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| author | Chet Ramey <chet.ramey@case.edu> | 2019-01-07 09:27:52 -0500 |
|---|---|---|
| committer | Chet Ramey <chet.ramey@case.edu> | 2019-01-07 09:27:52 -0500 |
| commit | d233b485e83c3a784b803fb894280773f16f2deb (patch) | |
| tree | 16d51f3ccca2d4ad2d8f2da564d68ca848de595b /doc/bash.0 | |
| parent | 64447609994bfddeef1061948022c074093e9a9f (diff) | |
| download | bash-d233b485e83c3a784b803fb894280773f16f2deb.tar.gz | |
bash-5.0 distribution sources and documentationbash-5.0
Diffstat (limited to 'doc/bash.0')
| -rw-r--r-- | doc/bash.0 | 3521 |
1 files changed, 1877 insertions, 1644 deletions
@@ -9,7 +9,7 @@ SSYYNNOOPPSSIISS bbaasshh [options] [command_string | file] CCOOPPYYRRIIGGHHTT - Bash is Copyright (C) 1989-2016 by the Free Software Foundation, Inc. + Bash is Copyright (C) 1989-2018 by the Free Software Foundation, Inc. DDEESSCCRRIIPPTTIIOONN BBaasshh is an sshh-compatible command language interpreter that executes @@ -22,9 +22,9 @@ DDEESSCCRRIIPPTTIIOONN OOPPTTIIOONNSS All of the single-character shell options documented in the description - of the sseett builtin command can be used as options when the shell is - invoked. In addition, bbaasshh interprets the following options when it is - invoked: + 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: --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- @@ -41,67 +41,68 @@ OOPPTTIIOONNSS --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. - --DD A list of all double-quoted strings preceded by $$ is printed - on the standard output. These are the strings that are sub- + set when invoking an interactive shell or when reading input + through a pipe. + --DD A list of all double-quoted strings preceded by $$ is printed + on the standard output. These are the strings that are sub- 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 + 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. ----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 + tialization file _~_/_._b_a_s_h_r_c if the shell is interactive (see IINNVVOOCCAATTIIOONN 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 + 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). ----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 + _~_/_._b_a_s_h_r_c if the shell is interactive. This option is on by default 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 @@ -111,115 +112,115 @@ 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 + executed, 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 + 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 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 + 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- + 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 + 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 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 + 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. - 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 + 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. DDEEFFIINNIITTIIOONNSS - The following definitions are used throughout the rest of this docu- + The following definitions are used throughout the rest of this docu- ment. bbllaannkk A space or tab. - wwoorrdd A sequence of characters considered as a single unit by the + wwoorrdd A sequence of characters considered as a single unit by the shell. Also known as a ttookkeenn. - nnaammee A _w_o_r_d consisting only of alphanumeric characters and under- - scores, and beginning with an alphabetic character or an under- + nnaammee A _w_o_r_d consisting only of alphanumeric characters and under- + scores, and beginning with an alphabetic character or an under- score. Also referred to as an iiddeennttiiffiieerr. mmeettaacchhaarraacctteerr - A character that, when unquoted, separates words. One of the + A character that, when unquoted, separates words. One of the following: || && ;; (( )) << >> ssppaaccee ttaabb nneewwlliinnee ccoonnttrrooll ooppeerraattoorr @@ -230,63 +231,66 @@ 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 + first word of a simple command (see SSHHEELLLL GGRRAAMMMMAARR below) or the third word of a ccaassee or ffoorr command: - !! 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 + and is passed as argument zero. The remaining words are passed as arguments 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). + 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 @@ -301,107 +305,108 @@ SSHHEELLLL GGRRAAMMMMAARR 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. 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 executed. - - AND and OR lists are sequences of one or more pipelines separated by - the &&&& and |||| control operators, respectively. AND and OR lists are + 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- + cuted. + + 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 - of zero. + _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 + (_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 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 + 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"". [[[[ _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 an extended regular expres- - sion and matched accordingly (as 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 conditional - expression's return value is 2. If the nnooccaasseemmaattcchh shell option - is enabled, the match is performed without regard to the 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 carefully, - since normal quoting characters lose their meanings between - 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 subexpressions - 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 expression. - 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, + 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 + 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 + option is enabled, the match is performed without regard to the + 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, + 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 + of the string matching the _nth parenthesized subexpression. + + Expressions may be combined using the following operators, listed in decreasing order of precedence: (( _e_x_p_r_e_s_s_i_o_n )) - Returns the value of _e_x_p_r_e_s_s_i_o_n. This may be used to + Returns the value of _e_x_p_r_e_s_s_i_o_n. This may be used to override the normal precedence of operators. !! _e_x_p_r_e_s_s_i_o_n True if _e_x_p_r_e_s_s_i_o_n is false. @@ -411,110 +416,111 @@ SSHHEELLLL GGRRAAMMMMAARR True if either _e_x_p_r_e_s_s_i_o_n_1 or _e_x_p_r_e_s_s_i_o_n_2 is true. The &&&& and |||| operators do not evaluate _e_x_p_r_e_s_s_i_o_n_2 if the value - of _e_x_p_r_e_s_s_i_o_n_1 is sufficient to determine the return value of + of _e_x_p_r_e_s_s_i_o_n_1 is sufficient to determine the return value of the entire conditional expression. ffoorr _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 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 + 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 - is the exit status of the last command that executes. If the + 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. ffoorr (( _e_x_p_r_1 ; _e_x_p_r_2 ; _e_x_p_r_3 )) ; ddoo _l_i_s_t ; ddoonnee First, the arithmetic expression _e_x_p_r_1 is evaluated according to - the rules described below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. The - arithmetic expression _e_x_p_r_2 is then evaluated repeatedly until - it evaluates to zero. Each time _e_x_p_r_2 evaluates to a non-zero - value, _l_i_s_t is executed and the arithmetic expression _e_x_p_r_3 is - evaluated. If any expression is omitted, it behaves as if it + the rules described below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. The + arithmetic expression _e_x_p_r_2 is then evaluated repeatedly until + it evaluates to zero. Each time _e_x_p_r_2 evaluates to a non-zero + value, _l_i_s_t is executed and the arithmetic expression _e_x_p_r_3 is + evaluated. If any expression is omitted, it behaves as if it evaluates to 1. The return value is the exit status of the last command in _l_i_s_t that is executed, or false if any of the expres- sions is invalid. 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- + 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 + 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, + 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 - each _p_a_t_t_e_r_n in turn, using the same matching rules as for path- - name expansion (see PPaatthhnnaammee EExxppaannssiioonn below). The _w_o_r_d is - expanded using tilde expansion, parameter and variable expan- - sion, arithmetic expansion, command substitution, process sub- - stitution and quote removal. Each _p_a_t_t_e_r_n examined is expanded - using tilde expansion, parameter and variable expansion, arith- - metic expansion, command substitution, and process substitution. - If the nnooccaasseemmaattcchh shell option is enabled, the match is per- - formed without regard to the case of alphabetic characters. - When a match is found, the corresponding _l_i_s_t is executed. If - the ;;;; operator is used, no subsequent matches are attempted - after the first pattern match. Using ;;&& in place of ;;;; causes - execution to continue with the _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 successful 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. + each _p_a_t_t_e_r_n in turn, using the matching rules described under + PPaatttteerrnn MMaattcchhiinngg below. The _w_o_r_d is expanded using tilde expan- + sion, parameter and variable expansion, arithmetic expansion, + command substitution, process substitution and quote removal. + Each _p_a_t_t_e_r_n examined is expanded using tilde expansion, parame- + ter and variable expansion, arithmetic expansion, command sub- + stitution, and process substitution. If the nnooccaasseemmaattcchh shell + option is enabled, the match is performed without regard to the + case of alphabetic characters. When a match is found, the cor- + responding _l_i_s_t is executed. If the ;;;; operator is used, no + subsequent matches are attempted after the first pattern match. + Using ;;&& in place of ;;;; causes execution to continue with the + _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. 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 + 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. CCoopprroocceesssseess A _c_o_p_r_o_c_e_s_s is a shell command preceded by the ccoopprroocc reserved word. A - coprocess is executed asynchronously in a subshell, as if the command - had been terminated with the && control operator, with a two-way pipe + coprocess is executed asynchronously in a subshell, as if the command + had been terminated with the && control operator, with a two-way pipe established between the executing shell and the coprocess. The format for a coprocess is: 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 + 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 + 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. The file + 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 @@ -617,7 +623,7 @@ QQUUOOTTIINNGG \\"" double quote \\?? question mark \\_n_n_n the eight-bit character whose value is the octal value - _n_n_n (one to three digits) + _n_n_n (one to three octal digits) \\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 @@ -730,76 +736,86 @@ PPAARRAAMMEETTEERRSS is the first character of the value of the IIFFSS variable. If IIFFSS 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. When + @@ 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 $$@@ expand to + "$$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 + -- 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 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 command, after expansion. Also set to - the full pathname used to invoke each command executed and - placed in the environment exported to that command. When check- - ing mail, this parameter holds the name of the mail file cur- - rently being checked. + __ 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 + 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 $$$$ under certain circumstances, such as subshells - that do not require bbaasshh to be re-initialized. + Expands to the process ID of the current bbaasshh process. This + differs from $$$$ 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) + 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 vari- + 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- rent bbaasshh execution call stack. The final parameter of the last @@ -808,7 +824,15 @@ PPAARRAAMMEETTEERRSS 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) + below). 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 + 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 + 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 @@ -918,71 +942,82 @@ PPAARRAAMMEETTEERRSS able will not change the current directory. If DDIIRRSSTTAACCKK is unset, it loses its special properties, even if it is subse- quently reset. - EEUUIIDD Expands to the effective user ID of the current user, initial- + 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 + point value with micro-second granularity. Assignments to + EEPPOOCCHHRREEAALLTTIIMMEE are ignored. If EEPPOOCCHHRREEAALLTTIIMMEE is unset, it loses + its special properties, even if it is subsequently reset. + EEPPOOCCHHSSEECCOONNDDSS + Each time this parameter is referenced, it expands to the number + of seconds since the Unix Epoch (see _t_i_m_e(3)). Assignments to + EEPPOOCCHHSSEECCOONNDDSS are ignored. If EEPPOOCCHHSSEECCOONNDDSS is unset, it loses + its special properties, even if it is subsequently reset. + EEUUIIDD Expands to the effective user ID of the current user, initial- ized at shell startup. This variable is readonly. FFUUNNCCNNAAMMEE - An array variable containing the names of all shell functions + An array variable containing the names of all shell functions currently in the execution call stack. The element with index 0 is the name of any currently-executing shell function. The bot- - 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 + 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. - 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 - $${{BBAASSHH__SSOOUURRCCEE[[_$_i_+_1]]}} at line number $${{BBAASSHH__LLIINNEENNOO[[_$_i]]}}. The + 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__SSOOUURRCCEE[[_$_i_+_1]]}} at line number $${{BBAASSHH__LLIINNEENNOO[[_$_i]]}}. The ccaalllleerr builtin displays the current call stack using this infor- mation. - GGRROOUUPPSS An array variable containing the list of groups of which the + GGRROOUUPPSS An array variable containing the list of groups of which the current user is a member. Assignments to GGRROOUUPPSS have no effect. - If GGRROOUUPPSS is unset, it loses its special properties, even if it + If GGRROOUUPPSS is unset, it loses its special properties, even if it 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, + command. If HHIISSTTCCMMDD is unset, 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 + it loses its special properties, even if it is subsequently reset. RREEAADDLLIINNEE__LLIINNEE The contents of the rreeaaddlliinnee line buffer, for use with "bind -x" @@ -990,197 +1025,202 @@ PPAARRAAMMEETTEERRSS RREEAADDLLIINNEE__PPOOIINNTT The position of the insertion point in the rreeaaddlliinnee line buffer, for use with "bind -x" (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). - RREEPPLLYY Set to the line of input read by the rreeaadd builtin command when + RREEPPLLYY Set to the line of input read by the rreeaadd builtin command when no arguments are supplied. SSEECCOONNDDSS - Each time this parameter is referenced, the number of seconds - 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. + Each time this parameter is referenced, the number of seconds + 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. 