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diff --git a/doc/bashref.html b/doc/bashref.html index 8c2eabf0..f494f344 100644 --- a/doc/bashref.html +++ b/doc/bashref.html @@ -1,13 +1,13 @@ <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- This text is a brief description of the features that are present in -the Bash shell (version 4.4, 7 September 2016). +the Bash shell (version 5.0, 15 March 2018). -This is Edition 4.4, last updated 7 September 2016, +This is Edition 5.0, last updated 15 March 2018, of The GNU Bash Reference Manual, -for Bash, Version 4.4. +for Bash, Version 5.0. -Copyright (C) 1988-2016 Free Software Foundation, Inc. +Copyright (C) 1988-2018 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or @@ -15,8 +15,9 @@ any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". --> -<!-- Created by GNU Texinfo 6.1, http://www.gnu.org/software/texinfo/ --> +<!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ --> <head> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Bash Reference Manual</title> <meta name="description" content="Bash Reference Manual"> @@ -24,7 +25,6 @@ A copy of the license is included in the section entitled <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="makeinfo"> -<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <link href="#Top" rel="start" title="Top"> <link href="#Indexes" rel="index" title="Indexes"> <link href="#SEC_Contents" rel="contents" title="Table of Contents"> @@ -284,12 +284,12 @@ Next: <a href="#Introduction" accesskey="n" rel="next">Introduction</a>, Previou <h1 class="top">Bash Features</h1> <p>This text is a brief description of the features that are present in -the Bash shell (version 4.4, 7 September 2016). +the Bash shell (version 5.0, 15 March 2018). The Bash home page is <a href="http://www.gnu.org/software/bash/">http://www.gnu.org/software/bash/</a>. </p> -<p>This is Edition 4.4, last updated 7 September 2016, +<p>This is Edition 5.0, last updated 15 March 2018, of <cite>The GNU Bash Reference Manual</cite>, -for <code>Bash</code>, Version 4.4. +for <code>Bash</code>, Version 5.0. </p> <p>Bash contains features that appear in other popular shells, and some features that only appear in Bash. Some of the shells that Bash has @@ -861,7 +861,7 @@ present, are decoded as follows: </p></dd> <dt><code>\<var>nnn</var></code></dt> <dd><p>the eight-bit character whose value is the octal value <var>nnn</var> -(one to three digits) +(one to three octal digits) </p></dd> <dt><code>\x<var>HH</var></code></dt> <dd><p>the eight-bit character whose value is the hexadecimal value <var>HH</var> @@ -1051,8 +1051,13 @@ the time information. <p>If the pipeline is not executed asynchronously (see <a href="#Lists">Lists</a>), the shell waits for all commands in the pipeline to complete. </p> -<p>Each command in a pipeline is executed in its own subshell -(see <a href="#Command-Execution-Environment">Command Execution Environment</a>). The exit +<p>Each command in a pipeline is executed in its own subshell, which is a +separate process (see <a href="#Command-Execution-Environment">Command Execution Environment</a>). +If the <code>lastpipe</code> option is enabled using the <code>shopt</code> builtin +(see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>), +the last element of a pipeline may be run by the shell process. +</p> +<p>The exit status of a pipeline is the exit status of the last command in the pipeline, unless the <code>pipefail</code> option is enabled (see <a href="#The-Set-Builtin">The Set Builtin</a>). @@ -1111,7 +1116,7 @@ associativity. </pre></div> <p><var>command2</var> is executed if, and only if, <var>command1</var> -returns an exit status of zero. +returns an exit status of zero (success). </p> <p>An <small>OR</small> list has the form </p><div class="example"> @@ -1144,7 +1149,7 @@ Next: <a href="#Coprocesses" accesskey="n" rel="next">Coprocesses</a>, Previous: </td></tr> </table> -<p>Compound commands are the shell programming constructs. +<p>Compound commands are the shell programming language constructs. Each construct begins with a reserved word or control operator and is terminated by a corresponding reserved word or operator. Any redirections (see <a href="#Redirections">Redirections</a>) associated with a compound command @@ -1211,13 +1216,15 @@ in <var>consequent-commands</var>, or zero if none was executed. <pre class="example">for <var>name</var> [ [in [<var>words</var> …] ] ; ] do <var>commands</var>; done </pre></div> -<p>Expand <var>words</var>, and execute <var>commands</var> once for each member +<p>Expand <var>words</var> (see <a href="#Shell-Expansions">Shell Expansions</a>), and execute <var>commands</var> +once for each member in the resultant list, with <var>name</var> bound to the current member. If ‘<samp>in <var>words</var></samp>’ is not present, the <code>for</code> command executes