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diff --git a/doc/bash.info b/doc/bash.info index 67fb0cb6..4c9909dc 100644 --- a/doc/bash.info +++ b/doc/bash.info @@ -1,9 +1,9 @@ This is bash.info, produced by makeinfo version 6.8 from bashref.texi. This text is a brief description of the features that are present in the -Bash shell (version 5.2, 20 April 2023). +Bash shell (version 5.2, 14 May 2023). - This is Edition 5.2, last updated 20 April 2023, of 'The GNU Bash + This is Edition 5.2, last updated 14 May 2023, of 'The GNU Bash Reference Manual', for 'Bash', Version 5.2. Copyright (C) 1988-2023 Free Software Foundation, Inc. @@ -26,10 +26,10 @@ Bash Features ************* This text is a brief description of the features that are present in the -Bash shell (version 5.2, 20 April 2023). The Bash home page is +Bash shell (version 5.2, 14 May 2023). The Bash home page is <http://www.gnu.org/software/bash/>. - This is Edition 5.2, last updated 20 April 2023, of 'The GNU Bash + This is Edition 5.2, last updated 14 May 2023, of 'The GNU Bash Reference Manual', for 'Bash', Version 5.2. Bash contains features that appear in other popular shells, and some @@ -418,8 +418,8 @@ File: bash.info, Node: ANSI-C Quoting, Next: Locale Translation, Prev: Double 3.1.2.4 ANSI-C Quoting ...................... -Character sequences of the form $'STRING' are treated as a special kind -of single quotes. The sequence expands to STRING, with +Character sequences of the form '$'STRING'' are treated as a special +kind of single quotes. The sequence expands to STRING, with backslash-escaped characters in STRING replaced as specified by the ANSI C standard. Backslash escape sequences, if present, are decoded as follows: @@ -2239,11 +2239,11 @@ File: bash.info, Node: Command Substitution, Next: Arithmetic Expansion, Prev -------------------------- Command substitution allows the output of a command to replace the -command itself. Command substitution occurs when a command is enclosed -as follows: +command itself. The standard form of command substitution occurs when a +command is enclosed as follows: $(COMMAND) -or - `COMMAND` +or (deprecated) + `COMMAND`. Bash performs the expansion by executing COMMAND in a subshell environment and replacing the command substitution with the standard @@ -2252,17 +2252,64 @@ newlines are not deleted, but they may be removed during word splitting. The command substitution '$(cat FILE)' can be replaced by the equivalent but faster '$(< FILE)'. - When the old-style backquote form of substitution is used, backslash -retains its literal meaning except when followed by '$', '`', or '\'. -The first backquote not preceded by a backslash terminates the command + With the old-style backquote form of substitution, backslash retains +its literal meaning except when followed by '$', '`', or '\'. The first +backquote not preceded by a backslash terminates the command substitution. When using the '$(COMMAND)' form, all characters between the parentheses make up the command; none are treated specially. + There is an alternate form of command substitution: + + ${C COMMAND; } + +which executes COMMAND in the current execution environment. This means +that side effects of COMMAND take effect immediately in the current +execution environment and persist in the current environment after the +command completes (e.g., the 'exit' builtin will exit the shell). + + The character C following the open brace must be a space, tab, +newline, '(', or '|', and the close brace must be in a position where a +reserved word may appear (i.e., preceded by a command terminator such as +semicolon). Bash allows the close brace to be joined to the remaining +characters in the word without being followed by a shell metacharacter +as a reserved word would usually require. + + This type of command substitution superficially resembles executing +an unnamed shell function: local variables are created as when a shell +function is executing, and the 'return' builtin forces COMMAND to +complete; however, the rest of the execution environment, including the +positional parameters, is shared with the caller. + + If the first character following the open brace is a '(', COMMAND is +executed in a subshell, and COMMAND must be terminated by a ')'. This +is similar to the '(' compound command (*note Command Grouping::). If +the first character is a '|', the construct expands to the value of the +'REPLY' shell variable after COMMAND executes, without removing any +trailing newlines, and the standard output of COMMAND remains the same +as in the calling shell. Bash creates 'REPLY' as an initially-unset +local variable when COMMAND executes, and restores 