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 + A colon-separated list of enabled shell options. Each word in + the list is a valid argument for the --oo option to the sseett builtin command (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). The options - appearing in SSHHEELLLLOOPPTTSS are those reported as _o_n by sseett --oo. 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 SSHHEELLLLOOPPTTSS are those reported as _o_n by sseett --oo. 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. SSHHLLVVLL Incremented by one each time an instance of bbaasshh is started. 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 + The following variables are used by the shell. In some cases, bbaasshh assigns 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 + 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 + 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. BBAASSHH__EENNVV - If this parameter is set when bbaasshh is executing a shell script, - its value is interpreted as a filename containing commands to + If this parameter is set when bbaasshh is executing a shell script, + its value is interpreted as a filename containing commands to initialize the shell, as in _~_/_._b_a_s_h_r_c. The value of BBAASSHH__EENNVV is - subjected to parameter expansion, command substitution, and - arithmetic expansion before being interpreted as a filename. + subjected to parameter expansion, command substitution, and + arithmetic expansion before being interpreted as a filename. 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 - 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 + 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 + 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 + 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 ".:~:/usr". CCHHIILLDD__MMAAXX - Set the number of exited child status values for the shell to - remember. Bash will not allow this value to be decreased below - a POSIX-mandated minimum, and there is a maximum value (cur- - rently 8192) that this may not exceed. The minimum value is + Set the number of exited child status values for the shell to + remember. Bash will not allow this value to be decreased below + a POSIX-mandated minimum, and there is a maximum value (cur- + rently 8192) that this may not exceed. The minimum value is system-dependent. CCOOLLUUMMNNSS - Used by the sseelleecctt compound command to determine the terminal - width when printing selection lists. Automatically set if the - cchheecckkwwiinnssiizzee option is enabled or in an interactive shell upon + Used by the sseelleecctt compound command to determine the terminal + width when printing selection lists. Automatically set if the + cchheecckkwwiinnssiizzee option is enabled or in an interactive shell upon receipt of a SSIIGGWWIINNCCHH. 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 + generated by a shell function invoked by the programmable com- + pletion facility (see PPrrooggrraammmmaabbllee CCoommpplleettiioonn below). Each array 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 + 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 POSIX - mode. + EENNVV Similar to BBAASSHH__EENNVV; used when the 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 - using PPAATTHH. Files whose full pathnames match one of these pat- - terns are not considered executable files for the purposes of + A colon-separated list of shell patterns (see PPaatttteerrnn MMaattcchhiinngg) + defining the list of filenames to be ignored by command search + using PPAATTHH. Files whose full pathnames match one of these pat- + terns are not considered executable files for the purposes of completion and command execution via PPAATTHH lookup. This does not affect the behavior of the [[, tteesstt, and [[[[ commands. Full path- - names in the command hash table are not subject to EEXXEECCIIGGNNOORREE. - Use this variable to ignore shared library files that have the - executable bit set, but are not executable files. The pattern + names in the command hash table are not subject to EEXXEECCIIGGNNOORREE. + Use this variable to ignore shared library files that have the + executable bit set, but are not executable files. The pattern matching honors the setting of the eexxttgglloobb shell option. FFCCEEDDIITT The default editor for the ffcc builtin command. FFIIGGNNOORREE - A colon-separated list of suffixes to ignore when performing + A colon-separated list of suffixes to ignore when performing filename completion (see RREEAADDLLIINNEE below). A filename whose suf- - fix matches one of the entries in FFIIGGNNOORREE is excluded from the + fix matches one of the entries in FFIIGGNNOORREE is excluded from the list of matched filenames. A sample value is ".o:~". FFUUNNCCNNEESSTT - If set to a numeric value greater than 0, defines a maximum - function nesting level. Function invocations that exceed this + If set to a numeric value greater than 0, defines a maximum + function nesting level. Function invocations that exceed this nesting level will cause the current command to abort. GGLLOOBBIIGGNNOORREE - A colon-separated list of patterns defining the set of filenames - to be ignored by pathname expansion. If a filename matched by a - pathname expansion pattern also matches one of the patterns in - GGLLOOBBIIGGNNOORREE, it is removed from the list of matches. + A colon-separated list of patterns defining the set of file + names to be ignored by pathname expansion. If a file name + matched by a pathname expansion pattern also matches one of the + 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 in the history list. A value of _i_g_n_o_r_e_d_u_p_s causes lines + 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 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 of _e_r_a_s_e_d_u_p_s causes all previous lines matching the current line - to be removed from the history list before that line is saved. - Any value not in the above list is ignored. If HHIISSTTCCOONNTTRROOLL is - unset, or does not include a valid value, all lines read by the + to be removed from the history list before that line is saved. + Any value not in the above list is ignored. If HHIISSTTCCOONNTTRROOLL is + unset, or does not include a valid value, all lines read by the shell parser are saved on the history list, subject to the value - of HHIISSTTIIGGNNOORREE. The second and subsequent lines of a multi-line - compound command are not tested, and are added to the history + of HHIISSTTIIGGNNOORREE. 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 HHIISSTTCCOONNTTRROOLL. HHIISSTTFFIILLEE The name of the file in which command history is saved (see HHIISS-- - TTOORRYY below). The default value is _~_/_._b_a_s_h___h_i_s_t_o_r_y. If unset, + TTOORRYY below). The default value is _~_/_._b_a_s_h___h_i_s_t_o_r_y. If unset, the command history is not saved when a shell exits. HHIISSTTFFIILLEESSIIZZEE The maximum number of lines contained in the history file. When - this variable is assigned a value, the history file is trun- - cated, if necessary, to contain no more than that number of - lines by removing the oldest entries. The history file is also - truncated to this size after writing it when a shell exits. If - the value is 0, the history file is truncated to zero size. - Non-numeric values and numeric values less than zero inhibit - truncation. The shell sets the default value to the value of + this variable is assigned a value, the history file is trun- + cated, if necessary, to contain no more than that number of + lines by removing the oldest entries. The history file is also + truncated to this size after writing it when a shell exits. If + the value is 0, the history file is truncated to zero size. + Non-numeric values and numeric values less than zero inhibit + truncation. The shell sets the default value to the value of 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 + 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 + 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 + history regardless of the value of HHIISSTTIIGGNNOORREE. The pattern matching 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 + The number of commands to remember in the command history (see + HHIISSTTOORRYY below). If the value is 0, commands are not saved in the history list. Numeric values less than zero result in every - command being saved on the history list (there is no limit). - The shell sets the default value to 500 after reading any + command being saved on the history list (there is no limit). + The shell sets the default value to 500 after reading any startup files. HHIISSTTTTIIMMEEFFOORRMMAATT - If this variable is set and not null, its value is used as a + If this variable is set and not null, its value is used as a format string for _s_t_r_f_t_i_m_e(3) to print the time stamp associated - with each history entry displayed by the hhiissttoorryy builtin. If - this variable is set, time stamps are written to the history - file so they may be preserved across shell sessions. This uses - the history comment character to distinguish timestamps from + with each history entry displayed by the hhiissttoorryy builtin. If + this variable is set, time stamps are written to the history + file so they may be preserved across shell sessions. This uses + the history comment character to distinguish timestamps from other history lines. HHOOMMEE The home directory of the current user; the default argument for the ccdd builtin command. The value of this variable is also used when performing tilde expansion. HHOOSSTTFFIILLEE - Contains the name of a file in the same format as _/_e_t_c_/_h_o_s_t_s + 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 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- + 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 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 + after expansion and to split lines into words with the rreeaadd builtin command. The default value is ``<space><tab><new- line>''. IIGGNNOORREEEEOOFF Controls the action of an interactive shell on receipt of an EEOOFF character as the sole input. If set, the value is the number of - consecutive EEOOFF characters which must be typed as the first - characters on an input line before bbaasshh exits. If the variable - exists but does not have a numeric value, or has no value, the - default value is 10. If it does not exist, EEOOFF signifies the + consecutive EEOOFF characters which must be typed as the first + characters on an input line before bbaasshh exits. If the variable + exists but does not have a numeric value, or has no value, the + 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 + The filename for the rreeaaddlliinnee startup file, overriding the default 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 + buffer and may disable line editing, depending on the value of + TTEERRMM. LLAANNGG Used to determine the locale category for any category not specifically selected with a variable starting with LLCC__. LLCC__AALLLL This variable overrides the value of LLAANNGG and any other LLCC__ @@ -1246,39 +1286,40 @@ PPAARRAAMMEETTEERRSS 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. + 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. 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 PPSS44 is replicated mul- - tiple times, as necessary, to indicate multiple levels of indi- - rection. The default is ``++ ''. + 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 + able. 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. @@ -1286,77 +1327,77 @@ 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 + TTMMOOUUTT If set to a value greater than zero, TTMMOOUUTT is treated as the default 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. @@ -1364,96 +1405,103 @@ 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 + 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 + 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. - 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- - 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 + 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- + 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 last element. - Any element of an array may be referenced using ${_n_a_m_e[_s_u_b_s_c_r_i_p_t]}. + Any element of an array may be referenced using ${_n_a_m_e[_s_u_b_s_c_r_i_p_t]}. The braces are required to avoid conflicts with pathname expansion. If - _s_u_b_s_c_r_i_p_t is @@ or **, the word expands to all members of _n_a_m_e. These - subscripts differ only when the word appears within double quotes. If + _s_u_b_s_c_r_i_p_t is @@ or **, the word expands to all members of _n_a_m_e. These + subscripts differ only when the word appears within double quotes. If the word is double-quoted, ${_n_a_m_e[*]} expands to a single word with the - value of each array member separated by the first character of the IIFFSS + 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 + 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. Referencing an array variable without a subscript is equivalent to ref- - erencing the array with a subscript of 0. Any reference to a variable + erencing the array with a subscript of 0. Any reference to a variable using a valid subscript is legal, and bbaasshh will create an array if nec- essary. - An array variable is considered set if a subscript has been assigned a + An array variable is considered set if a subscript has been assigned a value. The null string is a valid value. - It is possible to obtain the keys (indices) of an array as well as the - values. ${!!_n_a_m_e[_@]} and ${!!_n_a_m_e[_*]} expand to the indices assigned in + It is possible to obtain the keys (indices) of an array as well as the + values. ${!!_n_a_m_e[_@]} and ${!!_n_a_m_e[_*]} expand to the indices assigned in 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. Negative subscripts to - indexed arrays are interpreted as described above. Care must be taken - to avoid unwanted side effects caused by pathname expansion. 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 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 - builtin accepts a --aa option to assign a list of words read from the + 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. + + 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. + + 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 + 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. EEXXPPAANNSSIIOONN Expansion is performed on the command line after it has been split into - words. There are seven kinds of expansion performed: _b_r_a_c_e _e_x_p_a_n_s_i_o_n, - _t_i_l_d_e _e_x_p_a_n_s_i_o_n, _p_a_r_a_m_e_t_e_r _a_n_d _v_a_r_i_a_b_l_e _e_x_p_a_n_s_i_o_n, _c_o_m_m_a_n_d _s_u_b_s_t_i_t_u_- + words. There are seven kinds of expansion performed: _b_r_a_c_e _e_x_p_a_n_s_i_o_n, + _t_i_l_d_e _e_x_p_a_n_s_i_o_n, _p_a_r_a_m_e_t_e_r _a_n_d _v_a_r_i_a_b_l_e _e_x_p_a_n_s_i_o_n, _c_o_m_m_a_n_d _s_u_b_s_t_i_t_u_- _t_i_o_n, _a_r_i_t_h_m_e_t_i_c _e_x_p_a_n_s_i_o_n, _w_o_r_d _s_p_l_i_t_t_i_n_g, and _p_a_t_h_n_a_m_e _e_x_p_a_n_s_i_o_n. The order of expansions is: brace expansion; tilde expansion, parameter - and variable expansion, arithmetic expansion, and command substitution - (done in a left-to-right fashion); word splitting; and pathname expan- + and variable expansion, arithmetic expansion, and command substitution + (done in a left-to-right fashion); word splitting; and pathname expan- sion. On systems that can support it, there is an additional expansion avail- - able: _p_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n. This is performed at the same time as - tilde, parameter, variable, and arithmetic expansion and command sub- + able: _p_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n. This is performed at the same time as + tilde, parameter, variable, and arithmetic expansion and command sub- stitution. - After these expansions are performed, quote characters present in the - original word are removed unless they have been quoted themselves + After these expansions are performed, quote characters present in the + 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 change - 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[[@@]]}}" as explained above (see PPAARRAAMMEETTEERRSS). + 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, $$** and + $${{_n_a_m_e[[**]]}} as explained above (see PPAARRAAMMEETTEERRSS). BBrraaccee EExxppaannssiioonn _B_r_a_c_e _e_x_p_a_n_s_i_o_n is a mechanism by which arbitrary strings may be gener- @@ -1492,7 +1540,8 @@ EEXXPPAANNSSIIOONN expression. 