial input read into - the specified variable _n_a_m_e. If _t_i_m_e_o_u_t is 0, rreeaadd - returns immediately, without trying to read any data. - The exit status is 0 if input is available on the speci- - fied file descriptor, non-zero otherwise. The exit sta- - tus is greater than 128 if the timeout is exceeded. + the specified variable _n_a_m_e. If _t_i_m_e_o_u_t is 0, rreeaadd re- + turns immediately, without trying to read any data. The + exit status is 0 if input is available on the specified + file descriptor, non-zero otherwise. The exit status is + greater than 128 if the timeout is exceeded. --uu _f_d Read input from file descriptor _f_d. - If no _n_a_m_e_s are supplied, the line read is assigned to the vari- - able RREEPPLLYY. The exit status is zero, unless end-of-file is - encountered, rreeaadd times out (in which case the status is greater - than 128), a variable assignment error (such as assigning to a - readonly variable) occurs, or an invalid file descriptor is sup- - plied as the argument to --uu. + If no _n_a_m_e_s are supplied, the line read, without the ending de- + limiter but otherwise unmodified, is assigned to the variable + RREEPPLLYY. The exit status is zero, unless end-of-file is encoun- + tered, rreeaadd times out (in which case the status is greater than + 128), a variable assignment error (such as assigning to a read- + only variable) occurs, or an invalid file descriptor is supplied + as the argument to --uu. rreeaaddoonnllyy [--aaAAff] [--pp] [_n_a_m_e[=_w_o_r_d] ...] - The given _n_a_m_e_s are marked readonly; the values of these _n_a_m_e_s - may not be changed by subsequent assignment. If the --ff option - is supplied, the functions corresponding to the _n_a_m_e_s are so - marked. The --aa option restricts the variables to indexed - arrays; the --AA option restricts the variables to associative - arrays. If both options are supplied, --AA takes precedence. If - no _n_a_m_e arguments are given, or if the --pp option is supplied, a + The given _n_a_m_e_s are marked readonly; the values of these _n_a_m_e_s + may not be changed by subsequent assignment. If the --ff option + is supplied, the functions corresponding to the _n_a_m_e_s are so + marked. The --aa option restricts the variables to indexed ar- + rays; the --AA option restricts the variables to associative ar- + rays. If both options are supplied, --AA takes precedence. If no + _n_a_m_e arguments are given, or if the --pp option is supplied, a list of all readonly names is printed. The other options may be - used to restrict the output to a subset of the set of readonly - names. The --pp option causes output to be displayed in a format - that may be reused as input. If a variable name is followed by - =_w_o_r_d, the value of the variable is set to _w_o_r_d. The return - status is 0 unless an invalid option is encountered, one of the + used to restrict the output to a subset of the set of readonly + names. The --pp option causes output to be displayed in a format + that may be reused as input. If a variable name is followed by + =_w_o_r_d, the value of the variable is set to _w_o_r_d. The return + status is 0 unless an invalid option is encountered, one of the _n_a_m_e_s is not a valid shell variable name, or --ff is supplied with a _n_a_m_e that is not a function. rreettuurrnn [_n] - Causes a function to stop executing and return the value speci- - fied by _n to its caller. If _n is omitted, the return status is - that of the last command executed in the function body. If - rreettuurrnn is executed by a trap handler, the last command used to - determine the status is the last command executed before the - trap handler. If rreettuurrnn is executed during a DDEEBBUUGG trap, the - last command used to determine the status is the last command - executed by the trap handler before rreettuurrnn was invoked. If - rreettuurrnn is used outside a function, but during execution of a - script by the .. (ssoouurrccee) command, it causes the shell to stop - executing that script and return either _n or the exit status of - the last command executed within the script as the exit status - of the script. If _n is supplied, the return value is its least - significant 8 bits. The return status is non-zero if rreettuurrnn is - supplied a non-numeric argument, or is used outside a function - and not during execution of a script by .. or ssoouurrccee. Any com- - mand associated with the RREETTUURRNN trap is executed before execu- - tion resumes after the function or script. + Causes a function to stop executing and return the value speci- + fied by _n to its caller. If _n is omitted, the return status is + that of the last command executed in the function body. If rree-- + ttuurrnn is executed by a trap handler, the last command used to de- + termine the status is the last command executed before the trap + handler. If rreettuurrnn is executed during a DDEEBBUUGG trap, the last + command used to determine the status is the last command exe- + cuted by the trap handler before rreettuurrnn was invoked. If rreettuurrnn + is used outside a function, but during execution of a script by + the .. (ssoouurrccee) command, it causes the shell to stop executing + that script and return either _n or the exit status of the last + command executed within the script as the exit status of the + script. If _n is supplied, the return value is its least signif- + icant 8 bits. The return status is non-zero if rreettuurrnn is sup- + plied a non-numeric argument, or is used outside a function and + not during execution of a script by .. or ssoouurrccee. Any command + associated with the RREETTUURRNN trap is executed before execution re- + sumes after the function or script. sseett [----aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [--oo _o_p_t_i_o_n_-_n_a_m_e] [_a_r_g ...] sseett [++aabbeeffhhkkmmnnppttuuvvxxBBCCEEHHPPTT] [++oo _o_p_t_i_o_n_-_n_a_m_e] [_a_r_g ...] - Without options, the name and value of each shell variable are + Without options, the name and value of each shell variable are displayed in a format that can be reused as input for setting or resetting the currently-set variables. Read-only variables can- - not be reset. In _p_o_s_i_x _m_o_d_e, only shell variables are listed. - The output is sorted according to the current locale. When - options are specified, they set or unset shell attributes. Any - arguments remaining after option processing are treated as val- + not be reset. In _p_o_s_i_x _m_o_d_e, only shell variables are listed. + The output is sorted according to the current locale. When op- + tions are specified, they set or unset shell attributes. Any + arguments remaining after option processing are treated as val- ues for the positional parameters and are assigned, in order, to - $$11, $$22, ...... $$_n. Options, if specified, have the following + $$11, $$22, ...... $$_n. Options, if specified, have the following meanings: --aa Each variable or function that is created or modified is - given the export attribute and marked for export to the + given the export attribute and marked for export to the environment of subsequent commands. - --bb Report the status of terminated background jobs immedi- + --bb Report the status of terminated background jobs immedi- ately, rather than before the next primary prompt. This is effective only when job control is enabled. - --ee Exit immediately if a _p_i_p_e_l_i_n_e (which may consist of a - single _s_i_m_p_l_e _c_o_m_m_a_n_d), a _l_i_s_t, or a _c_o_m_p_o_u_n_d _c_o_m_m_a_n_d + --ee Exit immediately if a _p_i_p_e_l_i_n_e (which may consist of a + single _s_i_m_p_l_e _c_o_m_m_a_n_d), a _l_i_s_t, or a _c_o_m_p_o_u_n_d _c_o_m_m_a_n_d (see SSHHEELLLL GGRRAAMMMMAARR above), exits with a non-zero status. - The shell does not exit if the command that fails is - part of the command list immediately following a wwhhiillee - or uunnttiill keyword, part of the test following the iiff or - eelliiff reserved words, part of any command executed in a - &&&& or |||| list except the command following the final &&&& + The shell does not exit if the command that fails is + part of the command list immediately following a wwhhiillee + or uunnttiill keyword, part of the test following the iiff or + eelliiff reserved words, part of any command executed in a + &&&& or |||| list except the command following the final &&&& or ||||, any command in a pipeline but the last, or if the - command's return value is being inverted with !!. If a - compound command other than a subshell returns a non- - zero status because a command failed while --ee was being - ignored, the shell does not exit. A trap on EERRRR, if - set, is executed before the shell exits. This option + command's return value is being inverted with !!. If a + compound command other than a subshell returns a non- + zero status because a command failed while --ee