the <var>commands</var> once for each positional parameter that is set, as if ‘<samp>in "$@"</samp>’ had been specified (see <a href="#Special-Parameters">Special Parameters</a>). -The return status is the exit status of the last command that executes. +</p> +<p>The return status is the exit status of the last command that executes. If there are no items in the expansion of <var>words</var>, no commands are executed, and the return status is zero. </p> @@ -1295,6 +1302,8 @@ zero if no condition tested true. <p><code>case</code> will selectively execute the <var>command-list</var> corresponding to the first <var>pattern</var> that matches <var>word</var>. +The match is performed according +to the rules described below in <a href="#Pattern-Matching">Pattern Matching</a>. If the <code>nocasematch</code> shell option (see the description of <code>shopt</code> in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>) is enabled, the match is performed without regard to the case @@ -1306,7 +1315,9 @@ as a <var>clause</var>. </p> <p>Each clause must be terminated with ‘<samp>;;</samp>’, ‘<samp>;&</samp>’, or ‘<samp>;;&</samp>’. The <var>word</var> undergoes tilde expansion, parameter expansion, command -substitution, arithmetic expansion, and quote removal before matching is +substitution, arithmetic expansion, and quote removal +(see <a href="#Shell-Parameter-Expansion">Shell Parameter Expansion</a>) +before matching is attempted. Each <var>pattern</var> undergoes tilde expansion, parameter expansion, command substitution, and arithmetic expansion. </p> @@ -1467,7 +1478,7 @@ if there is a sequence of characters in the value consisting of any number, including zero, of space characters, zero or one instances of ‘<samp>a</samp>’, then a ‘<samp>b</samp>’: </p><div class="example"> -<pre class="example">[[ $line =~ [[:space:]]*(a)?b ]] +<pre class="example">[[ $line =~ [[:space:]]*?(a)b ]] </pre></div> <p>That means values like ‘<samp>aab</samp>’ and ‘<samp> aaaaaab</samp>’ will match, as @@ -1482,7 +1493,7 @@ expressions while paying attention to the shell’s quote removal. Using a shell variable to store the pattern decreases these problems. For example, the following is equivalent to the above: </p><div class="example"> -<pre class="example">pattern='[[:space:]]*(a)?b' +<pre class="example">pattern='[[:space:]]*?(a)b' [[ $line =~ $pattern ]] </pre></div> @@ -1633,7 +1644,8 @@ This pipe is established before any redirections specified by the command (see <a href="#Redirections">Redirections</a>). The file descriptors can be utilized as arguments to shell commands and redirections using standard word expansions. -The file descriptors are not available in subshells. +Other than those created to execute command and process substitutions, +the file descriptors are not available in subshells. </p> <p>The process ID of the shell spawned to execute the coprocess is available as the value of the variable <code>NAME</code>_PID. @@ -1744,7 +1756,7 @@ Adding the <samp>-k</samp> option <p>Finally, Parallel can be used to run a sequence of shell commands in parallel, similar to ‘<samp>cat file | bash</samp>’. It is not uncommon to take a list of filenames, create a series of shell -commands to operate on them, and feed that list of commnds to a shell. +commands to operate on them, and feed that list of commands to a shell. Parallel can speed this up. Assuming that <samp>file</samp> contains a list of shell commands, one per line, </p> @@ -1865,7 +1877,66 @@ before the <code>return</code>. </p> <p>Variables local to the function may be declared with the <code>local</code> builtin. These variables are visible only to -the function and the commands it invokes. +the function and the commands it invokes. This is particularly +important when a shell function calls other functions. +</p> +<p>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. +</p> +<p>The shell uses <var>dynamic scoping</var> 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 execution +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. +</p> +<p>For example, if a variable <var>var</var> is declared as local in function +<var>func1</var>, and <var>func1</var> calls another function <var>func2</var>, +references to <var>var</var> made from within <var>func2</var> will resolve to the +local variable <var>var</var> from <var>func1</var>, shadowing any global variable +named <var>var</var>. +</p> +<p>The following script demonstrates this behavior. +When executed, the script displays +</p> +<div class="example"> +<pre class="example">In func2, var = func1 local +</pre></div> + +<div class="example"> +<pre class="example">func1() +{ + local var='func1 local' + func2 +} + +func2() +{ + echo "In func2, var = $var" +} + +var=global +func1 +</pre></div> + +<p>The <code>unset</code> builtin also acts using the same dynamic scope: if a +variable is local to the current