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 $${{ is not considered eligible for brace expansion. + sion, the string $${{ is not considered eligible for brace expansion, and + inhibits brace expansion until the closing }}. This construct is typically used as shorthand when the common prefix of the strings to be generated is longer than in the above example: @@ -1501,36 +1550,36 @@ EEXXPPAANNSSIIOONN or chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}} - Brace expansion introduces a slight incompatibility with historical - versions of sshh. sshh does not treat opening or closing braces specially - when they appear as part of a word, and preserves them in the output. - BBaasshh removes braces from words as a consequence of brace expansion. - For example, a word entered to sshh as _f_i_l_e_{_1_,_2_} appears identically in - the output. The same word is output as _f_i_l_e_1 _f_i_l_e_2 after expansion by - bbaasshh. If strict compatibility with sshh is desired, start bbaasshh with the + Brace expansion introduces a slight incompatibility with historical + versions of sshh. sshh does not treat opening or closing braces specially + when they appear as part of a word, and preserves them in the output. + BBaasshh removes braces from words as a consequence of brace expansion. + For example, a word entered to sshh as _f_i_l_e_{_1_,_2_} appears identically in + the output. The same word is output as _f_i_l_e_1 _f_i_l_e_2 after expansion by + bbaasshh. If strict compatibility with sshh is desired, start bbaasshh with the ++BB option or disable brace expansion with the ++BB option to the sseett com- mand (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). TTiillddee EExxppaannssiioonn - If a word begins with an unquoted tilde character (`~~'), all of the - characters preceding the first unquoted slash (or all characters, if - there is no unquoted slash) are considered a _t_i_l_d_e_-_p_r_e_f_i_x. If none of - the characters in the tilde-prefix are quoted, the characters in the - tilde-prefix following the tilde are treated as a possible _l_o_g_i_n _n_a_m_e. - If this login name is the null string, the tilde is replaced with the - value of the shell parameter HHOOMMEE. If HHOOMMEE is unset, the home direc- - tory of the user executing the shell is substituted instead. Other- - wise, the tilde-prefix is replaced with the home directory associated + If a word begins with an unquoted tilde character (`~~'), all of the + characters preceding the first unquoted slash (or all characters, if + there is no unquoted slash) are considered a _t_i_l_d_e_-_p_r_e_f_i_x. If none of + the characters in the tilde-prefix are quoted, the characters in the + tilde-prefix following the tilde are treated as a possible _l_o_g_i_n _n_a_m_e. + If this login name is the null string, the tilde is replaced with the + value of the shell parameter HHOOMMEE. If HHOOMMEE is unset, the home direc- + tory of the user executing the shell is substituted instead. Other- + 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 + 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 - 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 + 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 with the corresponding element from the directory stack, as it would be displayed by the ddiirrss builtin invoked with the tilde-prefix as an argu- - ment. If the characters following the tilde in the tilde-prefix con- + ment. If the characters following the tilde in the tilde-prefix con- sist of a number without a leading `+' or `-', `+' is assumed. If the login name is invalid, or the tilde expansion fails, the word is @@ -1538,10 +1587,15 @@ 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 + also performed. Consequently, one may use filenames with tildes in + assignments to PPAATTHH, MMAAIILLPPAATTHH, and CCDDPPAATTHH, and the shell assigns the expanded value. + Bash also performs tilde expansion on words satisfying the conditions + of variable assignments (as described above under PPAARRAAMMEETTEERRSS) when they + appear as arguments to simple commands. Bash does not do this, except + for the _d_e_c_l_a_r_a_t_i_o_n commands listed above, when in _p_o_s_i_x _m_o_d_e. + PPaarraammeetteerr EExxppaannssiioonn The `$$' character introduces parameter expansion, command substitution, or arithmetic expansion. The parameter name or symbol to be expanded @@ -1563,16 +1617,18 @@ EEXXPPAANNSSIIOONN (AArrrraayyss). 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 variable indirec- - tion. BBaasshh uses the value of the variable formed from the rest of - _p_a_r_a_m_e_t_e_r as the name of the variable; this variable is then expanded - and that value is used in the rest of the substitution, rather than the - value of _p_a_r_a_m_e_t_e_r itself. This is known as _i_n_d_i_r_e_c_t _e_x_p_a_n_s_i_o_n. If - _p_a_r_a_m_e_t_e_r is a nameref, this expands to the name of the variable refer- - enced by _p_a_r_a_m_e_t_e_r instead of performing the complete indirect expan- - sion. The exceptions to this are the expansions of ${!!_p_r_e_f_i_x**} and - ${!!_n_a_m_e[_@]} described below. The exclamation point must immediately - follow the left brace in order to introduce indirection. + _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 + 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 + 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 + must immediately follow the left brace in order to introduce indirec- + tion. In each of the cases below, _w_o_r_d is subject to tilde expansion, parame- ter expansion, command substitution, and arithmetic expansion. @@ -1673,100 +1729,105 @@ EEXXPPAANNSSIIOONN ${_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. If the pattern matches - the beginning of the value of _p_a_r_a_m_e_t_e_r, then the result of the + 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. + + ${_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 + 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 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. 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 pattern (the ``%%%%'' case) deleted. If _p_a_r_a_m_e_t_e_r is @@ - or **, the pattern removal operation is applied to each posi- - tional 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 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 + 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. 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 begin- - ning 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 // fol- - lowing _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 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 substitution operation is - applied to each member of the array in turn, and the expansion - is the resultant list. + _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 **, + 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, + 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- + 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- + 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 + 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 + 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 - $$''......'' quoting mechansim. + 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 + $$''......'' quoting mechanism. PP The expansion is a string that is the result of expanding the value of _p_a_r_a_m_e_t_e_r as if it were a prompt string (see PPRROOMMPPTTIINNGG below). - AA The expansion is a string in the form of an assignment - statement or ddeeccllaarree command that, if evaluated, will + AA The expansion is a string in the form of an assignment + statement or ddeeccllaarree command that, if evaluated, will recreate _p_a_r_a_m_e_t_e_r with its attributes and value. - aa The expansion is a string consisting of flag values rep- + aa The expansion is a string consisting of flag values rep- resenting _p_a_r_a_m_e_t_e_r's attributes. - If _p_a_r_a_m_e_t_e_r is @@ or **, the operation is applied to each posi- - tional parameter in turn, and the expansion is the resultant - list. If _p_a_r_a_m_e_t_e_r is an array variable subscripted with @@ or - **, the case modification operation is applied to each member of - the array in turn, and the expansion is the resultant list. + If _p_a_r_a_m_e_t_e_r is @@ or **, the operation is applied to each posi- + tional parameter in turn, and the expansion is the resultant + list. If _p_a_r_a_m_e_t_e_r is an array variable subscripted with @@ or + **, the operation is applied to each member of the array in turn, + and the expansion is the resultant list. - The result of the expansion is subject to word splitting and + The result of the expansion is subject to word splitting and pathname expansion as described below. CCoommmmaanndd SSuubbssttiittuuttiioonn @@ -1780,174 +1841,178 @@ EEXXPPAANNSSIIOONN BBaasshh performs the expansion by executing _c_o_m_m_a_n_d in a subshell environ- ment and replacing the command substitution with the standard output of the command, with any trailing newlines deleted. Embedded newlines are - not deleted, but they may be removed during word splitting. The com- - mand substitution $$((ccaatt _f_i_l_e)) can be replaced by the equivalent but + not deleted, but they may be removed during word splitting. The com- + mand substitution $$((ccaatt _f_i_l_e)) can be replaced by the equivalent but faster $$((<< _f_i_l_e)). - When the old-style backquote form of substitution is used, backslash - retains its literal meaning except when followed by $$, ``, or \\. The + When the old-style backquote form of substitution is used, backslash + retains its literal meaning except when followed by $$, ``, or \\. The first backquote not preceded by a backslash terminates the command sub- - stitution. When using the $(_c_o_m_m_a_n_d) form, all characters between the + stitution. When using the $(_c_o_m_m_a_n_d) form, all characters between the parentheses make up the command; none are treated specially. Command substitutions may be nested. To nest when using the backquoted form, escape the inner backquotes with backslashes. - If the substitution appears within double quotes, word splitting and + If the substitution appears within double quotes, word splitting and pathname expansion are not performed on the results. AArriitthhmmeettiicc EExxppaannssiioonn - Arithmetic expansion allows the evaluation of an arithmetic expression - and the substitution of the result. The format for arithmetic expan- + Arithmetic expansion allows the evaluation of an arithmetic expression + and the substitution of the result. The format for arithmetic expan- sion is: $$((((_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 + 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- - mand substitution, and quote removal. The result is treated as the - arithmetic expression to be evaluated. Arithmetic expansions may be + mand substitution, and quote removal. The result is treated as the + arithmetic expression to be evaluated. Arithmetic expansions may be nested. - The evaluation is performed according to the rules listed below under + The evaluation is performed according to the rules listed below under AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN. If _e_x_p_r_e_s_s_i_o_n is invalid, bbaasshh prints a message indicating failure and no substitution occurs. PPrroocceessss SSuubbssttiittuuttiioonn - _P_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n allows a process's input or output to be referred - to using a filename. It takes the form of <<((_l_i_s_t)) or >>((_l_i_s_t)). The - process _l_i_s_t is run asynchronously, and its input or output appears as + _P_r_o_c_e_s_s _s_u_b_s_t_i_t_u_t_i_o_n allows a process's input or output to be referred + to using a filename. It takes the form of <<((_l_i_s_t)) or >>((_l_i_s_t)). The + process _l_i_s_t is run asynchronously, and its input or output appears as a filename. This filename is passed as an argument to the current com- - mand as the result of the expansion. If the >>((_l_i_s_t)) form is used, - writing to the file will provide input for _l_i_s_t. If the <<((_l_i_s_t)) form - is used, the file passed as an argument should be read to obtain the + mand as the result of the expansion. If the >>((_l_i_s_t)) form is used, + writing to the file will provide input for _l_i_s_t. If the <<((_l_i_s_t)) form + is used, the file passed as an argument should be read to obtain the output of _l_i_s_t. Process substitution is supported on systems that sup- port named pipes (_F_I_F_O_s) or the //ddeevv//ffdd method of naming open files. - When available, process substitution is performed simultaneously with - parameter and variable expansion, command substitution, and arithmetic + When available, process substitution is performed simultaneously with + parameter and variable expansion, command substitution, and arithmetic expansion. WWoorrdd SSpplliittttiinngg - The shell scans the results of parameter expansion, command substitu- - tion, and arithmetic expansion that did not occur within double quotes + The shell scans the results of parameter expansion, command substitu- + tion, and arithmetic expansion that did not occur within double quotes for _w_o_r_d _s_p_l_i_t_t_i_n_g. - The shell treats each character of IIFFSS as a delimiter, and splits the - results of the other expansions into words using these characters as - field terminators. If IIFFSS is unset, or its value is exactly - <<ssppaaccee>><<ttaabb>><<nneewwlliinnee>>, the default, then sequences of <<ssppaaccee>>, <<ttaabb>>, - and <<nneewwlliinnee>> at the beginning and end of the results of the previous - expansions are ignored, and any sequence of IIFFSS characters not at the - beginning or end serves to delimit words. If IIFFSS has a value other - than the default, then sequences of the whitespace characters ssppaaccee, - ttaabb, and nneewwlliinnee are ignored at the beginning and end of the word, as - long as the whitespace character is in the value of IIFFSS (an IIFFSS white- - space character). Any character in IIFFSS that is not IIFFSS whitespace, + The shell treats each character of IIFFSS as a delimiter, and splits the + results of the other expansions into words using these characters as + field terminators. If IIFFSS is unset, or its value is exactly + <<ssppaaccee>><<ttaabb>><<nneewwlliinnee>>, the default, then sequences of <<ssppaaccee>>, <<ttaabb>>, + and <<nneewwlliinnee>> at the beginning and end of the results of the previous + expansions are ignored, and any sequence of IIFFSS characters not at the + beginning or end serves to delimit words. If IIFFSS has a value other + than the default, then sequences of the whitespace characters ssppaaccee, + ttaabb, and nneewwlliinnee are ignored at the beginning and end of the word, as + long as the whitespace character is in the value of IIFFSS (an IIFFSS white- + space character). Any character in IIFFSS that is not IIFFSS whitespace, along with any adjacent IIFFSS whitespace characters, delimits a field. A - sequence of IIFFSS whitespace characters is also treated as a delimiter. + sequence of IIFFSS whitespace characters is also treated as a delimiter. If the value of IIFFSS is null, no word splitting occurs. - Explicit null arguments ("""" or '''') are retained and passed to commands + 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'' + 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. 