was being + ignored, the shell does not exit. A trap on EERRRR, if + set, is executed before the shell exits. This option applies to the shell environment and each subshell envi- - ronment separately (see CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENNTT + ronment separately (see CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENNTT above), and may cause subshells to exit before executing all the commands in the subshell. - If a compound command or shell function executes in a - context where --ee is being ignored, none of the commands - executed within the compound command or function body - will be affected by the --ee setting, even if --ee is set - and a command returns a failure status. If a compound - command or shell function sets --ee while executing in a - context where --ee is ignored, that setting will not have - any effect until the compound command or the command + If a compound command or shell function executes in a + context where --ee is being ignored, none of the commands + executed within the compound command or function body + will be affected by the --ee setting, even if --ee is set + and a command returns a failure status. If a compound + command or shell function sets --ee while executing in a + context where --ee is ignored, that setting will not have + any effect until the compound command or the command containing the function call completes. --ff Disable pathname expansion. - --hh Remember the location of commands as they are looked up + --hh Remember the location of commands as they are looked up for execution. This is enabled by default. - --kk All arguments in the form of assignment statements are - placed in the environment for a command, not just those + --kk All arguments in the form of assignment statements are + placed in the environment for a command, not just those that precede the command name. - --mm Monitor mode. Job control is enabled. This option is - on by default for interactive shells on systems that - support it (see JJOOBB CCOONNTTRROOLL above). All processes run + --mm Monitor mode. Job control is enabled. This option is + on by default for interactive shells on systems that + support it (see JJOOBB CCOONNTTRROOLL above). All processes run in a separate process group. When a background job com- pletes, the shell prints a line containing its exit sta- tus. --nn Read commands but do not execute them. This may be used - to check a shell script for syntax errors. This is - ignored by interactive shells. + to check a shell script for syntax errors. This is ig- + nored by interactive shells. --oo _o_p_t_i_o_n_-_n_a_m_e The _o_p_t_i_o_n_-_n_a_m_e can be one of the following: aalllleexxppoorrtt Same as --aa. bbrraacceeeexxppaanndd Same as --BB. - eemmaaccss Use an emacs-style command line editing inter- + eemmaaccss Use an emacs-style command line editing inter- face. This is enabled by default when the shell is interactive, unless the shell is started with - the ----nnooeeddiittiinngg option. This also affects the + the ----nnooeeddiittiinngg option. This also affects the editing interface used for rreeaadd --ee. eerrrreexxiitt Same as --ee. eerrrrttrraaccee @@ -5360,9 +5445,9 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS HHIISSTTOORRYY. This option is on by default in inter- active shells. iiggnnoorreeeeooff - The effect is as if the shell command - ``IGNOREEOF=10'' had been executed (see SShheellll - VVaarriiaabblleess above). + The effect is as if the shell command ``IG- + NOREEOF=10'' had been executed (see SShheellll VVaarrii-- + aabblleess above). kkeeyywwoorrdd Same as --kk. mmoonniittoorr Same as --mm. nnoocclloobbbbeerr @@ -5376,450 +5461,452 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS pphhyyssiiccaall Same as --PP. ppiippeeffaaiill - If set, the return value of a pipeline is the - value of the last (rightmost) command to exit - with a non-zero status, or zero if all commands - in the pipeline exit successfully. This option + If set, the return value of a pipeline is the + value of the last (rightmost) command to exit + with a non-zero status, or zero if all commands + in the pipeline exit successfully. This option is disabled by default. - ppoossiixx Change the behavior of bbaasshh where the default - operation differs from the POSIX standard to - match the standard (_p_o_s_i_x _m_o_d_e). See SSEEEE AALLSSOO + ppoossiixx Change the behavior of bbaasshh where the default + operation differs from the POSIX standard to + match the standard (_p_o_s_i_x _m_o_d_e). See SSEEEE AALLSSOO below for a reference to a document that details how posix mode affects bash's behavior. pprriivviilleeggeedd Same as --pp. vveerrbboossee Same as --vv. - vvii Use a vi-style command line editing interface. + vvii Use a vi-style command line editing interface. This also affects the editing interface used for rreeaadd --ee. xxttrraaccee Same as --xx. If --oo is supplied with no _o_p_t_i_o_n_-_n_a_m_e, the values of the - current options are printed. If ++oo is supplied with no - _o_p_t_i_o_n_-_n_a_m_e, a series of sseett commands to recreate the - current option settings is displayed on the standard + current options are printed. If ++oo is supplied with no + _o_p_t_i_o_n_-_n_a_m_e, a series of sseett commands to recreate the + current option settings is displayed on the standard output. - --pp Turn on _p_r_i_v_i_l_e_g_e_d mode. In this mode, the $$EENNVV and - $$BBAASSHH__EENNVV files are not processed, shell functions are - not inherited from the environment, and the SSHHEELLLLOOPPTTSS, - BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they - appear in the environment, are ignored. If the shell is - started with the effective user (group) id not equal to - the real user (group) id, and the --pp option is not sup- + --pp Turn on _p_r_i_v_i_l_e_g_e_d mode. In this mode, the $$EENNVV and + $$BBAASSHH__EENNVV files are not processed, shell functions are + not inherited from the environment, and the SSHHEELLLLOOPPTTSS, + BBAASSHHOOPPTTSS, CCDDPPAATTHH, and GGLLOOBBIIGGNNOORREE variables, if they ap- + pear in the environment, are ignored. If the shell is + started with the effective user (group) id not equal to + the real user (group) id, and the --pp option is not sup- plied, these actions are taken and the effective user id - is set to the real user id. If the --pp option is sup- - plied at startup, the effective user id is not reset. - Turning this option off causes the effective user and + is set to the real user id. If the --pp option is sup- + plied at startup, the effective user id is not reset. + Turning this option off causes the effective user and group ids to be set to the real user and group ids. --tt Exit after reading and executing one command. --uu Treat unset variables and parameters other than the spe- - cial parameters "@" and "*" as an error when performing - parameter expansion. If expansion is attempted on an - unset variable or parameter, the shell prints an error - message, and, if not interactive, exits with a non-zero + cial parameters "@" and "*" as an error when performing + parameter expansion. If expansion is attempted on an + unset variable or parameter, the shell prints an error + message, and, if not interactive, exits with a non-zero status. --vv Print shell input lines as they are read. - --xx After expanding each _s_i_m_p_l_e _c_o_m_m_a_n_d, ffoorr command, ccaassee + --xx After expanding each _s_i_m_p_l_e _c_o_m_m_a_n_d, ffoorr command, ccaassee command, sseelleecctt command, or arithmetic ffoorr command, dis- - play the expanded value of PPSS44, followed by the command + play the expanded value of PPSS44, followed by the command and its expanded arguments or associated word list. - --BB The shell performs brace expansion (see BBrraaccee EExxppaannssiioonn + --BB The shell performs brace expansion (see BBrraaccee EExxppaannssiioonn above). This is on by default. - --CC If set, bbaasshh does not overwrite an existing file with - the >>, >>&&, and <<>> redirection operators. This may be + --CC If set, bbaasshh does not overwrite an existing file with + the >>, >>&&, and <<>> redirection operators. This may be overridden when creating output files by using the redi- rection operator >>|| instead of >>. --EE If set, any trap on EERRRR is inherited by shell functions, - command substitutions, and commands executed in a sub- - shell environment. The EERRRR trap is normally not inher- + command substitutions, and commands executed in a sub- + shell environment. The EERRRR trap is normally not inher- ited in such cases. --HH Enable !! style history substitution. This option is on by default when the shell is interactive. - --PP If set, the shell does not resolve symbolic links when - executing commands such as ccdd that change the current + --PP If set, the shell does not resolve symbolic links when + executing commands