'REPLY' to the value +it had before the command substitution after COMMAND completes, as with +any local variable. + + For example, this construct expands to '12345', and leaves the shell +variable 'X' unchanged in the current execution environment: + + ${ local X=12345 ; echo $X; } + +(not declaring 'X' as local would modify its value in the current +environment, as with normal shell function execution), while this +construct does not require any output to expand to '12345': + + ${| REPLY=12345; } + +and restores 'REPLY' to the value it had before the command +substitution. + 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 -filename expansion are not performed on the results. + If the substitution appears within double quotes, Bash does not +perform word splitting and filename expansion on the results. File: bash.info, Node: Arithmetic Expansion, Next: Process Substitution, Prev: Command Substitution, Up: Shell Expansions @@ -12706,138 +12753,138 @@ D.5 Concept Index Tag Table: -Node: Top888 -Node: Introduction2799 -Node: What is Bash?3012 -Node: What is a shell?4123 -Node: Definitions6658 -Node: Basic Shell Features9606 -Node: Shell Syntax10822 -Node: Shell Operation11845 -Node: Quoting13135 -Node: Escape Character14436 -Node: Single Quotes14918 -Node: Double Quotes15263 -Node: ANSI-C Quoting16538 -Node: Locale Translation17845 -Node: Creating Internationalized Scripts19153 -Node: Comments23267 -Node: Shell Commands23882 -Node: Reserved Words24817 -Node: Simple Commands25570 -Node: Pipelines26221 -Node: Lists29217 -Node: Compound Commands31009 -Node: Looping Constructs32018 -Node: Conditional Constructs34510 -Node: Command Grouping48995 -Node: Coprocesses50470 -Node: GNU Parallel53130 -Node: Shell Functions54044 -Node: Shell Parameters61926 -Node: Positional Parameters66311 -Node: Special Parameters67210 -Node: Shell Expansions70421 -Node: Brace Expansion72545 -Node: Tilde Expansion75276 -Node: Shell Parameter Expansion77894 -Node: Command Substitution96293 -Node: Arithmetic Expansion97645 -Node: Process Substitution98610 -Node: Word Splitting99727 -Node: Filename Expansion101772 -Node: Pattern Matching104702 -Node: Quote Removal109701 -Node: Redirections109993 -Node: Executing Commands119683 -Node: Simple Command Expansion120350 -Node: Command Search and Execution122457 -Node: Command Execution Environment124841 -Node: Environment127873 -Node: Exit Status129533 -Node: Signals131314 -Node: Shell Scripts134760 -Node: Shell Builtin Commands137784 -Node: Bourne Shell Builtins139819 -Node: Bash Builtins162015 -Node: Modifying Shell Behavior194011 -Node: The Set Builtin194353 -Node: The Shopt Builtin204948 -Node: Special Builtins220857 -Node: Shell Variables221833 -Node: Bourne Shell Variables222267 -Node: Bash Variables224368 -Node: Bash Features258430 -Node: Invoking Bash259440 -Node: Bash Startup Files265450 -Node: Interactive Shells270578 -Node: What is an Interactive Shell?270986 -Node: Is this Shell Interactive?271632 -Node: Interactive Shell Behavior272444 -Node: Bash Conditional Expressions276070 -Node: Shell Arithmetic280709 -Node: Aliases283667 -Node: Arrays286558 -Node: The Directory Stack293118 -Node: Directory Stack Builtins293899 -Node: Controlling the Prompt298156 -Node: The Restricted Shell301118 -Node: Bash POSIX Mode303725 -Node: Shell Compatibility Mode319515 -Node: Job Control327756 -Node: Job Control Basics328213 -Node: Job Control Builtins333212 -Node: Job Control Variables339004 -Node: Command Line Editing340157 -Node: Introduction and Notation341825 -Node: Readline Interaction343445 -Node: Readline Bare Essentials344633 -Node: Readline Movement Commands346419 -Node: Readline Killing Commands347376 -Node: Readline Arguments349294 -Node: Searching350335 -Node: Readline Init File352518 -Node: Readline Init File Syntax353776 -Node: Conditional Init Constructs377564 -Node: Sample Init File381757 -Node: Bindable Readline Commands384878 -Node: Commands For Moving386079 -Node: Commands For History388127 -Node: Commands For Text393118 -Node: Commands For Killing396764 -Node: Numeric Arguments399794 -Node: Commands For Completion400930 -Node: Keyboard Macros405118 -Node: Miscellaneous Commands405803 -Node: Readline vi Mode411838 -Node: Programmable Completion412742 -Node: Programmable Completion Builtins420519 -Node: A Programmable Completion Example431504 -Node: Using History Interactively436749 -Node: Bash History Facilities437430 -Node: Bash History Builtins440432 -Node: History Interaction445453 -Node: Event Designators449070 -Node: Word Designators450421 -Node: Modifiers452178 -Node: Installing Bash453983 -Node: Basic Installation455117 -Node: Compilers and Options458836 -Node: Compiling For Multiple Architectures459574 -Node: Installation Names461263 -Node: Specifying the System Type463369 -Node: Sharing Defaults464083 -Node: Operation Controls464753 -Node: Optional Features465708 -Node: Reporting Bugs476924 -Node: Major Differences From The Bourne Shell478255 -Node: GNU Free Documentation License495101 -Node: Indexes520275 -Node: Builtin Index520726 -Node: Reserved Word Index527550 -Node: Variable Index529995 -Node: Function Index546980 -Node: Concept Index560761 +Node: Top884 +Node: Introduction2791 +Node: What is Bash?3004 +Node: What is a shell?4115 +Node: Definitions6650 +Node: Basic Shell Features9598 +Node: Shell Syntax10814 +Node: Shell Operation11837 +Node: Quoting13127 +Node: Escape Character14428 +Node: Single Quotes14910 +Node: Double Quotes15255 +Node: ANSI-C Quoting16530 +Node: Locale Translation17839 +Node: Creating Internationalized Scripts19147 +Node: Comments23261 +Node: Shell Commands23876 +Node: Reserved Words24811 +Node: Simple Commands25564 +Node: Pipelines26215 +Node: Lists29211 +Node: Compound Commands31003 +Node: Looping Constructs32012 +Node: Conditional Constructs34504 +Node: Command Grouping48989 +Node: Coprocesses50464 +Node: GNU Parallel53124 +Node: Shell Functions54038 +Node: Shell Parameters61920 +Node: Positional Parameters66305 +Node: Special Parameters67204 +Node: Shell Expansions70415 +Node: Brace Expansion72539 +Node: Tilde Expansion75270 +Node: Shell Parameter Expansion77888 +Node: Command Substitution96287 +Node: Arithmetic Expansion99876 +Node: Process Substitution100841 +Node: Word Splitting101958 +Node: Filename Expansion104003 +Node: Pattern Matching106933 +Node: Quote Removal111932 +Node: Redirections112224 +Node: Executing Commands121914 +Node: Simple Command Expansion122581 +Node: Command Search and Execution124688 +Node: Command Execution Environment127072 +Node: Environment130104 +Node: Exit Status131764 +Node: Signals133545 +Node: Shell Scripts136991 +Node: Shell Builtin Commands140015 +Node: Bourne Shell Builtins142050 +Node: Bash Builtins164246 +Node: Modifying Shell Behavior196242 +Node: The Set Builtin196584 +Node: The Shopt Builtin207179 +Node: Special Builtins223088 +Node: Shell Variables224064 +Node: Bourne Shell Variables224498 +Node: Bash Variables226599 +Node: Bash Features260661 +Node: Invoking Bash261671 +Node: Bash Startup Files267681 +Node: Interactive Shells272809 +Node: What is an Interactive Shell?273217 +Node: Is this Shell Interactive?273863 +Node: Interactive Shell Behavior274675 +Node: Bash Conditional Expressions278301 +Node: Shell Arithmetic282940 +Node: Aliases285898 +Node: Arrays288789 +Node: The Directory Stack295349 +Node: Directory Stack Builtins296130 +Node: Controlling the Prompt300387 +Node: The Restricted Shell303349 +Node: Bash POSIX Mode305956 +Node: Shell Compatibility Mode321746 +Node: Job Control329987 +Node: Job Control Basics330444 +Node: Job Control Builtins335443 +Node: Job Control Variables341235 +Node: Command Line Editing342388 +Node: Introduction and Notation344056 +Node: Readline Interaction345676 +Node: Readline Bare Essentials346864 +Node: Readline Movement Commands348650 +Node: Readline Killing Commands349607 +Node: Readline Arguments351525 +Node: Searching352566 +Node: Readline Init File354749 +Node: Readline Init File Syntax356007 +Node: Conditional Init Constructs379795 +Node: Sample Init File383988 +Node: Bindable Readline Commands387109 +Node: Commands For Moving388310 +Node: Commands For History390358 +Node: Commands For Text395349 +Node: Commands For Killing398995 +Node: Numeric Arguments402025 +Node: Commands For Completion403161 +Node: Keyboard Macros407349 +Node: Miscellaneous Commands408034 +Node: Readline vi Mode414069 +Node: Programmable Completion414973 +Node: Programmable Completion Builtins422750 +Node: A Programmable Completion Example433735 +Node: Using History Interactively438980 +Node: Bash History Facilities439661 +Node: Bash History Builtins442663 +Node: History Interaction447684 +Node: Event Designators451301 +Node: Word Designators452652 +Node: Modifiers454409 +Node: Installing Bash456214 +Node: Basic Installation457348 +Node: Compilers and Options461067 +Node: Compiling For Multiple Architectures461805 +Node: Installation Names463494 +Node: Specifying the System Type465600 +Node: Sharing Defaults466314 +Node: Operation Controls466984 +Node: Optional Features467939 +Node: Reporting Bugs479155 +Node: Major Differences From The Bourne Shell480486 +Node: GNU Free Documentation License497332 +Node: Indexes522506 +Node: Builtin Index522957 +Node: Reserved Word Index529781 +Node: Variable Index532226 +Node: Function Index549211 +Node: Concept Index562992 End Tag Table |