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 + 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. When matching a pathname, the slash char- - acter must always be matched explicitly. In other cases, the ````..'''' - character is not treated specially. See the description of sshhoopptt below - under SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS for a description of the nnooccaasseegglloobb, nnuullll-- - gglloobb, 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 filename - that also matches one of the patterns in GGLLOOBBIIGGNNOORREE is removed from the - list of matches. If the nnooccaasseegglloobb option is set, the matching against - the patterns in GGLLOOBBIIGGNNOORREE is performed without regard to case. The - filenames ````..'''' and ````....'''' are always ignored when GGLLOOBBIIGGNNOORREE is set - and not null. However, setting GGLLOOBBIIGGNNOORREE to a non-null value has the - effect of enabling the ddoottgglloobb shell option, so all other filenames - beginning with a ````..'''' will match. To get the old behavior of ignor- - ing filenames beginning with a ````..'''', make ````..**'''' one of the patterns - in GGLLOOBBIIGGNNOORREE. The ddoottgglloobb option is disabled when GGLLOOBBIIGGNNOORREE is - unset. The pattern matching honors the setting of the eexxttgglloobb shell + 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. + + 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 + name that also matches one of the patterns in GGLLOOBBIIGGNNOORREE is removed + from the list of matches. If the nnooccaasseegglloobb option is set, the match- + ing against the patterns in GGLLOOBBIIGGNNOORREE is performed without regard to + case. The filenames ````..'''' and ````....'''' are always ignored when GGLLOOBBIIGG-- + NNOORREE is set and not null. However, setting GGLLOOBBIIGGNNOORREE to a non-null + value has the effect of enabling the ddoottgglloobb shell option, so all other + filenames beginning with a ````..'''' will match. To get the old behavior + of ignoring filenames beginning with a ````..'''', make ````..**'''' one of the + patterns in GGLLOOBBIIGGNNOORREE. The ddoottgglloobb option is disabled when GGLLOOBBIIGGNNOORREE + is unset. The pattern matching honors the setting of the eexxttgglloobb shell option. PPaatttteerrnn MMaattcchhiinngg Any character that appears in a pattern, other than the special pattern - characters described below, matches itself. The NUL character may not - occur in a pattern. A backslash escapes the following character; the - escaping backslash is discarded when matching. The special pattern + characters described below, matches itself. The NUL character may not + occur in a pattern. A backslash escapes the following character; the + escaping backslash is discarded when matching. The special pattern characters must be quoted if they are to be matched literally. The special pattern characters have the following meanings: - ** 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 - adjacent **s will match only directories and subdirecto- + ** 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 + 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 + [[......]] 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 + 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 - [[aabbccdd]], set value of the LLCC__AALLLL shell variable to CC, or - enable the gglloobbaasscciiiirraannggeess shell option. A -- may be + tion 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 the set. A ]] may be matched by including it as the first character in the set. - Within [[ and ]], _c_h_a_r_a_c_t_e_r _c_l_a_s_s_e_s can be specified using + Within [[ and ]], _c_h_a_r_a_c_t_e_r _c_l_a_s_s_e_s can be specified using the syntax [[::_c_l_a_s_s::]], where _c_l_a_s_s is one of the following classes defined in the POSIX standard: - aallnnuumm aallpphhaa aasscciiii bbllaannkk ccnnttrrll ddiiggiitt ggrraapphh lloowweerr pprriinntt + aallnnuumm aallpphhaa aasscciiii bbllaannkk ccnnttrrll ddiiggiitt ggrraapphh lloowweerr pprriinntt ppuunncctt ssppaaccee uuppppeerr wwoorrdd xxddiiggiitt A character class matches any character belonging to that 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 + 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 + the same collation weight (as defined by the current locale) 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. If the eexxttgglloobb shell option is enabled using the sshhoopptt builtin, several - extended pattern matching operators are recognized. In the following + extended pattern matching operators are recognized. In the following description, a _p_a_t_t_e_r_n_-_l_i_s_t is a list of one or more patterns separated by a ||. Composite patterns may be formed using one or more of the fol- lowing sub-patterns: @@ -1963,63 +2028,71 @@ 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. + 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. - - 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 + 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 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. @@ -2029,22 +2102,22 @@ 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: @@ -2052,27 +2125,27 @@ RREEDDIIRREECCTTIIOONN [_n]<<_w_o_r_d RReeddiirreeccttiinngg OOuuttppuutt - Redirection of output causes the file whose name results from the + 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 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 + 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 specified. If the file does not exist it is created. The general format for appending output is: @@ -2080,11 +2153,11 @@ 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 + There are two formats for redirecting standard output and standard error: &&>>_w_o_r_d @@ -2096,13 +2169,13 @@ 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 + 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. 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: @@ -2116,10 +2189,10 @@ 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: @@ -2128,18 +2201,18 @@ 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 + 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 ``. 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 + allows here-documents within shell scripts to be indented in a natural fashion. HHeerree SSttrriinnggss @@ -2147,12 +2220,11 @@ RREEDDIIRREECCTTIIOONN [_n]<<<<<<_w_o_r_d - The _w_o_r_d undergoes brace expansion, tilde expansion, parameter and - variable expansion, command substitution, arithmetic expansion, and - quote removal. Pathname expansion and word splitting are not per- - formed. 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). + 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). DDuupplliiccaattiinngg FFiillee DDeessccrriippttoorrss The redirection operator @@ -2232,19 +2304,19 @@ AALLIIAASSEESS 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 - before executing any of the commands on that line. 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 com- - mand. As a consequence, aliases defined in a function are not avail- - able until after that function is executed. To be safe, always put - alias definitions on a separate line, and do not use aalliiaass in compound - commands. + 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- + tions on a separate line, and do not use aalliiaass in compound commands. For almost every purpose, aliases are superseded by shell functions. @@ -2273,29 +2345,57 @@ FFUUNNCCTTIIOONNSS 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. - - The FFUUNNCCNNEESSTT variable, if set to a numeric value greater than 0, - defines a maximum function nesting level. Function invocations that + 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 + 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 + 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 + 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 + 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 + 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 - deleted using the --ff option to the uunnsseett builtin. Note that shell - functions and variables with the same name may result in multiple iden- - tically-named entries in the environment passed to the shell's chil- - dren. Care should be taken in cases where this may cause a problem. + 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- @@ -2314,9 +2414,9 @@ AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN _i_d++++ _i_d---- variable post-increment and post-decrement + -- ++ unary minus and plus ++++_i_d ----_i_d variable pre-increment and pre-decrement - -- ++ unary minus and plus !! ~~ logical and bitwise negation **** exponentiation ** // %% multiplication, division, remainder @@ -2365,15 +2465,19 @@ AARRIITTHHMMEETTIICC EEVVAALLUUAATTIIOONN 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. Expressions are formed from the following - unary or binary primaries. BBaasshh handles several filenames specially - when they are used in expressions. If the operating system on which - bbaasshh is running provides these special files, bash will use them; oth- - erwise it will emulate them internally with this behavior: If any _f_i_l_e - argument to one of the primaries 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, is checked. + and arithmetic comparisons. The tteesstt abd [[ 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- + 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- + 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, + 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 @@ -2470,7 +2574,9 @@ CCOONNDDIITTIIOONNAALL EEXXPPRREESSSSIIOONNSS 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. + 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 @@ -2529,43 +2635,44 @@ CCOOMMMMAANNDD EEXXEECCUUTTIIOONN 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 named ccoommmmaanndd__nnoott__ffoouunndd__hhaannddllee. If that function exists, it is invoked - with the original command and the original command's arguments as its - arguments, and the function's exit status becomes the exit status of - the shell. If that function is not defined, the shell prints an error - message and returns an exit status of 127. + in a separate execution environment with the original command and the + original command's arguments as its arguments, and the function's exit + status becomes the exit status of that subshell. If that function is + not defined, the shell prints an error message and returns an exit sta- + tus of 127. - If the search is successful, or if the command name contains one or + If the search is successful, or if the command name contains one or more slashes, the shell executes the named program in a separate execu- tion environment. Argument 0 is set to the name given, and the remain- ing arguments to the command are set to the arguments given, if any. - If this execution fails because the file is not in executable format, - and the file is not a directory, it is assumed to be a _s_h_e_l_l _s_c_r_i_p_t, a - 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 + If this execution fails because the file is not in executable format, + and the file is not a directory, it is assumed to be a _s_h_e_l_l _s_c_r_i_p_t, a + 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. - If the program is a file beginning with ##!!, the remainder of the first - line specifies an interpreter for the program. The shell executes the + If the program is a file beginning with ##!!, the remainder of the first + line specifies an interpreter for the program. The shell executes the specified interpreter on operating systems that do not handle this exe- cutable format themselves. The arguments to the interpreter consist of - a single optional argument following the interpreter name on the first - line of the program, followed by the name of the program, followed by + a single optional argument following the interpreter name on the first + line of the program, followed by the name of the program, followed by the command arguments, if any. CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENNTT - The shell has an _e_x_e_c_u_t_i_o_n _e_n_v_i_r_o_n_m_e_n_t, which consists of the follow- + The shell has an _e_x_e_c_u_t_i_o_n _e_n_v_i_r_o_n_m_e_n_t, which consists of the follow- ing: - +o open files inherited by the shell at invocation, as modified by + +o open files inherited by the shell at invocation, as modified by redirections supplied to the eexxeecc builtin - +o the current working directory as set by ccdd, ppuusshhdd, or ppooppdd, or + +o the current working directory as set by ccdd, ppuusshhdd, or ppooppdd, or inherited by the shell at invocation - +o the file creation mode mask as set by uummaasskk or inherited from + +o the file creation mode mask as set by uummaasskk or inherited from the shell's parent +o current traps set by ttrraapp @@ -2573,238 +2680,245 @@ CCOOMMMMAANNDD EEXXEECCUUTTIIOONN EENNVVIIRROONNMMEENN +o shell parameters that are set by variable assignment or with sseett or inherited from the shell's parent in the environment - +o shell functions defined during execution or inherited from the + +o shell functions defined during execution or inherited from the shell's parent in the environment - +o options enabled at invocation (either by default or with com- + +o options enabled at invocation (either by default or with com- mand-line arguments) or by sseett +o options enabled by sshhoopptt +o shell aliases defined with aalliiaass - +o various process IDs, including those of background jobs, the + +o various process IDs, including those of background jobs, the value of $$$$, and the value of PPPPIIDD - When a simple command other than a builtin or shell function is to be - executed, it is invoked in a separate execution environment that con- - sists of the following. Unless otherwise noted, the values are inher- + When a simple command other than a builtin or shell function is to be + executed, it is invoked in a separate execution environment that con- + sists of the following. Unless otherwise noted, the values are inher- ited from the shell. - +o the shell's open files, plus any modifications and additions + +o the shell's open files, plus any modifications and additions specified by redirections to the command +o the current working directory +o the file creation mode mask - +o shell variables and functions marked for export, along with + +o shell variables and functions marked for export, along with variables exported for the command, passed in the environment +o traps caught by the shell are reset to the values inherited from the shell's parent, and traps ignored by the shell are ignored - A command invoked in this separate environment cannot affect the + A command invoked in this separate environment cannot affect the shell's execution environment. - Command substitution, commands grouped with parentheses, and asynchro- + 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 + 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- 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. Subshells spawned to execute