such as ccdd that change the current working directory. It uses the physical directory structure instead. By default, bbaasshh follows the logical - chain of directories when performing commands which + chain of directories when performing commands which change the current directory. - --TT If set, any traps on DDEEBBUUGG and RREETTUURRNN are inherited by - shell functions, command substitutions, and commands - executed in a subshell environment. The DDEEBBUUGG and - RREETTUURRNN traps are normally not inherited in such cases. - ---- If no arguments follow this option, then the positional + --TT If set, any traps on DDEEBBUUGG and RREETTUURRNN are inherited by + shell functions, command substitutions, and commands ex- + ecuted in a subshell environment. The DDEEBBUUGG and RREETTUURRNN + traps are normally not inherited in such cases. + ---- If no arguments follow this option, then the positional parameters are unset. Otherwise, the positional parame- - ters are set to the _a_r_gs, even if some of them begin + ters are set to the _a_r_gs, even if some of them begin with a --. - -- Signal the end of options, cause all remaining _a_r_gs to + -- Signal the end of options, cause all remaining _a_r_gs to be assigned to the positional parameters. The --xx and --vv options are turned off. If there are no _a_r_gs, the posi- tional parameters remain unchanged. - The options are off by default unless otherwise noted. Using + - rather than - causes these options to be turned off. The - options can also be specified as arguments to an invocation of - the shell. The current set of options may be found in $$--. The - return status is always true unless an invalid option is encoun- + The options are off by default unless otherwise noted. Using + + rather than - causes these options to be turned off. The op- + tions can also be specified as arguments to an invocation of the + shell. The current set of options may be found in $$--. The re- + turn status is always true unless an invalid option is encoun- tered. sshhiifftt [_n] - The positional parameters from _n+1 ... are renamed to $$11 ........ - Parameters represented by the numbers $$## down to $$##-_n+1 are - unset. _n must be a non-negative number less than or equal to - $$##. If _n is 0, no parameters are changed. If _n is not given, - it is assumed to be 1. If _n is greater than $$##, the positional - parameters are not changed. The return status is greater than - zero if _n is greater than $$## or less than zero; otherwise 0. + The positional parameters from _n+1 ... are renamed to $$11 ........ + Parameters represented by the numbers $$## down to $$##-_n+1 are un- + set. _n must be a non-negative number less than or equal to $$##. + If _n is 0, no parameters are changed. If _n is not given, it is + assumed to be 1. If _n is greater than $$##, the positional param- + eters are not changed. The return status is greater than zero + if _n is greater than $$## or less than zero; otherwise 0. sshhoopptt [--ppqqssuu] [--oo] [_o_p_t_n_a_m_e ...] - Toggle the values of settings controlling optional shell behav- - ior. The settings can be either those listed below, or, if the + Toggle the values of settings controlling optional shell behav- + ior. The settings can be either those listed below, or, if the --oo option is used, those available with the --oo option to the sseett builtin command. With no options, or with the --pp option, a list - of all settable options is displayed, with an indication of + of all settable options is displayed, with an indication of whether or not each is set; if _o_p_t_n_a_m_e_s are supplied, the output - is restricted to those options. The --pp option causes output to - be displayed in a form that may be reused as input. Other - options have the following meanings: + is restricted to those options. The --pp option causes output to + be displayed in a form that may be reused as input. Other op- + tions have the following meanings: --ss Enable (set) each _o_p_t_n_a_m_e. --uu Disable (unset) each _o_p_t_n_a_m_e. - --qq Suppresses normal output (quiet mode); the return status + --qq Suppresses normal output (quiet mode); the return status indicates whether the _o_p_t_n_a_m_e is set or unset. If multi- - ple _o_p_t_n_a_m_e arguments are given with --qq, the return sta- - tus is zero if all _o_p_t_n_a_m_e_s are enabled; non-zero other- + ple _o_p_t_n_a_m_e arguments are given with --qq, the return sta- + tus is zero if all _o_p_t_n_a_m_e_s are enabled; non-zero other- wise. - --oo Restricts the values of _o_p_t_n_a_m_e to be those defined for + --oo Restricts the values of _o_p_t_n_a_m_e to be those defined for the --oo option to the sseett builtin. - If either --ss or --uu is used with no _o_p_t_n_a_m_e arguments, sshhoopptt - shows only those options which are set or unset, respectively. - Unless otherwise noted, the sshhoopptt options are disabled (unset) + If either --ss or --uu is used with no _o_p_t_n_a_m_e arguments, sshhoopptt + shows only those options which are set or unset, respectively. + Unless otherwise noted, the sshhoopptt options are disabled (unset) by default. - The return status when listing options is zero if all _o_p_t_n_a_m_e_s - are enabled, non-zero otherwise. When setting or unsetting - options, the return status is zero unless an _o_p_t_n_a_m_e is not a + The return status when listing options is zero if all _o_p_t_n_a_m_e_s + are enabled, non-zero otherwise. When setting or unsetting op- + tions, the return status is zero unless an _o_p_t_n_a_m_e is not a valid shell option. The list of sshhoopptt options is: aassssoocc__eexxppaanndd__oonnccee - If set, the shell suppresses multiple evaluation of - associative array subscripts during arithmetic expres- - sion evaluation, while executing builtins that can per- - form variable assignments, and while executing builtins - that perform array dereferencing. - aauuttooccdd If set, a command name that is the name of a directory - is executed as if it were the argument to the ccdd com- + If set, the shell suppresses multiple evaluation of as- + sociative array subscripts during arithmetic expression + evaluation, while executing builtins that can perform + variable assignments, and while executing builtins that + perform array dereferencing. + aauuttooccdd If set, a command name that is the name of a directory + is executed as if it were the argument to the ccdd com- mand. This option is only used by interactive shells. ccddaabbllee__vvaarrss - If set, an argument to the ccdd builtin command that is - not a directory is assumed to be the name of a variable + If set, an argument to the ccdd builtin command that is + not a directory is assumed to be the name of a variable whose value is the directory to change to. ccddssppeellll If set, minor errors in the spelling of a directory com- - ponent in a ccdd command will be corrected. The errors + ponent in a ccdd command will be corrected. The errors checked for are transposed characters, a missing charac- - ter, and one character too many. If a correction is - found, the corrected filename is printed, and the com- - mand proceeds. This option is only used by interactive + ter, and one character too many. If a correction is + found, the corrected filename is printed, and the com- + mand proceeds. This option is only used by interactive shells. cchheecckkhhaasshh If set, bbaasshh checks that a command found in the hash ta- - ble exists before trying to execute it. If a hashed - command no longer exists, a normal path search is per- + ble exists before trying to execute it. If a hashed + command no longer exists, a normal path search is per- formed. cchheecckkjjoobbss If set, bbaasshh lists the status of any stopped and running - jobs before exiting an interactive shell. If any jobs + jobs before exiting an interactive shell. If any jobs are running, this causes the exit to be deferred until a - second exit is attempted without an intervening command - (see JJOOBB CCOONNTTRROOLL above). The shell always postpones - exiting if any jobs are stopped. + second exit is attempted without an intervening command + (see JJOOBB CCOONNTTRROOLL above). The shell always postpones ex- + iting if any jobs are stopped. cchheecckkwwiinnssiizzee - If set, bbaasshh checks the window size after each external - (non-builtin) command and, if necessary, updates the - values of LLIINNEESS and CCOOLLUUMMNNSS. This option is enabled by + If set, bbaasshh checks the window size after each external + (non-builtin) command and, if necessary, updates the + values of LLIINNEESS and CCOOLLUUMMNNSS. This option is enabled by default. - ccmmddhhiisstt If set, bbaasshh attempts to save all lines of a multiple- - line command in the same history entry. This allows - easy re-editing of multi-line commands. This option is - enabled by default, but only has an effect if command + ccmmddhhiisstt If set, bbaasshh attempts to save all lines of a multiple- + line command in the same history entry. This allows + easy re-editing of multi-line commands. This option is + enabled by default, but only has an effect if command history is enabled, as described above under HHIISSTTOORRYY. ccoommppaatt3311 - If set, bbaasshh changes its behavior to that of version 3.1 - with respect to quoted arguments to the [[[[ conditional - command's ==~~ operator and locale-specific string compar- - ison when using the [[[[ conditional command's << and >> - operators. Bash versions prior to bash-4.1 use ASCII - collation and _s_t_r_c_m_p(3); bash-4.1 and later use the cur- - rent locale's collation sequence and _s_t_r_c_o_l_l(3). ccoommppaatt3322 - If set, bbaasshh changes its behavior to that of version 3.2 - with respect to locale-specific string comparison when - using the [[[[ conditional command's << and >> operators - (see previous item) and the effect of interrupting a - command list. Bash versions 3.2 and earlier continue - with the next command in the list after one terminates - due to an interrupt. ccoommppaatt4400 - If set, bbaasshh changes its behavior to that of version 4.0 - with respect to locale-specific string comparison when - using the [[[[ conditional command's << and >> operators - (see description of ccoommppaatt3311) and the effect of inter- - rupting a command list. Bash versions 4.0 and later - interrupt the list as if the shell received the inter- - rupt; previous versions continue with the next command - in the list. ccoommppaatt4411 - If set, bbaasshh, when in _p_o_s_i_x _m_o_d_e, treats a single quote - in a double-quoted parameter expansion as a special - character. The single quotes must match (an even num- - ber) and the characters between the single quotes are - considered quoted. This is the behavior of posix mode - through version 4.1. The default bash behavior remains - as in previous versions. ccoommppaatt4422 - If set, bbaasshh does not process the replacement string in - the pattern substitution word expansion using quote - removal. ccoommppaatt4433 - If set, bbaasshh does not print a warning message if an - attempt is made to use a quoted compound array assign- - ment as an argument to ddeeccllaarree, makes word expansion - errors non-fatal errors that cause the current command - to fail (the default behavior is to make them fatal - errors that cause the shell to exit), and does not reset - the loop state when a shell function is executed (this - allows bbrreeaakk or ccoonnttiinnuuee in a shell function to affect - loops in the caller's context). ccoommppaatt4444 - If set, bbaasshh saves the positional parameters to - BASH_ARGV and BASH_ARGC before they are used, regardless - of whether or not extended debugging mode is enabled. + These control aspects of the shell's compatibility mode + (see SSHHEELLLL CCOOMMPPAATTIIBBIILLIITTYY MMOODDEE below). + ccoommpplleettee__ffuullllqquuoottee - If set, bbaasshh quotes all shell metacharacters in file- - names and directory names when performing completion. + If set, bbaasshh quotes all shell metacharacters in file- + names and directory names when performing completion. If not set, bbaasshh removes metacharacters such as the dol- - lar sign from the set of characters that will be quoted - in completed filenames when these metacharacters appear - in shell variable references in words to be completed. - This means that dollar signs in variable names that - expand to directories will not be quoted; however, any - dollar signs appearing in filenames will not be quoted, - either. This is active only when bash is using back- - slashes to quote completed filenames. This variable is - set by default, which is the default bash behavior in + lar sign from the set of characters that will be quoted + in completed filenames when these metacharacters appear + in shell variable references in words to be completed. + This means that dollar signs in variable names that ex- + pand to directories will not be quoted; however, any + dollar signs appearing in filenames will not be quoted, + either. This is active only when bash is using back- + slashes to quote completed filenames. This variable is + set by default, which is the default bash behavior in versions through 4.2. + ddiirreexxppaanndd - If set, bbaasshh replaces directory names with the results - of word expansion when performing filename completion. - This changes the contents of the readline editing buf- - fer. If not set, bbaasshh attempts to preserve what the + If set, bbaasshh replaces directory names with the results + of word expansion when performing filename completion. + This changes the contents of the readline editing buf- + fer. If not set, bbaasshh attempts to preserve what the user typed. + ddiirrssppeellll - If set, bbaasshh attempts spelling correction on directory - names during word completion if the directory name ini- + If set, bbaasshh attempts spelling correction on directory + names during word completion if the directory name ini- tially supplied does not exist. - ddoottgglloobb If set, bbaasshh includes filenames beginning with a `.' in - the results of pathname expansion. The filenames ````..'''' - and ````....'''' must always be matched explicitly, even if + + ddoottgglloobb If set, bbaasshh includes filenames beginning with a `.' in + the results of pathname expansion. The filenames ````..'''' + and ````....'''' must always be matched explicitly, even if ddoottgglloobb is set. + eexxeeccffaaiill If set, a non-interactive shell will not exit if it can- - not execute the file specified as an argument to the - eexxeecc builtin command. An interactive shell does not + not execute the file specified as an argument to the + eexxeecc builtin command. An interactive shell does not exit if eexxeecc fails. + eexxppaanndd__aalliiaasseess - If set, aliases are expanded as described above under + If set, aliases are expanded as described above under AALLIIAASSEESS. This option is enabled by default for interac- tive shells. + eexxttddeebbuugg - If set at shell invocation, arrange to execute the - debugger profile before the shell starts, identical to - the ----ddeebbuuggggeerr option. If set after invocation, behav- - ior intended for use by debuggers is enabled: + If set at shell invocation, or in a shell startup file, + arrange to execute the debugger profile before the shell + starts, identical to the ----ddeebbuuggggeerr option. If set af- + ter invocation, behavior intended for use by debuggers + is enabled: + 11.. The --FF option to the ddeeccllaarree builtin displays the source file name and line number corresponding to each function name supplied as an argument. + 22.. If the command run by the DDEEBBUUGG trap returns a non-zero value, the next command is skipped and not executed. + 33.. If the command run by the DDEEBBUUGG trap returns a value of 2, and the shell is executing in a sub- routine (a shell function or a shell script exe- cuted by the .. or ssoouurrccee builtins), the shell simulates a call to rreettuurrnn. + 44.. BBAASSHH__AARRGGCC and BBAASSHH__AARRGGVV are updated as described in their descriptions above. + 55.. Function tracing is enabled: command substitu- tion, shell functions, and subshells invoked with (( _c_o_m_m_a_n_d )) inherit the DDEEBBUUGG and RREETTUURRNN traps. + 66.. Error tracing is enabled: command substitution, shell functions, and subshells invoked with (( _c_o_m_m_a_n_d )) inherit the EERRRR trap. + eexxttgglloobb If set, the extended pattern matching features described above under PPaatthhnnaammee EExxppaannssiioonn are enabled. + eexxttqquuoottee If set, $$'_s_t_r_i_n_g' and $$"_s_t_r_i_n_g" quoting is performed within $${{_p_a_r_a_m_e_t_e_r}} expansions enclosed in double quotes. This option is enabled by default. + ffaaiillgglloobb If set, patterns which fail to match filenames during pathname expansion result in an expansion error. + ffoorrccee__ffiiggnnoorree If set, the suffixes specified by the FFIIGGNNOORREE shell variable cause words to be ignored when performing word completion even if the ignored words are the only possi- - ble completions. See SSHHEELLLL VVAARRIIAABBLLEESS above for a - description of FFIIGGNNOORREE. This option is enabled by - default. + ble completions. See SSHHEELLLL VVAARRIIAABBLLEESS above for a de- + scription of FFIIGGNNOORREE. This option is enabled by de- + fault. + gglloobbaasscciiiirraannggeess If set, range expressions used in pattern matching bracket expressions (see PPaatttteerrnn MMaattcchhiinngg above) behave as if in the traditional C locale when performing com- - parisons. That is, the current locale's collating - sequence is not taken into account, so bb will not col- - late between AA and BB, and upper-case and lower-case - ASCII characters will collate together. + parisons. That is, the current locale's collating se- + quence is not taken into account, so bb will not collate + between AA and BB, and upper-case and lower-case ASCII + characters will collate together. + gglloobbssttaarr If set, the pattern **** used in a pathname expansion con- text will match all files and zero or more directories and subdirectories. If the pattern is followed by a //, only directories and subdirectories match. + ggnnuu__eerrrrffmmtt If set, shell error messages are written in the standard GNU error message format. + hhiissttaappppeenndd If set, the history list is appended to the file named - by the value of the HHIISSTTFFIILLEE variable when the shell - exits, rather than overwriting the file. + by the value of the HHIISSTTFFIILLEE variable when the shell ex- + its, rather than overwriting the file. + hhiissttrreeeeddiitt If set, and rreeaaddlliinnee is being used, a user is given the opportunity to re-edit a failed history substitution. + hhiissttvveerriiffyy If set, and rreeaaddlliinnee is being used, the results of his- tory substitution are not immediately passed to the shell parser. Instead, the resulting line is loaded into the rreeaaddlliinnee editing buffer, allowing further modi- fication. + hhoossttccoommpplleettee If set, and rreeaaddlliinnee is being used, bbaasshh will attempt to perform hostname completion when a word containing a @@ is being completed (see CCoommpplleettiinngg under RREEAADDLLIINNEE above). This is enabled by default. + hhuuppoonneexxiitt If set, bbaasshh will send SSIIGGHHUUPP to all jobs when an inter- active login shell exits. + iinnhheerriitt__eerrrreexxiitt If set, command substitution inherits the value of the eerrrreexxiitt option, instead of unsetting it in the subshell environment. This option is enabled when _p_o_s_i_x _m_o_d_e is enabled. + iinntteerraaccttiivvee__ccoommmmeennttss If set, allow a word beginning with ## to cause that word and all remaining characters on that line to be ignored - in an interactive shell (see CCOOMMMMEENNTTSS above). This - option is enabled by default. + in an interactive shell (see CCOOMMMMEENNTTSS above). This op- + tion is enabled by default. + llaassttppiippee If set, and job control is not active, the shell runs the last command of a pipeline not executed in the back- ground in the current shell environment. + lliitthhiisstt If set, and the ccmmddhhiisstt option is enabled, multi-line commands are saved to the history with embedded newlines rather than using semicolon separators where possible. + llooccaallvvaarr__iinnhheerriitt If set, local variables inherit the value and attributes of a variable of the same name that exists at a previous - scope before any new value is assigned. The nameref - attribute is not inherited. + scope before any new value is assigned. The nameref at- + tribute is not inherited. + llooccaallvvaarr__uunnsseett If set, calling uunnsseett on local variables in previous function scopes marks them so subsequent lookups find them unset until that function returns. This is identi- cal to the behavior of unsetting local variables at the current function scope. + llooggiinn__sshheellll The shell sets this option if it is started as a login shell (see IINNVVOOCCAATTIIOONN above). The value may not be changed. + mmaaiillwwaarrnn If set, and a file that bbaasshh is checking for mail has been accessed since the last time it was checked, the message ``The mail in _m_a_i_l_f_i_l_e has been read'' is dis- played. + nnoo__eemmppttyy__ccmmdd__ccoommpplleettiioonn - If set, and rreeaaddlliinnee is being used, bbaasshh will not - attempt to search the PPAATTHH for possible completions when + If set, and rreeaaddlliinnee is being used, bbaasshh will not at- + tempt to search the PPAATTHH for possible completions when completion is attempted on an empty line. + nnooccaasseegglloobb If set, bbaasshh matches filenames in a case-insensitive fashion when performing pathname expansion (see PPaatthhnnaammee EExxppaannssiioonn above). + nnooccaasseemmaattcchh If set, bbaasshh matches patterns in a case-insensitive fashion when performing matching while executing ccaassee or [[[[ conditional commands, when performing pattern substi- tution word expansions, or when filtering possible com- pletions as part of programmable completion. + nnuullllgglloobb If set, bbaasshh allows patterns which match no files (see PPaatthhnnaammee EExxppaannssiioonn above) to expand to a null string, rather than themselves. + pprrooggccoommpp If set, the programmable completion facilities (see PPrroo-- ggrraammmmaabbllee CCoommpplleettiioonn above) are enabled. This option is enabled by default. + pprrooggccoommpp__aalliiaass If set, and programmable completion is enabled, bbaasshh treats a command name that doesn't have any completions as a possible alias and attempts alias expansion. If it - has an alias, bbaasshh attempts programmable completion - using the command word resulting from the expanded - alias. + has an alias, bbaasshh attempts programmable completion us- + ing the command word resulting from the expanded alias. + pprroommppttvvaarrss If set, prompt strings undergo parameter expansion, com- - mand substitution, arithmetic expansion, and quote - removal after being expanded as described in PPRROOMMPPTTIINNGG + mand substitution, arithmetic expansion, and quote re- + moval after being expanded as described in PPRROOMMPPTTIINNGG above. This option is enabled by default. + rreessttrriicctteedd__sshheellll - The shell sets this option if it is started in - restricted mode (see RREESSTTRRIICCTTEEDD SSHHEELLLL below). The value - may not be changed. This is not reset when the startup - files are executed, allowing the startup files to dis- + The shell sets this option if it is started in re- + stricted mode (see RREESSTTRRIICCTTEEDD SSHHEELLLL below). The value + may not be changed. This is not reset when the startup + files are executed, allowing the startup files to dis- cover whether or not a shell is restricted. + sshhiifftt__vveerrbboossee - If set, the sshhiifftt builtin prints an error message when + If set, the sshhiifftt builtin prints an error message when the shift count exceeds the number of positional parame- ters. + ssoouurrcceeppaatthh If set, the ssoouurrccee (..) builtin uses the value of PPAATTHH to - find the directory containing the file supplied as an + find the directory containing the file supplied as an argument. This option is enabled by default. + xxppgg__eecchhoo - If set, the eecchhoo builtin expands backslash-escape - sequences by default. + If set, the eecchhoo builtin expands backslash-escape se- + quences by default. ssuussppeenndd [--ff] - Suspend the execution of this shell until it receives a SSIIGGCCOONNTT + Suspend the execution of this shell until it receives a SSIIGGCCOONNTT signal. A login shell cannot be suspended; the --ff option can be used to override this and force the suspension. The return sta- - tus is 0 unless the shell is a login shell and --ff is not sup- + tus is 0 unless the shell is a login shell and --ff is not sup- plied, or if job control is not enabled. tteesstt _e_x_p_r [[ _e_x_p_r ]] Return a status of 0 (true) or 1 (false) depending on the evalu- ation of the conditional expression _e_x_p_r. Each operator and op- - erand must be a separate argument. Expressions are composed of - the primaries described above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS. - tteesstt does not accept any options, nor does it accept and ignore + erand must be a separate argument. Expressions are composed of + the primaries described above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS. + tteesstt does not accept any options, nor does it accept and ignore an argument of ---- as signifying the end of options. - Expressions may be combined using the following operators, - listed in decreasing order of precedence. The evaluation - depends on the number of arguments; see below. Operator prece- + Expressions may be combined using the following operators, + listed in decreasing order of precedence. The evaluation de- + pends on the number of arguments; see below. Operator prece- dence is used when there are five or more arguments. !! _e_x_p_r True if _e_x_p_r is false. (( _e_x_p_r )) - Returns the value of _e_x_p_r. This may be used to override + Returns the value of _e_x_p_r. This may be used to override the normal precedence of operators. _e_x_p_r_1 -aa _e_x_p_r_2 True if both _e_x_p_r_1 and _e_x_p_r_2 are true. @@ -5836,134 +5923,135 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS null. 2 arguments If the first argument is !!, the expression is true if and - only if the second argument is null. If the first argu- - ment is one of the unary conditional operators listed - above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS, the expression is + only if the second argument is null. If the first argu- + ment is one of the unary conditional operators listed + above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS, the expression is true if the unary test is true. If the first argument is not a valid unary conditional operator, the expression is false. 