command substitutions inherit the value of - the --ee option from the parent shell. When not in _p_o_s_i_x mode, bbaasshh + 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 + 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. EENNVVIIRROONNMMEENNTT - When a program is invoked it is given an array of strings called the + 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 + The shell provides several ways to manipulate the environment. On invocation, 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 + 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 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 - 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 + ronment is modified, the new value becomes part of the environment, + replacing 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. - The environment for any _s_i_m_p_l_e _c_o_m_m_a_n_d or function may be augmented - temporarily by prefixing it with parameter assignments, as described + The environment for any _s_i_m_p_l_e _c_o_m_m_a_n_d or function may be augmented + temporarily by prefixing it with parameter assignments, as described above in PPAARRAAMMEETTEERRSS. These assignment statements affect only the envi- ronment seen by that command. - If the --kk option is set (see the sseett builtin command below), then _a_l_l - parameter assignments are placed in the environment for a command, not + If the --kk option is set (see the sseett builtin command below), then _a_l_l + parameter assignments are placed in the environment for a command, not just those that precede the command name. - When bbaasshh invokes an external command, the variable __ is set to the + When bbaasshh invokes an external command, the variable __ is set to the full filename of the command and passed to that command in its environ- ment. EEXXIITT SSTTAATTUUSS - The exit status of an executed command is the value returned by the + The exit status of an executed command is the value returned by the _w_a_i_t_p_i_d system call or equivalent function. Exit statuses fall between - 0 and 255, though, as explained below, the shell may use values above + 0 and 255, though, as explained below, the shell may use values above 125 specially. Exit statuses from shell builtins and compound commands are also limited to this range. Under certain circumstances, the shell will use special values to indicate specific failure modes. For the shell's purposes, a command which exits with a zero exit status - has succeeded. An exit status of zero indicates success. A non-zero - exit status indicates failure. When a command terminates on a fatal + has succeeded. An exit status of zero indicates success. A non-zero + 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 + returns 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, the exit status is greater than zero. - 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 + 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. - 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, + unless 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 + 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 + 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. 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 - these inherited handlers. Commands run as a result of command substi- + inherited by the shell from its parent. When job control is not in + effect, 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. - The shell exits by default upon receipt of a SSIIGGHHUUPP. Before exiting, - an interactive shell resends the SSIIGGHHUUPP to all jobs, running or + The shell exits by default upon receipt of a SSIIGGHHUUPP. Before exiting, + an interactive shell resends the SSIIGGHHUUPP to all jobs, running or 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 + 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. - If the hhuuppoonneexxiitt shell option has been set with sshhoopptt, bbaasshh sends a + If the hhuuppoonneexxiitt shell option has been set with sshhoopptt, bbaasshh sends a SSIIGGHHUUPP to all jobs when an interactive login shell exits. - If bbaasshh is waiting for a command to complete and receives a signal for + If bbaasshh is waiting for a command to complete and receives a signal for which a trap has been set, the trap will not be executed until the com- - mand completes. When bbaasshh is waiting for an asynchronous command via - the wwaaiitt builtin, the reception of a signal for which a trap has been + mand completes. When bbaasshh is waiting for an asynchronous command via + the wwaaiitt builtin, the reception of a signal for which a trap has been set will cause the wwaaiitt builtin to return immediately with an exit sta- 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 + _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 + point. A user typically employs this facility via an interactive + interface 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 - currently executing jobs, which may be listed with the jjoobbss command. - When bbaasshh starts a job asynchronously (in the _b_a_c_k_g_r_o_u_n_d), it prints a + The shell associates a _j_o_b with each pipeline. It keeps a table of + currently executing jobs, which may be listed with the jjoobbss command. + When bbaasshh starts a job asynchronously (in the _b_a_c_k_g_r_o_u_n_d), it prints a line that looks like: [1] 25647 indicating that this job is job number 1 and that the process ID of the last process in the pipeline associated with this job is 25647. All of - the processes in a single pipeline are members of the same job. BBaasshh + the processes in a single pipeline are members of the same job. BBaasshh uses the _j_o_b abstraction as the basis for job control. - To facilitate the implementation of the user interface to job control, + To facilitate the implementation of the user interface to job control, the operating system maintains the notion of a _c_u_r_r_e_n_t _t_e_r_m_i_n_a_l _p_r_o_c_e_s_s _g_r_o_u_p _I_D. Members of this process group (processes whose process group ID is equal to the current terminal process group ID) receive keyboard- - generated signals such as SSIIGGIINNTT. These processes are said to be in - the _f_o_r_e_g_r_o_u_n_d. _B_a_c_k_g_r_o_u_n_d processes are those whose process group ID + generated signals such as SSIIGGIINNTT. These processes are said to be in + the _f_o_r_e_g_r_o_u_n_d. _B_a_c_k_g_r_o_u_n_d processes are those whose process group ID differs from the terminal's; such processes are immune to keyboard-gen- erated signals. Only foreground processes are allowed to read from or, - if the user so specifies with stty tostop, write to the terminal. - Background processes which attempt to read from (write to when stty - tostop is in effect) the terminal are sent a SSIIGGTTTTIINN ((SSIIGGTTTTOOUU)) signal - by the kernel's terminal driver, which, unless caught, suspends the + if the user so specifies with stty tostop, write to the terminal. + Background processes which attempt to read from (write to when stty + tostop is in effect) the terminal are sent a SSIIGGTTTTIINN ((SSIIGGTTTTOOUU)) signal + by the kernel's terminal driver, which, unless caught, suspends the process. - If the operating system on which bbaasshh is running supports job control, + If the operating system on which bbaasshh is running supports job control, bbaasshh contains facilities to use it. Typing the _s_u_s_p_e_n_d character (typ- 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, - using the bbgg command to continue it in the background, the ffgg command + 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, + 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 pending output and typeahead to be discarded. There are a number of ways to refer to a job in the shell. The charac- - ter %% introduces a job specification (_j_o_b_s_p_e_c). Job number _n may be + 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 + 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 + 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- + vious job with a --. A single % (with no accompanying job specifica- tion) 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 - foreground. Similarly, ````%%11 &&'''' resumes job 1 in the background, + 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 + foreground. Similarly, ````%%11 &&'''' resumes job 1 in the background, equivalent to ````bbgg %%11''''. - The shell learns immediately whenever a job changes state. Normally, + The shell learns immediately whenever a job changes state. Normally, 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 + 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 + immediately. Any trap on SSIIGGCCHHLLDD is executed for each child that exits. - 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- + 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- ning), the shell prints a warning message, and, if the cchheecckkjjoobbss option - is enabled, lists the jobs and their statuses. The jjoobbss command may - then be used to inspect their status. If a second attempt to exit is - made without an intervening command, the shell does not print another + is enabled, lists the jobs and their statuses. The jjoobbss command may + then be used to inspect their status. If a second attempt to exit is + made without an intervening command, the shell does not print another warning, and any stopped jobs are terminated. + 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. + 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 allows these prompt - strings to be customized by inserting a number of backslash-escaped - special characters that are decoded as follows: + 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: \\aa an ASCII bell character (07) \\dd the date in "Weekday Month Date" format (e.g., "Tue May 26") @@ -3066,185 +3180,201 @@ RREEAADDLLIINNEE Controls whether readline begins with a set of key bindings sim- ilar to _E_m_a_c_s or _v_i. eeddiittiinngg--mmooddee can be set to either eemmaaccss or vvii. + eemmaaccss--mmooddee--ssttrriinngg ((@@)) + 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 emacs editing mode is active. 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 control sequence into the + mode string. eennaabbllee--bbrraacckkeetteedd--ppaassttee ((OOffff)) - When set to OOnn, readline will configure the terminal in a way + 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- - acter as if it had been read from the keyboard. This can pre- - vent pasted characters from being interpreted as editing com- + acter as if it had been read from the keyboard. This can pre- + vent pasted characters from being interpreted as editing com- 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 + pad when it is called. Some systems need this to enable the arrow 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 + 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 + If set to OOnn, tilde expansion is performed when readline attempts 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-- + If set to OOnn, the history code attempts to place point at the + same location on each history line retrieved with pprreevviioouuss--hhiiss-- ttoorryy or nneexxtt--hhiissttoorryy. hhiissttoorryy--ssiizzee ((uunnsseett)) - Set the maximum number of history entries saved in the history - list. If set to zero, any existing history entries are deleted + Set the maximum number of history entries saved in the history + list. If set to zero, any existing history entries are deleted and no new entries are saved. If set to a value less than zero, - the number of history entries is not limited. By default, the - number of history entries is set to the value of the HHIISSTTSSIIZZEE - shell variable. If an attempt is made to set _h_i_s_t_o_r_y_-_s_i_z_e to a + the number of history entries is not limited. By default, the + number of history entries is set to the value of the HHIISSTTSSIIZZEE + shell variable. If an attempt is made to set _h_i_s_t_o_r_y_-_s_i_z_e to a non-numeric value, the maximum number of history entries will be set to 500. hhoorriizzoonnttaall--ssccrroollll--mmooddee ((OOffff)) - When set to OOnn, makes readline use a single line for display, + 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 + becomes longer than the screen width rather than wrapping to a new line. 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), + 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 + 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. - eemmaaccss--mmooddee--ssttrriinngg ((@@)) - This string is displayed immediately before the last line of the - primary prompt when emacs editing mode is active. 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- - trol sequence into the mode string. 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 + 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 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 + tories have a slash appended (subject to the value of mmaarrkk--ddiirreeccttoorriieess). 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 + 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. sshhooww--mmooddee--iinn--pprroommpptt ((OOffff)) - If set to OOnn, add a character to the beginning of the prompt - indicating 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)))) - 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 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 control sequence into the mode string. + 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 + 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- + trol sequence into the mode string. vvii--iinnss--mmooddee--ssttrriinngg ((((iinnss)))) - 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 control sequence into the mode string. + 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- + 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 $$iiff construct allows bindings to be made based on the edit- - ing mode, the terminal being used, or the application using - readline. The text of the test extends to the end of the line; - no characters are required to isolate it. - - mmooddee The mmooddee== form of the $$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 + $$iiff The $$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 + characters are required to isolate it. + + mmooddee The mmooddee== form of the $$iiff directive is used to test + whether readline is in emacs or vi mode. This may be + used in conjunction with the sseett kkeeyymmaapp command, for + instance, to set bindings in the _e_m_a_c_s_-_s_t_a_n_d_a_r_d and + _e_m_a_c_s_-_c_t_l_x keymaps only if readline is starting out in emacs mode. - tteerrmm The tteerrmm== form may be used to include terminal-specific + tteerrmm The tteerrmm== form may be used to include terminal-specific key bindings, perhaps to bind the key sequences output by the terminal's function keys. The word on the right side of the == is tested against both the full name of the ter- - minal and the portion of the terminal name before the - first --. This allows _s_u_n to match both _s_u_n and _s_u_n_-_c_m_d, + minal and the portion of the terminal name before the + first --. This allows _s_u_n to match both _s_u_n and _s_u_n_-_c_m_d, for instance. + vveerrssiioonn + The vveerrssiioonn test may be used to perform comparisons + against specific readline versions. The vveerrssiioonn expands + to the current readline version. The set of comparison + operators includes ==, (and ====), !!==, <<==, >>==, <<, and >>. + The version number supplied on the right side of the + operator consists of a major version number, an optional + decimal point, and an optional minor version (e.g., 77..11). + If the minor version is omitted, it is assumed to be 00. + The operator may be separated from the string vveerrssiioonn and + from the version number argument by whitespace. + aapppplliiccaattiioonn The aapppplliiccaattiioonn construct is used to include application- specific settings. Each program using the readline @@ -3260,6 +3390,16 @@ RREEAADDLLIINNEE "\C-xq": "\eb\"\ef\"" $$eennddiiff + _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 + 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 + against the values _o_n and _o_f_f. + $$eennddiiff This command, as seen in the previous example, terminates an $$iiff command. @@ -3267,51 +3407,51 @@ 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 @@ -3327,17 +3467,29 @@ 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 + the prompt plus the screen width. + nneexxtt--ssccrreeeenn--lliinnee + 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 + not greater than the length of the prompt plus the screen width. 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 + Clear the screen leaving the current 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. @@ -3345,60 +3497,70 @@ RREEAADDLLIINNEE 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 + history line. This is a non-incremental search. + hhiissttoorryy--ssuubbssttrriinngg--sseeaarrcchh--ffoorrwwaarrdd + 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. 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 + 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 + 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. @@ -3407,24 +3569,25 @@ 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 + Perform history expansion on the current line. See HHIISSTTOORRYY EEXXPPAANNSSIIOONN 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. Any - argument is ignored. - eeddiitt--aanndd--eexxeeccuuttee--ccoommmmaanndd ((CC--xxCC--ee)) + 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. @@ -3647,103 +3810,107 @@ RREEAADDLLIINNEE aabboorrtt ((CC--gg)) Abort the current editing command and ring the terminal's bell (subject to the setting of bbeellll--ssttyyllee). - ddoo--uuppppeerrccaassee--vveerrssiioonn ((MM--aa,, MM--bb,, MM--_x,, ......)) - If the metafied character _x is lowercase, run the command that - is bound to the corresponding uppercase character. + ddoo--lloowweerrccaassee--vveerrssiioonn ((MM--AA,, MM--BB,, MM--_x,, ......)) + If the metafied character _x is uppercase, run the command that + is bound to the corresponding metafied lowercase character. The + behavior is undefined if _x is already lowercase. pprreeffiixx--mmeettaa ((EESSCC)) Metafy the next character typed. EESSCC ff is equivalent to MMeettaa--ff. uunnddoo ((CC--__,, CC--xx CC--uu)) Incremental undo, separately remembered for each line. rreevveerrtt--lliinnee ((MM--rr)) - Undo all changes made to this line. This is like executing the - uunnddoo command enough times to return the line to its initial + Undo all changes made to this line. This is like executing the + uunnddoo command enough times to return the line to its initial state. ttiillddee--eexxppaanndd ((MM--&&)) Perform tilde expansion on the current word. sseett--mmaarrkk ((CC--@@,, MM--<<ssppaaccee>>)) - Set the mark to the point. If a numeric argument is supplied, + Set the mark to the point. If a numeric argument is supplied, the mark is set to that position. eexxcchhaannggee--ppooiinntt--aanndd--mmaarrkk ((CC--xx CC--xx)) - Swap the point with the mark. The current cursor position is - set to the saved position, and the old cursor position is saved + Swap the point with the mark. The current cursor position is + set to the saved position, and the old cursor position is saved as the mark. cchhaarraacctteerr--sseeaarrcchh ((CC--]])) A character is read and point is moved to the next occurrence of - that character. A negative count searches for previous occur- + that character. A negative count searches for previous occur- rences. cchhaarraacctteerr--sseeaarrcchh--bbaacckkwwaarrdd ((MM--CC--]])) - A character is read and point is moved to the previous occur- - rence of that character. A negative count searches for subse- + A character is read and point is moved to the previous occur- + rence of that character. A negative count searches for subse- quent occurrences. sskkiipp--ccssii--sseeqquueennccee - Read enough characters to consume a multi-key sequence such as - those defined for keys like Home and End. Such sequences begin + Read enough characters to consume a multi-key sequence such as + those defined for keys like Home and End. Such sequences begin with a Control Sequence Indicator (CSI), usually ESC-[. If this - sequence is bound to "\[", keys producing such sequences will - have no effect unless explicitly bound to a readline command, - instead of inserting stray characters into the editing buffer. + sequence is bound to "\[", keys producing such sequences will + have no effect unless explicitly bound to a readline command, + instead of inserting stray characters into the editing buffer. This is unbound by default, but usually bound to ESC-[. iinnsseerrtt--ccoommmmeenntt ((MM--##)) - Without a numeric argument, the value of the readline ccoomm-- - mmeenntt--bbeeggiinn variable is inserted at the beginning of the current + Without a numeric argument, the value of the readline ccoomm-- + mmeenntt--bbeeggiinn variable is inserted at the beginning of the current line. If a numeric argument is supplied, this command acts as a - toggle: if the characters at the beginning of the line do not - match the value of ccoommmmeenntt--bbeeggiinn, the value is inserted, other- + toggle: if the characters at the beginning of the line do not + match the value of ccoommmmeenntt--bbeeggiinn, the value is inserted, other- wise the characters in ccoommmmeenntt--bbeeggiinn are deleted from the begin- - 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 + 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. 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 + 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. 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 + 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. 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 - numeric argument is supplied, an asterisk is appended before + The list of expansions that would have been generated by + gglloobb--eexxppaanndd--wwoorrdd is displayed, and the line is redrawn. If a + numeric argument is supplied, an asterisk is appended before pathname expansion. dduummpp--ffuunnccttiioonnss - Print all of the functions and their key bindings to the read- + Print all of the functions and their key bindings to the read- line output stream. If a numeric argument is supplied, the out- - put is formatted in such a way that it can be made part of an + put is formatted in such a way that it can be made part of an _i_n_p_u_t_r_c file. dduummpp--vvaarriiaabblleess Print all of the settable readline variables and their values to - the readline output stream. If a numeric argument is supplied, - the output is formatted in such a way that it can be made part + the readline output stream. If a numeric argument is supplied, + the output is formatted in such a way that it can be made part of an _i_n_p_u_t_r_c file. dduummpp--mmaaccrrooss - Print all of the readline key sequences bound to macros and the - strings they output. If a numeric argument is supplied, the + Print all of the readline key sequences bound to macros and the + strings they output. If a numeric argument is supplied, the output is formatted in such a way that it can be made part of an _i_n_p_u_t_r_c file. ddiissppllaayy--sshheellll--vveerrssiioonn ((CC--xx CC--vv)) Display version information about the current instance of bbaasshh. PPrrooggrraammmmaabbllee CCoommpplleettiioonn - When word completion is attempted for an argument to a command for - which a completion specification (a _c_o_m_p_s_p_e_c) has been defined using - the ccoommpplleettee builtin (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below), the program- + When word completion is attempted for an argument to a command for + which a completion specification (a _c_o_m_p_s_p_e_c) has been defined using + the ccoommpplleettee builtin (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below), the program- mable completion facilities are invoked. - First, the command name is identified. If the command word is the - empty string (completion attempted at the beginning of an empty line), - any compspec defined with the --EE option to ccoommpplleettee is used. If a - compspec has been defined for that command, the compspec is used to + First, the command name is identified. If the command word is the + empty string (completion attempted at the beginning of an empty line), + any compspec defined with the --EE option to ccoommpplleettee is used. If a + compspec has been defined for that command, the compspec is used to generate the list of possible completions for the word. If the command - word is a full pathname, a compspec for the full pathname is searched - for first. If no compspec is found for the full pathname, an attempt - is made to find a compspec for the portion following the final slash. - If those searches do not result in a compspec, any compspec defined - with the --DD option to ccoommpplleettee is used as the default. + word is a full pathname, a compspec for the full pathname is searched + for first. If no compspec is found for the full pathname, an attempt + is made to find a compspec for the portion following the final slash. + If those searches do not result in a compspec, any compspec defined + with the --DD option to ccoommpplleettee is used as the default. If there is no + default compspec, bbaasshh attempts alias expansion on the command word as + a final resort, and attempts to find a compspec for the command word + from any successful expansion. Once a compspec has been found, it is used to generate the list of matching words. If a compspec is not found, the default bbaasshh comple- @@ -3871,8 +4038,8 @@ HHIISSTTOORRYY SSIIZZEE is unset, or set to null, a non-numeric value, or a numeric value less than zero, the history file is not truncated. When the history file is read, lines beginning with the history comment character fol- - lowed immediately by a digit are interpreted as timestamps for the pre- - ceding history line. These timestamps are optionally displayed depend- + lowed immediately by a digit are interpreted as timestamps for the fol- + lowing history line. These timestamps are optionally displayed depend- ing on the value of the HHIISSTTTTIIMMEEFFOORRMMAATT variable. When a shell with history enabled exits, the last $$HHIISSTTSSIIZZEE lines are copied from the history list to $$HHIISSTTFFIILLEE. If the hhiissttaappppeenndd shell option is enabled @@ -3908,7 +4075,7 @@ HHIISSTTOORRYY HHIISSTTOORRYY EEXXPPAANNSSIIOONN The shell supports a history expansion feature that is similar to the - history expansion in ccsshh.. This section describes what syntax features + history expansion in ccsshh. This section describes what syntax features are available. This feature is enabled by default for interactive shells, and can be disabled using the ++HH option to the sseett builtin com- mand (see SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS below). Non-interactive shells do not @@ -3920,96 +4087,97 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN commands quickly. History expansion is performed immediately after a complete line is - read, before the shell breaks it into words. 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 that line that are acted upon are - _w_o_r_d_s. Various _m_o_d_i_f_i_e_r_s are available to manipulate the selected - words. The line is broken into words in the same fashion as when read- - ing input, so that several _m_e_t_a_c_h_a_r_a_c_t_e_r-separated words surrounded by - quotes are considered one word. History expansions are introduced by - the appearance of the history expansion 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 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, - tab, newline, carriage return, and ==. If the eexxttgglloobb shell option 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 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 + that line that are acted upon are _w_o_r_d_s. Various _m_o_d_i_f_i_e_r_s are avail- + able to manipulate the selected words. The line is broken into words + in the same fashion as when reading input, so that several _m_e_t_a_c_h_a_r_a_c_- + _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. + + Several characters inhibit history expansion if found immediately fol- + lowing the history expansion character, even if it is unquoted: space, + tab, newline, carriage return, and ==. If the eexxttgglloobb shell option is 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 + 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 - rreeaaddlliinnee is being used, history substitutions are not immediately - passed to the shell parser. Instead, the expanded line is reloaded + 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 - is being used, and the hhiissttrreeeeddiitt shell option is enabled, a failed - history substitution will be reloaded into the rreeaaddlliinnee editing buffer - for correction. The --pp option to the hhiissttoorryy builtin command may be - used to see what a history expansion will do before using it. The --ss + is being used, and the hhiissttrreeeeddiitt shell option is enabled, a failed + history substitution will be reloaded into the rreeaaddlliinnee editing buffer + for correction. The --pp option to the hhiissttoorryy builtin command may be + used to see what a history expansion will do before using it. The --ss option to the hhiissttoorryy builtin may be used to add commands to the end of - the history list without actually executing them, so that they are + the history list without actually executing them, so that they are available for subsequent recall. - The shell allows control of the various characters used by the history + The shell allows control of the various characters used by the history expansion mechanism (see the description of hhiissttcchhaarrss above under SShheellll - VVaarriiaabblleess). The shell uses the history comment character to mark his- + VVaarriiaabblleess). The shell uses the history comment character to mark his- tory timestamps when writing the history file. EEvveenntt DDeessiiggnnaattoorrss - An event designator is a reference to a command line entry in the his- - tory list. Unless the reference is absolute, events are relative to + An event designator is a reference to a command line entry in the his- + tory list. Unless the reference is absolute, events are relative to the current position in the history list. - !! Start a history substitution, except when followed by a bbllaannkk, - newline, carriage return, = or ( (when the eexxttgglloobb shell option + !! Start a history substitution, except when followed by a bbllaannkk, + newline, carriage return, = or ( (when the eexxttgglloobb shell option is enabled using the sshhoopptt builtin). !!_n Refer to command line _n. !!--_n Refer to the current command minus _n. !!!! Refer to the previous command. This is a synonym for `!-1'. !!_s_t_r_i_n_g - Refer to the most recent command preceding the current position + Refer to the most recent command preceding the current position in the history list starting with _s_t_r_i_n_g. !!??_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 + 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. ^^_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/'' + 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/'' (see MMooddiiffiieerrss below). !!