3 arguments The following conditions are applied in the order listed. - If the second argument is one of the binary conditional + If the second argument is one of the binary conditional operators listed above under CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS, the result of the expression is the result of the binary test - using the first and third arguments as operands. The --aa - and --oo operators are considered binary operators when - there are three arguments. If the first argument is !!, - the value is the negation of the two-argument test using + using the first and third arguments as operands. The --aa + and --oo operators are considered binary operators when + there are three arguments. If the first argument is !!, + the value is the negation of the two-argument test using the second and third arguments. If the first argument is exactly (( and the third argument is exactly )), the result - is the one-argument test of the second argument. Other- + is the one-argument test of the second argument. Other- wise, the expression is false. 4 arguments If the first argument is !!, the result is the negation of - the three-argument expression composed of the remaining + the three-argument expression composed of the remaining arguments. Otherwise, the expression is parsed and eval- - uated according to precedence using the rules listed + uated according to precedence using the rules listed above. 5 or more arguments - The expression is parsed and evaluated according to + The expression is parsed and evaluated according to precedence using the rules listed above. - When used with tteesstt or [[, the << and >> operators sort lexico- + When used with tteesstt or [[, the << and >> operators sort lexico- graphically using ASCII ordering. - ttiimmeess Print the accumulated user and system times for the shell and + ttiimmeess Print the accumulated user and system times for the shell and for processes run from the shell. The return status is 0. ttrraapp [--llpp] [[_a_r_g] _s_i_g_s_p_e_c ...] - The command _a_r_g is to be read and executed when the shell - receives signal(s) _s_i_g_s_p_e_c. If _a_r_g is absent (and there is a - single _s_i_g_s_p_e_c) or --, each specified signal is reset to its - original disposition (the value it had upon entrance to the - shell). If _a_r_g is the null string the signal specified by each - _s_i_g_s_p_e_c is ignored by the shell and by the commands it invokes. - If _a_r_g is not present and --pp has been supplied, then the trap - commands associated with each _s_i_g_s_p_e_c are displayed. If no - arguments are supplied or if only --pp is given, ttrraapp prints the - list of commands associated with each signal. The --ll option - causes the shell to print a list of signal names and their cor- - responding numbers. Each _s_i_g_s_p_e_c is either a signal name - defined in <_s_i_g_n_a_l_._h>, or a signal number. Signal names are - case insensitive and the SSIIGG prefix is optional. - - If a _s_i_g_s_p_e_c is EEXXIITT (0) the command _a_r_g is executed on exit - from the shell. If a _s_i_g_s_p_e_c is DDEEBBUUGG, the command _a_r_g is exe- - cuted before every _s_i_m_p_l_e _c_o_m_m_a_n_d, _f_o_r command, _c_a_s_e command, - _s_e_l_e_c_t command, every arithmetic _f_o_r command, and before the - first command executes in a shell function (see SSHHEELLLL GGRRAAMMMMAARR - above). Refer to the description of the eexxttddeebbuugg option to the + The command _a_r_g is to be read and executed when the shell re- + ceives signal(s) _s_i_g_s_p_e_c. If _a_r_g is absent (and there is a sin- + gle _s_i_g_s_p_e_c) or --, each specified signal is reset to its origi- + nal disposition (the value it had upon entrance to the shell). + If _a_r_g is the null string the signal specified by each _s_i_g_s_p_e_c + is ignored by the shell and by the commands it invokes. If _a_r_g + is not present and --pp has been supplied, then the trap commands + associated with each _s_i_g_s_p_e_c are displayed. If no arguments are + supplied or if only --pp is given, ttrraapp prints the list of com- + mands associated with each signal. The --ll option causes the + shell to print a list of signal names and their corresponding + numbers. Each _s_i_g_s_p_e_c is either a signal name defined in <_s_i_g_- + _n_a_l_._h>, or a signal number. Signal names are case insensitive + and the SSIIGG prefix is optional. + + If a _s_i_g_s_p_e_c is EEXXIITT (0) the command _a_r_g is executed on exit + from the shell. If a _s_i_g_s_p_e_c is DDEEBBUUGG, the command _a_r_g is exe- + cuted before every _s_i_m_p_l_e _c_o_m_m_a_n_d, _f_o_r command, _c_a_s_e command, + _s_e_l_e_c_t command, every arithmetic _f_o_r command, and before the + first command executes in a shell function (see SSHHEELLLL GGRRAAMMMMAARR + above). Refer to the description of the eexxttddeebbuugg option to the sshhoopptt builtin for details of its effect on the DDEEBBUUGG trap. If a _s_i_g_s_p_e_c is RREETTUURRNN, the command _a_r_g is executed each time a shell function or a script executed with the .. or ssoouurrccee builtins fin- ishes executing. - If a _s_i_g_s_p_e_c is EERRRR, the command _a_r_g is executed whenever a + If a _s_i_g_s_p_e_c is EERRRR, the command _a_r_g is executed whenever a pipeline (which may consist of a single simple command), a list, or a compound command returns a non-zero exit status, subject to - the following conditions. The EERRRR trap is not executed if the + the following conditions. The EERRRR trap is not executed if the failed command is part of the command list immediately following - a wwhhiillee or uunnttiill keyword, part of the test in an _i_f statement, + a wwhhiillee or uunnttiill keyword, part of the test in an _i_f statement, part of a command executed in a &&&& or |||| list except the command - following the final &&&& or ||||, any command in a pipeline but the - last, or if the command's return value is being inverted using - !!. These are the same conditions obeyed by the eerrrreexxiitt (--ee) - option. + following the final &&&& or ||||, any command in a pipeline but the + last, or if the command's return value is being inverted using + !!. These are the same conditions obeyed by the eerrrreexxiitt (--ee) op- + tion. - Signals ignored upon entry to the shell cannot be trapped or - reset. Trapped signals that are not being ignored are reset to + Signals ignored upon entry to the shell cannot be trapped or re- + set. Trapped signals that are not being ignored are reset to their original values in a subshell or subshell environment when - one is created. The return status is false if any _s_i_g_s_p_e_c is + one is created. The return status is false if any _s_i_g_s_p_e_c is invalid; otherwise ttrraapp returns true. ttyyppee [--aaffttppPP] _n_a_m_e [_n_a_m_e ...] - With no options, indicate how each _n_a_m_e would be interpreted if + With no options, indicate how each _n_a_m_e would be interpreted if used as a command name. If the --tt option is used, ttyyppee prints a - string which is one of _a_l_i_a_s, _k_e_y_w_o_r_d, _f_u_n_c_t_i_o_n, _b_u_i_l_t_i_n, or - _f_i_l_e if _n_a_m_e is an alias, shell reserved word, function, - builtin, or disk file, respectively. If the _n_a_m_e is not found, - then nothing is printed, and an exit status of false is - returned. If the --pp option is used, ttyyppee either returns the - name of the disk file that would be executed if _n_a_m_e were speci- - fied as a command name, or nothing if ``type -t name'' would not - return _f_i_l_e. The --PP option forces a PPAATTHH search for each _n_a_m_e, + string which is one of _a_l_i_a_s, _k_e_y_w_o_r_d, _f_u_n_c_t_i_o_n, _b_u_i_l_t_i_n, or + _f_i_l_e if _n_a_m_e is an alias, shell reserved word, function, + builtin, or disk file, respectively. If the _n_a_m_e is not found, + then nothing is printed, and an exit status of false is re- + turned. If the --pp option is used, ttyyppee either returns the name + of the disk file that would be executed if _n_a_m_e were specified + as a command name, or nothing if ``type -t name'' would not re- + turn _f_i_l_e. The --PP option forces a PPAATTHH search for each _n_a_m_e, even if ``type -t name'' would not return _f_i_l_e. If a command is hashed, --pp and --PP print the hashed value, which is not necessar- - ily the file that appears first in PPAATTHH. If the --aa option is - used, ttyyppee prints all of the places that contain an executable + ily the file that appears first in PPAATTHH. If the --aa option is + used, ttyyppee prints all of the places that contain an executable named _n_a_m_e. This includes aliases and functions, if and only if the --pp option is not also used. The table of hashed commands is - not consulted when using --aa. The --ff option suppresses shell + not consulted when using --aa. The --ff option suppresses shell function lookup, as with the ccoommmmaanndd builtin. ttyyppee returns true if all of the arguments are found, false if any are not found. - uulliimmiitt [--HHSSaabbccddeeffiikkllmmnnppqqrrssttuuvvxxPPTT [_l_i_m_i_t]] - Provides control over the resources available to the shell and - to processes started by it, on systems that allow such control. + uulliimmiitt [--HHSS] --aa + uulliimmiitt [--HHSS] [--bbccddeeffiikkllmmnnppqqrrssttuuvvxxPPRRTT [_l_i_m_i_t]] + Provides control over the resources available to the shell and + to processes started by it, on systems that allow such control. The --HH and --SS options specify that the hard or soft limit is set - for the given resource. A hard limit cannot be increased by a - non-root user once it is set; a soft limit may be increased up - to the value of the hard limit. If neither --HH nor --SS is speci- + for the given resource. A hard limit cannot be increased by a + non-root user once it is set; a soft limit may be increased up + to the value of the hard limit. If neither --HH nor --SS is speci- fied, both the soft and hard limits are set. The value of _l_i_m_i_t can be a number in the unit specified for the resource or one of the special values hhaarrdd, ssoofftt, or uunnlliimmiitteedd, which stand for the - current hard limit, the current soft limit, and no limit, - respectively. If _l_i_m_i_t is omitted, the current value of the - soft limit of the resource is printed, unless the --HH option is - given. When more than one resource is specified, the limit name - and unit are printed before the value. Other options are inter- - preted as follows: - --aa All current limits are reported + current hard limit, the current soft limit, and no limit, re- + spectively. If _l_i_m_i_t is omitted, the current value of the soft + limit of the resource is printed, unless the --HH option is given. + When more than one resource is specified, the limit name and + unit, if appropriate, are printed before the value. Other op- + tions are interpreted as follows: + --aa All current limits are reported; no limits are set --bb The maximum socket buffer size --cc The maximum size of core files created --dd The maximum size of a process's data segment --ee The maximum scheduling priority ("nice") - --ff The maximum size of files written by the shell and its + --ff The maximum size of files written by the shell and its children --ii The maximum number of pending signals --kk The maximum number of kqueues that may be allocated --ll The maximum size that may be locked into memory - --mm The maximum resident set size (many systems do not honor + --mm The maximum resident set size (many systems do not honor this limit) --nn The maximum number of open file descriptors (most systems do not allow this value to be set) @@ -5972,71 +6060,213 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --rr The maximum real-time scheduling priority --ss The maximum stack size --tt The maximum amount of cpu time in seconds - --uu The maximum number of processes available to a single + --uu The maximum number of processes available to a single user - --vv The maximum amount of virtual memory available to the + --vv The maximum amount of virtual memory available to the shell and, on some systems, to its children --xx The maximum number of file locks --PP The maximum number of pseudoterminals + --RR The maximum time a real-time process can run before + blocking, in microseconds --TT The maximum number of threads If _l_i_m_i_t is given, and the --aa option is not used, _l_i_m_i_t is the new value of the specified resource. If no option is given, then --ff is assumed. Values are in 1024-byte increments, except - for --tt, which is in seconds; --pp, which is in units of 512-byte - blocks; --PP, --TT, --bb, --kk, --nn, and --uu, which are unscaled values; - and, when in posix mode, --cc and --ff, which are in 512-byte incre- - ments. The return status is 0 unless an invalid option or argu- - ment is supplied, or an error occurs while setting a new limit. + for --tt, which is in seconds; --RR, which is in microseconds; --pp, + which is in units of 512-byte blocks; --PP, --TT, --bb, --kk, --nn, and + --uu, which are unscaled values; and, when in posix mode, --cc and + --ff, which are in 512-byte increments. The return status is 0 + unless an invalid option or argument is supplied, or an error + occurs while setting a new limit. uummaasskk [--pp] [--SS] [_m_o_d_e] The user file-creation mask is set to _m_o_d_e. If _m_o_d_e begins with - a digit, it is interpreted as an octal number; otherwise it is - interpreted as a symbolic mode mask similar to that accepted by - _c_h_m_o_d(1). If _m_o_d_e is omitted, the current value of the mask is - printed. The --SS option causes the mask to be printed in sym- - bolic form; the default output is an octal number. If the --pp + a digit, it is interpreted as an octal number; otherwise it is + interpreted as a symbolic mode mask similar to that accepted by + _c_h_m_o_d(1). If _m_o_d_e is omitted, the current value of the mask is + printed. The --SS option causes the mask to be printed in sym- + bolic form; the default output is an octal number. If the --pp option is supplied, and _m_o_d_e is omitted, the output is in a form that may be reused as input. The return status is 0 if the mode - was successfully changed or if no _m_o_d_e argument was supplied, + was successfully changed or if no _m_o_d_e argument was supplied, and false otherwise. uunnaalliiaass [-aa] [_n_a_m_e ...] - Remove each _n_a_m_e from the list of defined aliases. If --aa is - supplied, all alias definitions are removed. The return value + Remove each _n_a_m_e from the list of defined aliases. If --aa is + supplied, all alias definitions are removed. The return value is true unless a supplied _n_a_m_e is not a defined alias. uunnsseett [-ffvv] [-nn] [_n_a_m_e ...] - For each _n_a_m_e, remove the corresponding variable or function. + For each _n_a_m_e, remove the corresponding variable or function. If the --vv option is given, each _n_a_m_e refers to a shell variable, - and that variable is removed. Read-only variables may not be - unset. If --ff is specified, each _n_a_m_e refers to a shell func- - tion, and the function definition is removed. If the --nn option - is supplied, and _n_a_m_e is a variable with the _n_a_m_e_r_e_f attribute, - _n_a_m_e will be unset rather than the variable it references. --nn - has no effect if the --ff option is supplied. If no options are - supplied, each _n_a_m_e refers to a variable; if there is no vari- - able by that name, any function with that name is unset. Each - unset variable or function is removed from the environment - passed to subsequent commands. If any of CCOOMMPP__WWOORRDDBBRREEAAKKSS, RRAANN-- - DDOOMM, SSEECCOONNDDSS, LLIINNEENNOO, HHIISSTTCCMMDD, FFUUNNCCNNAAMMEE, GGRROOUUPPSS, or DDIIRRSSTTAACCKK are + and that variable is removed. Read-only variables may not be + unset. If --ff is specified, each _n_a_m_e refers to a shell func- + tion, and the function definition is removed. If the --nn option + is supplied, and _n_a_m_e is a variable with the _n_a_m_e_r_e_f attribute, + _n_a_m_e will be unset rather than the variable it references. --nn + has no effect if the --ff option is supplied. If no options are + supplied, each _n_a_m_e refers to a variable; if there is no vari- + able by that name, a function with that name, if any, is unset. + Each unset variable or function is removed from the environment + passed to subsequent commands. If any of BBAASSHH__AALLIIAASSEESS, + BBAASSHH__AARRGGVV00, BBAASSHH__CCMMDDSS, BBAASSHH__CCOOMMMMAANNDD, BBAASSHH__SSUUBBSSHHEELLLL, BBAASSHHPPIIDD, + CCOOMMPP__WWOORRDDBBRREEAAKKSS, DDIIRRSSTTAACCKK, EEPPOOCCHHRREEAALLTTIIMMEE, EEPPOOCCHHSSEECCOONNDDSS, FFUUNNCC-- + NNAAMMEE, GGRROOUUPPSS, HHIISSTTCCMMDD, LLIINNEENNOO, RRAANNDDOOMM, SSEECCOONNDDSS, or SSRRAANNDDOOMM are unset, they lose their special properties, even if they are sub- sequently reset. The exit status is true unless a _n_a_m_e is read- only. - wwaaiitt [--ffnn] [_i_d _._._.] + wwaaiitt [--ffnn] [--pp _v_a_r_n_a_m_e] [_i_d _._._.] Wait for each specified child process and return its termination - status. Each _i_d may be a process ID or a job specification; if - a job spec is given, all processes in that job's pipeline are - waited for. If _i_d is not given, all currently active child pro- - cesses are waited for, and the return status is zero. If the --nn - option is supplied, wwaaiitt waits for any job to terminate and - returns its exit status. If the --ff option is supplied, and job - control is enabled, wwaaiitt forces _i_d to terminate before returning - its