## The entire command line typed so far. WWoorrdd DDeessiiggnnaattoorrss - Word designators are used to select desired words from the event. A :: - separates the event specification from the word designator. It may be - omitted if the word designator begins with a ^^, $$, **, --, or %%. Words - are numbered from the beginning of the line, with the first word being - denoted by 0 (zero). Words are inserted into the current line sepa- + Word designators are used to select desired words from the event. A :: + separates the event specification from the word designator. It may be + omitted if the word designator begins with a ^^, $$, **, --, or %%. Words + are numbered from the beginning of the line, with the first word being + denoted by 0 (zero). Words are inserted into the current line sepa- rated by single spaces. 00 ((zzeerroo)) The zeroth word. For the shell, this is the command word. _n The _nth word. ^^ The first argument. That is, word 1. - $$ The last word. This is usually the last argument, but will + $$ 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. _x--_y A range of words; `-_y' abbreviates `0-_y'. - ** All of the words but the zeroth. This is a synonym for `_1_-_$'. - It is not an error to use ** if there is just one word in the + ** All of the words but the zeroth. This is a synonym for `_1_-_$'. + 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. - 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 + After the optional word designator, there may appear a sequence of one or more of the following modifiers, each preceded by a `:'. hh Remove a trailing filename component, leaving only the head. @@ -4018,80 +4186,80 @@ HHIISSTTOORRYY EEXXPPAANNSSIIOONN ee Remove all but the trailing suffix. 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 + xx Quote the substituted words as with qq, but break into words at bbllaannkkss and newlines. 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- + 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. && 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 + 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 + GG Apply the following `ss' modifier once to each word in the event line. SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS Unless otherwise noted, each builtin command documented in this section as accepting options preceded by -- accepts ---- to signify the end of the - options. The ::, ttrruuee, ffaallssee, and tteesstt builtins do not accept options - and do not treat ---- specially. The eexxiitt, llooggoouutt, rreettuurrnn, bbrreeaakk, ccoonn-- - ttiinnuuee, lleett, and sshhiifftt builtins accept and process arguments beginning - with -- without requiring ----. Other builtins that accept arguments but - are not specified as accepting options interpret arguments beginning - with -- as invalid options and require ---- to prevent this interpreta- + options. The ::, ttrruuee, ffaallssee, and tteesstt/[[ builtins do not accept options + and do not treat ---- specially. The eexxiitt, llooggoouutt, rreettuurrnn, bbrreeaakk, ccoonn-- + ttiinnuuee, lleett, and sshhiifftt builtins accept and process arguments beginning + with -- without requiring ----. Other builtins that accept arguments but + are not specified as accepting options interpret arguments beginning + with -- as invalid options and require ---- to prevent this interpreta- tion. :: [_a_r_g_u_m_e_n_t_s] - No effect; the command does nothing beyond expanding _a_r_g_u_m_e_n_t_s + No effect; the command does nothing beyond expanding _a_r_g_u_m_e_n_t_s and performing any specified redirections. The return status is zero. .. _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- - 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 + 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- + 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. - When bbaasshh is not in _p_o_s_i_x _m_o_d_e, the current directory is - 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 + When bbaasshh is not in _p_o_s_i_x _m_o_d_e, the current directory is + 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 cannot be read. aalliiaass [--pp] [_n_a_m_e[=_v_a_l_u_e] ...] AAlliiaass with no arguments or with the --pp option prints the list of - aliases in the form aalliiaass _n_a_m_e=_v_a_l_u_e on standard output. When - arguments are supplied, an alias is defined for each _n_a_m_e whose - _v_a_l_u_e is given. A trailing space in _v_a_l_u_e causes the next word + aliases in the form aalliiaass _n_a_m_e=_v_a_l_u_e on standard output. When + arguments are supplied, an alias is defined for each _n_a_m_e whose + _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 + 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 defined. bbgg [_j_o_b_s_p_e_c ...] - Resume each suspended job _j_o_b_s_p_e_c in the background, as if it + Resume each suspended job _j_o_b_s_p_e_c in the background, as if it had been started with &&. If _j_o_b_s_p_e_c is not present, the shell's - notion of the _c_u_r_r_e_n_t _j_o_b is used. bbgg _j_o_b_s_p_e_c returns 0 unless - run when job control is disabled or, when run with job control - enabled, any specified _j_o_b_s_p_e_c was not found or was started + notion of the _c_u_r_r_e_n_t _j_o_b is used. bbgg _j_o_b_s_p_e_c returns 0 unless + run when job control is disabled or, when run with job control + enabled, any specified _j_o_b_s_p_e_c was not found or was started without job control. bbiinndd [--mm _k_e_y_m_a_p] [--llppssvvPPSSVVXX] @@ -4100,29 +4268,29 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS bbiinndd [--mm _k_e_y_m_a_p] --xx _k_e_y_s_e_q:_s_h_e_l_l_-_c_o_m_m_a_n_d bbiinndd [--mm _k_e_y_m_a_p] _k_e_y_s_e_q:_f_u_n_c_t_i_o_n_-_n_a_m_e 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'. + 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: --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_- - _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_-_m_o_v_e_, _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 (_v_i_-_m_o_v_e - is also a synonym); _e_m_a_c_s is equivalent to _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_-_m_o_v_e_, _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 (_v_i_-_m_o_v_e + is also a synonym); _e_m_a_c_s is equivalent to _e_m_a_c_s_-_s_t_a_n_- _d_a_r_d. --ll List the names of all rreeaaddlliinnee functions. - --pp Display rreeaaddlliinnee function names and bindings in such a + --pp Display rreeaaddlliinnee function names and bindings in such a way that they can be re-read. --PP List current rreeaaddlliinnee function names and bindings. - --ss Display rreeaaddlliinnee key sequences bound to macros and the - strings they output in such a way that they can be re- + --ss Display rreeaaddlliinnee key sequences bound to macros and the + strings they output in such a way that they can be re- read. - --SS Display rreeaaddlliinnee key sequences bound to macros and the + --SS Display rreeaaddlliinnee key sequences bound to macros and the strings they output. - --vv Display rreeaaddlliinnee variable names and values in such a way + --vv Display rreeaaddlliinnee variable names and values in such a way that they can be re-read. --VV List current rreeaaddlliinnee variable names and values. --ff _f_i_l_e_n_a_m_e @@ -4134,125 +4302,132 @@ 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 - the RREEAADDLLIINNEE__LLIINNEE variable to the contents of the rreeaadd-- - lliinnee line buffer and the RREEAADDLLIINNEE__PPOOIINNTT variable to the + 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 + 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 + 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 + --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 + 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 + exited. 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 + directory 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 + 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 + 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 + 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. 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] [--DDEE] [--AA _a_c_t_i_o_n] [--GG _g_l_o_b_- + 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 [--DDEE] [_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 - completion specifications are printed in a way that allows them + 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 + completion specifications are printed in a way that allows them to be reused as input. The --rr option removes a completion spec- - ification for each _n_a_m_e, or, if no _n_a_m_es are supplied, all com- - pletion specifications. The --DD option indicates that the - remaining options and actions 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 the remaining options and actions should - apply to ``empty'' command completion; that is, completion - attempted on a blank line. + ification for each _n_a_m_e, or, if no _n_a_m_es are supplied, all com- + pletion specifications. The --DD option indicates that other sup- + plied options and actions should apply to the ``default'' com- + mand completion; that is, completion attempted on a command for + which no completion has previously been defined. The --EE option + 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 + 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 + over --EE, and both take precedence over --II. If any of --DD, --EE, or + --II are supplied, any other _n_a_m_e arguments are ignored; these + completions only apply to the case specified by the option. The process of applying these completion specifications when word completion is attempted is described above under PPrrooggrraamm-- @@ -4361,9 +4536,11 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --WW _w_o_r_d_l_i_s_t The _w_o_r_d_l_i_s_t is split using the characters in the IIFFSS special variable as delimiters, and each resultant word - is expanded. The possible completions are the members - of the resultant list which match the word being com- - pleted. + is expanded. Shell quoting is honored within _w_o_r_d_l_i_s_t, + in order to provide a mechanism for the words to contain + shell metacharacters or characters in the value of IIFFSS. + The possible completions are the members of the resul- + tant list which match the word being completed. --XX _f_i_l_t_e_r_p_a_t _f_i_l_t_e_r_p_a_t is a pattern as used for pathname expansion. It is applied to the list of possible completions gener- @@ -4378,18 +4555,22 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS for a _n_a_m_e for which no specification exists, or an error occurs adding a completion specification. - ccoommppoopptt [--oo _o_p_t_i_o_n] [--DDEE] [++oo _o_p_t_i_o_n] [_n_a_m_e] + 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 the remaining + described above. The --DD option indicates that other supplied options 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 the - remaining options should apply to ``empty'' command completion; - that is, completion attempted on a blank line. + 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- + mand delimiter such as ;; or ||, which is usually command name + completion. The return value is true unless an invalid option is supplied, an attempt is made to modify the options for a _n_a_m_e for which no @@ -4455,16 +4636,16 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS environment. Using `+' instead of `-' turns off the attribute instead, with - the exceptions that ++aa may not be used to destroy an array vari- - able 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 vari- - able 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 assignment - 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 + 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 + 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 @@ -4579,141 +4760,142 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS 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. If _c_o_m_m_a_n_d is not specified, any redi- - rections take effect in the current shell, and the return status - is 0. If there is a redirection error, the return status is 1. + 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- + 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 --nn option suppresses the command numbers when listing. The - --rr option reverses the order of the commands. If the --ll option - is given, the commands are listed on standard output. Other- - wise, the editor given by _e_n_a_m_e is invoked on a file containing - those commands. If _e_n_a_m_e is not given, the value of the FFCCEEDDIITT - variable is used, and the value of EEDDIITTOORR if FFCCEEDDIITT is not set. - If neither variable is set, _v_i is used. When editing is com- + The --nn option suppresses the command numbers when listing. The + --rr option reverses the order of the commands. If the --ll option + is given, the commands are listed on standard output. Other- + wise, the editor given by _e_n_a_m_e is invoked on a file containing + those commands. If _e_n_a_m_e is not given, the value of the FFCCEEDDIITT + variable is used, and the value of EEDDIITTOORR if FFCCEEDDIITT is not set. + If neither variable is set, _v_i is used. When editing is com- plete, the edited commands are echoed and executed. - In the second form, _c_o_m_m_a_n_d is re-executed after each instance - of _p_a_t is replaced by _r_e_p. _C_o_m_m_a_n_d is intepreted the same as - _f_i_r_s_t above. A useful alias to use with this is ``r="fc -s"'', - so that typing ``r cc'' runs the last command beginning with + In the second form, _c_o_m_m_a_n_d is re-executed after each instance + of _p_a_t is replaced by _r_e_p. _C_o_m_m_a_n_d is interpreted the same as + _f_i_r_s_t above. A useful alias to use with this is ``r="fc -s"'', + 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 - lines out of range. If the --ee option is supplied, the return + 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 + 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 - form is used, the return status is that of the command re-exe- - cuted, unless _c_m_d does not specify a valid history line, in + form is used, the return status is that of the command re-exe- + cuted, unless _c_m_d does not specify a valid history line, in which case ffcc returns failure. ffgg [_j_o_b_s_p_e_c] - Resume _j_o_b_s_p_e_c in the foreground, and make it the current job. + Resume _j_o_b_s_p_e_c in the foreground, and make it the current job. If _j_o_b_s_p_e_c is not present, the shell's notion of the _c_u_r_r_e_n_t _j_o_b - is used. The return value is that of the command placed into - the foreground, or failure if run when job control is disabled + is used. The return value is that of the command placed into + the foreground, or failure if run when job control is disabled or, when run with job control enabled, if _j_o_b_s_p_e_c does not spec- - ify a valid job or _j_o_b_s_p_e_c specifies a job that was started + 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 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 - places the next option in the shell variable _n_a_m_e, initializing + 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 + 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 + 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. - When the end of options is encountered, ggeettooppttss exits with a - return value greater than zero. OOPPTTIINNDD is set to the index of + 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 ?. - ggeettooppttss normally parses the positional parameters, but if more + 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- + 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 + 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 + 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- + 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 + 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. 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 @@ -4725,50 +4907,59 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS hhiissttoorryy [[_n]] hhiissttoorryy --cc hhiissttoorryy --dd _o_f_f_s_e_t + hhiissttoorryy --dd _s_t_a_r_t-_e_n_d hhiissttoorryy --aannrrww [_f_i_l_e_n_a_m_e] hhiissttoorryy --pp _a_r_g [_a_r_g _._._.] 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. - --aa Append the ``new'' history lines to the history file. - These are history lines entered since the beginning of + 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 + 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 + 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 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 + appended 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. @@ -4777,208 +4968,210 @@ 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 + _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. 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 + --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. 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 + 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 + 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. - --nn Copy at most _c_o_u_n_t lines. If _c_o_u_n_t is 0, all lines are + --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 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 + 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 + --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 + ++_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 + 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. - Arguments to non-string format specifiers are treated as C con- + Arguments to non-string format specifiers are treated as C con- stants, except that a leading plus or minus sign is allowed, and - if the leading character is a single or double quote, the value + if the leading character is a single or double quote, the value is the ASCII value of the following character. - The _f_o_r_m_a_t is reused as necessary to consume all of the _a_r_g_u_- + The _f_o_r_m_a_t is reused as necessary to consume all of the _a_r_g_u_- _m_e_n_t_s. If the _f_o_r_m_a_t requires more _a_r_g_u_m_e_n_t_s than are supplied, - the extra format specifications behave as if a zero value or - null string, as appropriate, had been supplied. The return + the extra format specifications behave as if a zero value or + null string, as appropriate, had been supplied. The return value is zero on success, non-zero on failure. ppuusshhdd [--nn] [+_n] [-_n] 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. + 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. 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 + --nn Suppresses the normal change of directory when rotating + or adding directories to the stack, so that only the stack is manipulated. - ++_n Rotates the stack so that the _nth directory (counting - from the left of the list shown by ddiirrss, starting with + ++_n Rotates the stack so that the _nth directory (counting + from the left of the list shown by ddiirrss, starting with zero) is at the top. - --_n Rotates the stack so that the _nth directory (counting - from the right of the list shown by ddiirrss, starting with + --_n Rotates the stack so that the _nth directory (counting + from the right of the list shown by ddiirrss, starting with zero) is at the top. _d_i_r Adds _d_i_r to the directory stack at the top, making it the - new current working directory as if it had been supplied + new current working directory as if it had been supplied as the argument to the ccdd builtin. If the ppuusshhdd command is successful, a ddiirrss is performed as well. - If the first form is used, ppuusshhdd returns 0 unless the cd to _d_i_r - fails. With the second form, ppuusshhdd returns 0 unless the direc- - tory stack is empty, a non-existent directory stack element is - specified, or the directory change to the specified new current + If the first form is used, ppuusshhdd returns 0 unless the cd to _d_i_r + fails. With the second form, ppuusshhdd returns 0 unless the direc- + tory stack is empty, a non-existent directory stack element is + specified, or the directory change to the specified new current directory fails. ppwwdd [--LLPP] - Print the absolute pathname of the current working directory. + Print the absolute pathname of the current working directory. The pathname printed contains no symbolic links if the --PP option 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 + 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. 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 + 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 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 + 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 (\\) may be used to remove any special meaning for the next char- - acter read and for line continuation. Options, if supplied, + 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 @@ -4986,12 +5179,15 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS new values are assigned. Other _n_a_m_e arguments are ignored. --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. + 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 + string, rreeaadd will terminate a line when it reads a NUL + character. --ee If the standard input is coming from a terminal, rreeaaddlliinnee - (see RREEAADDLLIINNEE above) is used to obtain the line. Read- - line uses the current (or default, if line editing was - not previously active) editing settings. + (see RREEAADDLLIINNEE above) is used to obtain the line. Read- + line uses the current (or default, if line editing was + not previously active) editing settings, but uses Read- + line's default filename completion. --ii _t_e_x_t If rreeaaddlliinnee is being used to read the line, _t_e_x_t is placed into the editing buffer before editing begins. @@ -5016,8 +5212,8 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS displayed only if input is coming from a terminal. --rr Backslash does not act as an escape character. The back- slash is considered to be part of the line. In particu- - lar, a backslash-newline pair may not be used as a line - continuation. + lar, a backslash-newline pair may not then be used as a + line continuation. --ss Silent mode. If input is coming from a terminal, charac- ters are not echoed. --tt _t_i_m_e_o_u_t @@ -5066,7 +5262,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS 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 + 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 @@ -5085,7 +5281,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS 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 mode, only shell variables are listed. + 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- @@ -5279,64 +5475,74 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS --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 - whether or not each is set. The --pp option causes output to be - displayed in a form that may be reused as input. Other options - have the following meanings: + 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: --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 + options, 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: - 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- + 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- 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 + second exit is attempted without an intervening command + (see JJOOBB CCOONNTTRROOLL above). The shell always postpones exiting if any jobs are stopped. cchheecckkwwiinnssiizzee - If set, bbaasshh checks the window size after each command - and, if necessary, updates the values of LLIINNEESS and CCOOLL-- - UUMMNNSS. + 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. + 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 @@ -5363,7 +5569,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS rupt; previous versions continue with the next command in the list. ccoommppaatt4411 - If set, bbaasshh, when in _p_o_s_i_x mode, treats a single quote + 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 @@ -5384,6 +5590,10 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS 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. ccoommpplleettee__ffuullllqquuoottee If set, bbaasshh quotes all shell metacharacters in file- names and directory names when performing completion. @@ -5409,7 +5619,9 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS 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 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 @@ -5513,37 +5725,55 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS 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. + 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 + 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- + 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 + If set, and rreeaaddlliinnee is being used, bbaasshh will not attempt 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 + 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 + 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- + 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, + 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. pprroommppttvvaarrss If set, prompt strings undergo parameter expansion, com- mand substitution, arithmetic expansion, and quote @@ -5755,7 +5985,7 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS 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- + 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. @@ -5794,22 +6024,25 @@ SSHHEELLLL BBUUIILLTTIINN CCOOMMMMAANNDDSS sequently reset. The exit status is true unless a _n_a_m_e is read- only. - wwaaiitt [--nn] [_n _._._.] + wwaaiitt [--ffnn] [_i_d _._._.] Wait for each specified child process and return its termination - status. Each _n 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 _n is not given, all currently active child pro- + 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 _n 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. + 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. RREESSTTRRIICCTTEEDD SSHHEELLLL If bbaasshh is started with the name rrbbaasshh, or the --rr option is supplied at - invocation, the shell becomes restricted. A restricted shell is used - to set up an environment more controlled than the standard shell. It - behaves identically to bbaasshh with the exception that the following are + invocation, the shell becomes restricted. A restricted shell is used + to set up an environment more controlled than the standard shell. It + behaves identically to bbaasshh with the exception that the following are disallowed or not performed: +o changing directories with ccdd @@ -5818,16 +6051,16 @@ RREESSTTRRIICCTTEEDD SSHHEELLLL +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 + +o specifying a filename containing a slash as an argument to the --pp option to the hhaasshh builtin command - +o importing function definitions from the shell environment at + +o importing function definitions from the shell environment at startup - +o parsing the value of SSHHEELLLLOOPPTTSS from the shell environment at + +o parsing the value of SSHHEELLLLOOPPTTSS from the shell environment at startup +o redirecting output using the >, >|, <>, >&, &>, and >> redirect- @@ -5836,10 +6069,10 @@ RREESSTTRRIICCTTEEDD SSHHEELLLL +o using the eexxeecc builtin command to replace the shell with another command - +o adding or deleting builtin commands with the --ff and --dd options + +o adding or deleting builtin commands with the --ff and --dd options to the eennaabbllee builtin command - +o using the eennaabbllee builtin command to enable disabled shell + +o using the eennaabbllee builtin command to enable disabled shell builtins +o specifying the --pp option to the ccoommmmaanndd builtin command @@ -5849,14 +6082,14 @@ RREESSTTRRIICCTTEEDD SSHHEELLLL These restrictions are enforced after any startup files are read. When a command that is found to be a shell script is executed (see CCOOMM-- - MMAANNDD EEXXEECCUUTTIIOONN above), rrbbaasshh turns off any restrictions in the shell + MMAANNDD EEXXEECCUUTTIIOONN above), rrbbaasshh turns off any restrictions in the shell spawned to execute the script. SSEEEE AALLSSOO _B_a_s_h _R_e_f_e_r_e_n_c_e _M_a_n_u_a_l, Brian Fox and Chet Ramey _T_h_e _G_n_u _R_e_a_d_l_i_n_e _L_i_b_r_a_r_y, Brian Fox and Chet Ramey _T_h_e _G_n_u _H_i_s_t_o_r_y _L_i_b_r_a_r_y, Brian Fox and Chet Ramey - _P_o_r_t_a_b_l_e _O_p_e_r_a_t_i_n_g _S_y_s_t_e_m _I_n_t_e_r_f_a_c_e _(_P_O_S_I_X_) _P_a_r_t _2_: _S_h_e_l_l _a_n_d _U_t_i_l_i_- + _P_o_r_t_a_b_l_e _O_p_e_r_a_t_i_n_g _S_y_s_t_e_m _I_n_t_e_r_f_a_c_e _(_P_O_S_I_X_) _P_a_r_t _2_: _S_h_e_l_l _a_n_d _U_t_i_l_i_- _t_i_e_s, IEEE -- http://pubs.opengroup.org/onlinepubs/9699919799/ http://tiswww.case.edu/~chet/bash/POSIX -- a description of posix mode @@ -5874,7 +6107,7 @@ FFIILLEESS _~_/_._b_a_s_h_r_c The individual per-interactive-shell startup file _~_/_._b_a_s_h___l_o_g_o_u_t - The individual login shell cleanup file, executed when a login + The individual login shell cleanup file, executed when a login shell exits _~_/_._i_n_p_u_t_r_c Individual _r_e_a_d_l_i_n_e initialization file @@ -5888,14 +6121,14 @@ AAUUTTHHOORRSS BBUUGG RREEPPOORRTTSS If you find a bug in bbaasshh,, you should report it. But first, you should - make sure that it really is a bug, and that it appears in the latest - version of bbaasshh. The latest version is always available from + make sure that it really is a bug, and that it appears in the latest + version of bbaasshh. The latest version is always available from _f_t_p_:_/_/_f_t_p_._g_n_u_._o_r_g_/_p_u_b_/_g_n_u_/_b_a_s_h_/. - Once you have determined that a bug actually exists, use the _b_a_s_h_b_u_g - command to submit a bug report. If you have a fix, you are encouraged - to mail that as well! Suggestions and `philosophical' bug reports may - be mailed to _b_u_g_-_b_a_s_h_@_g_n_u_._o_r_g or posted to the Usenet newsgroup + Once you have determined that a bug actually exists, use the _b_a_s_h_b_u_g + command to submit a bug report. If you have a fix, you are encouraged + to mail that as well! Suggestions and `philosophical' bug reports may + be mailed to _b_u_g_-_b_a_s_h_@_g_n_u_._o_r_g or posted to the Usenet newsgroup ggnnuu..bbaasshh..bbuugg. ALL bug reports should include: @@ -5906,7 +6139,7 @@ BBUUGG RREEPPOORRTTSS A description of the bug behaviour A short script or `recipe' which exercises the bug - _b_a_s_h_b_u_g inserts the first three items automatically into the template + _b_a_s_h_b_u_g inserts the first three items automatically into the template it provides for filing a bug report. Comments and bug reports concerning this manual page should be directed @@ -5923,10 +6156,10 @@ BBUUGGSS Shell builtin commands and functions are not stoppable/restartable. Compound commands and command sequences of the form `a ; b ; c' are not - handled gracefully when process suspension is attempted. When a - process is stopped, the shell immediately executes the next command in - the sequence. It suffices to place the sequence of commands between - parentheses to force it into a subshell, which may be stopped as a + handled gracefully when process suspension is attempted. When a + process is stopped, the shell immediately executes the next command in + the sequence. It suffices to place the sequence of commands between + parentheses to force it into a subshell, which may be stopped as a unit. Array variables may not (yet) be exported. @@ -5935,4 +6168,4 @@ BBUUGGSS -GNU Bash 4.4 2016 August 26 BASH(1) +GNU Bash 5.0 2018 December 7 BASH(1) |