status, instead of returning when it changes status. If _i_d - specifies a non-existent process or job, the return status is - 127. Otherwise, the return status is the exit status of the - last process or job waited for. + status. Each _i_d may be a process ID or a job specification; if + a job spec is given, all processes in that job's pipeline are + waited for. If _i_d is not given, wwaaiitt waits for all running + background jobs and the last-executed process substitution, if + its process id is the same as $$!!, and the return status is zero. + If the --nn option is supplied, wwaaiitt waits for a single job from + the list of _i_ds or, if no _i_ds are supplied, any job, to complete + and returns its exit status. If none of the supplied arguments + is a child of the shell, or if no arguments are supplied and the + shell has no unwaited-for children, the exit status is 127. If + the --pp option is supplied, the process or job identifier of the + job for which the exit status is returned is assigned to the + variable _v_a_r_n_a_m_e named by the option argument. The variable + will be unset initially, before any assignment. This is useful + only when the --nn option is supplied. Supplying the --ff option, + when job control is enabled, forces wwaaiitt to wait for _i_d to ter- + minate before returning its status, instead of returning when it + changes status. If _i_d specifies a non-existent process or job, + the return status is 127. Otherwise, the return status is the + exit status of the last process or job waited for. + +SSHHEELLLL CCOOMMPPAATTIIBBIILLIITTYY MMOODDEE + Bash-4.0 introduced the concept of a `shell compatibility level', spec- + ified as a set of options to the shopt builtin ccoommppaatt3311, ccoommppaatt3322, ccoomm-- + ppaatt4400, ccoommppaatt4411, and so on). There is only one current compatibility + level -- each option is mutually exclusive. The compatibility level is + intended to allow users to select behavior from previous versions that + is incompatible with newer versions while they migrate scripts to use + current features and behavior. It's intended to be a temporary solu- + tion. + + This section does not mention behavior that is standard for a particu- + lar version (e.g., setting ccoommppaatt3322 means that quoting the rhs of the + regexp matching operator quotes special regexp characters in the word, + which is default behavior in bash-3.2 and above). + + If a user enables, say, ccoommppaatt3322, it may affect the behavior of other + compatibility levels up to and including the current compatibility + level. The idea is that each compatibility level controls behavior + that changed in that version of bbaasshh, but that behavior may have been + present in earlier versions. For instance, the change to use locale- + based comparisons with the [[[[ command came in bash-4.1, and earlier + versions used ASCII-based comparisons, so enabling ccoommppaatt3322 will enable + ASCII-based comparisons as well. That granularity may not be suffi- + cient for all uses, and as a result users should employ compatibility + levels carefully. Read the documentation for a particular feature to + find out the current behavior. + + Bash-4.3 introduced a new shell variable: BBAASSHH__CCOOMMPPAATT. The value as- + signed to this variable (a decimal version number like 4.2, or an inte- + ger corresponding to the ccoommppaatt_N_N option, like 42) determines the com- + patibility level. + + Starting with bash-4.4, Bash has begun deprecating older compatibility + levels. Eventually, the options will be removed in favor of BBAASSHH__CCOOMM-- + PPAATT. + + Bash-5.0 is the final version for which there will be an individual + shopt option for the previous version. Users should use BBAASSHH__CCOOMMPPAATT on + bash-5.0 and later versions. + + The following table describes the behavior changes controlled by each + compatibility level setting. The ccoommppaatt_N_N tag is used as shorthand for + setting the compatibility level to _N_N using one of the following mecha- + nisms. For versions prior to bash-5.0, the compatibility level may be + set using the corresponding ccoommppaatt_N_N shopt option. For bash-4.3 and + later versions, the BBAASSHH__CCOOMMPPAATT variable is preferred, and it is re- + quired for bash-5.1 and later versions. + + ccoommppaatt3311 + +o quoting the rhs of the [[[[ command's regexp matching oper- + ator (=~) has no special effect + + ccoommppaatt3322 + +o interrupting a command list such as "a ; b ; c" causes + the execution of the next command in the list (in + bash-4.0 and later versions, the shell acts as if it re- + ceived the interrupt, so interrupting one command in a + list aborts the execution of the entire list) + + ccoommppaatt4400 + +o the << and >> operators to the [[[[ command do not consider + the current locale when comparing strings; they use ASCII + ordering. Bash versions prior to bash-4.1 use ASCII col- + lation and _s_t_r_c_m_p(3); bash-4.1 and later use the current + locale's collation sequence and _s_t_r_c_o_l_l(3). + + ccoommppaatt4411 + +o in _p_o_s_i_x mode, ttiimmee may be followed by options and still + be recognized as a reserved word (this is POSIX interpre- + tation 267) + +o in _p_o_s_i_x mode, the parser requires that an even number of + single quotes occur in the _w_o_r_d portion of a double- + quoted parameter expansion and treats them specially, so + that characters within the single quotes are considered + quoted (this is POSIX interpretation 221) + + ccoommppaatt4422 + +o the replacement string in double-quoted pattern substitu- + tion does not undergo quote removal, as it does in ver- + sions after bash-4.2 + +o in posix mode, single quotes are considered special when + expanding the _w_o_r_d portion of a double-quoted parameter + expansion and can be used to quote a closing brace or + other special character (this is part of POSIX interpre- + tation 221); in later versions, single quotes are not + special within double-quoted word expansions + + ccoommppaatt4433 + +o the shell does not print a warning message if an attempt + is made to use a quoted compound assignment as an argu- + ment to declare (declare -a foo='(1 2)'). Later versions + warn that this usage is deprecated + +o word expansion errors are considered non-fatal errors + that cause the current command to fail, even in posix + mode (the default behavior is to make them fatal errors + that cause the shell to exit) + +o when executing a shell function, the loop state + (while/until/etc.) is not reset, so bbrreeaakk or ccoonnttiinnuuee in + that function will break or continue loops in the calling + context. Bash-4.4 and later reset the loop state to pre- + vent this + + ccoommppaatt4444 + +o the shell sets up the values used by BBAASSHH__AARRGGVV and + BBAASSHH__AARRGGCC so they can expand to the shell's positional + parameters even if extended debugging mode is not enabled + +o a subshell inherits loops from its parent context, so + bbrreeaakk or ccoonnttiinnuuee will cause the subshell to exit. + Bash-5.0 and later reset the loop state to prevent the + exit + +o variable assignments preceding builtins like eexxppoorrtt and + rreeaaddoonnllyy that set attributes continue to affect variables + with the same name in the calling environment even if the + shell is not in posix mode + + ccoommppaatt5500 + +o Bash-5.1 changed the way $$RRAANNDDOOMM is generated to intro- + duce slightly more randomness. If the shell compatibility + level is set to 50 or lower, it reverts to the method + from bash-5.0 and previous versions, so seeding the ran- + dom number generator by assigning a value to RRAANNDDOOMM will + produce the same sequence as in bash-5.0 + +o If the command hash table is empty, bash versions prior + to bash-5.1 printed an informational message to that ef- + fect, even when producing output that can be reused as + input. Bash-5.1 suppresses that message when the --ll op- + tion is supplied. RREESSTTRRIICCTTEEDD SSHHEELLLL If bbaasshh is started with the name rrbbaasshh, or the --rr option is supplied at @@ -6047,13 +6277,17 @@ RREESSTTRRIICCTTEEDD SSHHEELLLL +o changing directories with ccdd - +o setting or unsetting the values of SSHHEELLLL, PPAATTHH, EENNVV, or BBAASSHH__EENNVV + +o setting or unsetting the values of SSHHEELLLL, PPAATTHH, HHIISSTTFFIILLEE, EENNVV, + or BBAASSHH__EENNVV +o specifying command names containing // - +o specifying a filename containing a // as an argument to the .. + +o specifying a filename containing a // as an argument to the .. builtin command + +o specifying a filename containing a slash as an argument to the + hhiissttoorryy builtin command + +o specifying a filename containing a slash as an argument to the --pp option to the hhaasshh builtin command @@ -6168,4 +6402,4 @@ BBUUGGSS -GNU Bash 5.0 2018 December 7 BASH(1) +GNU Bash 5.1 2020 October 29 BASH(1) |