scope, <code>unset</code> will unset it; +otherwise the unset will refer to the variable found in any calling scope +as described above. +If a variable at the current local scope is unset, it will remain so +until it is reset in that scope or until the function returns. +Once the function returns, any instance of the variable at a previous +scope will become visible. +If the unset acts on a variable at a previous scope, any instance of a +variable with that name that had been shadowed will become visible. </p> <p>Function names and definitions may be listed with the <samp>-f</samp> option to the <code>declare</code> (<code>typeset</code>) @@ -1878,10 +1949,6 @@ Functions may be exported so that subshells automatically have them defined with the <samp>-f</samp> option to the <code>export</code> builtin (see <a href="#Bourne-Shell-Builtins">Bourne Shell Builtins</a>). -Note that shell functions and variables with the same name may result -in multiple identically-named entries in the environment passed to the -shell’s children. -Care should be taken in cases where this may cause a problem. </p> <p>Functions may be recursive. The <code>FUNCNEST</code> variable may be used to limit the depth of the @@ -2208,10 +2275,11 @@ original word are removed unless they have been quoted themselves (<var>quote removal</var>). </p> <p>Only brace expansion, word splitting, and filename expansion -can change the number of words of the expansion; other expansions +can increase the number of words of the expansion; other expansions expand a single word to a single word. The only exceptions to this are the expansions of -<code>"$@"</code> (see <a href="#Special-Parameters">Special Parameters</a>) and <code>"${<var>name</var>[@]}"</code> +<code>"$@"</code> and <code>$*</code> (see <a href="#Special-Parameters">Special Parameters</a>), and +<code>"${<var>name</var>[@]}"</code> and <code>${<var>name</var>[*]}</code> (see <a href="#Arrays">Arrays</a>). </p> <p>After all expansions, <code>quote removal</code> (see <a href="#Quote-Removal">Quote Removal</a>) @@ -2271,8 +2339,6 @@ and any characters special to other expansions are preserved in the result. It is strictly textual. Bash does not apply any syntactic interpretation to the context of the expansion or the text between the braces. -To avoid conflicts with parameter expansion, the string ‘<samp>${</samp>’ -is not considered eligible for brace expansion. </p> <p>A correctly-formed brace expansion must contain unquoted opening and closing braces, and at least one unquoted comma or a valid @@ -2282,7 +2348,8 @@ Any incorrectly formed brace expansion is left unchanged. <p>A { or ‘<samp>,</samp>’ may be quoted with a backslash to prevent its being considered part of a brace expression. To avoid conflicts with parameter expansion, the string ‘<samp>${</samp>’ -is not considered eligible for brace expansion. +is not considered eligible for brace expansion, +and inhibits brace expansion until the closing ‘<samp>}</samp>’.. </p> <p>This construct is typically used as shorthand when the common prefix of the strings to be generated is longer than in the @@ -2419,6 +2486,8 @@ Bash uses the value of the variable formed from the rest of expanded and that value is used in the rest of the substitution, rather than the value of <var>parameter</var> itself. This is known as <code>indirect expansion</code>. +The value is subject to tilde expansion, +parameter expansion, command substitution, and arithmetic expansion. If <var>parameter</var> is a nameref, this expands to the name of the variable referenced by <var>parameter</var> instead of performing the complete indirect expansion. @@ -2647,8 +2716,8 @@ array, and an index of -1 references the last element. <dt><code>${<var>parameter</var>#<var>word</var>}</code></dt> <dt><code>${<var>parameter</var>##<var>word</var>}</code></dt> <dd><p>The <var>word</var> -is expanded to produce a pattern just as in filename -expansion (see <a href="#Filename-Expansion">Filename Expansion</a>). If the pattern matches +is expanded to produce a pattern and matched according to the rules +described below (see <a href="#Pattern-Matching">Pattern Matching</a>). If the pattern matches the beginning of the expanded value of <var>parameter</var>, then the result of the expansion is the expanded value of <var>parameter</var> with the shortest matching pattern (the ‘<samp>#</samp>’ case) or the @@ -2664,8 +2733,9 @@ array in turn, and the expansion is the resultant list. </dd> <dt><code>${<var>parameter</var>%<var>word</var>}</code></dt> <dt><code>${<var>parameter</var>%%<var>word</var>}</code></dt> -<dd><p>The <var>word</var> is expanded to produce a pattern just as in -filename expansion. +<dd><p>The <var>word</var> +is expanded to produce a pattern and matched according to the rules +described below (see <a href="#Pattern-Matching">Pattern Matching</a>). If the pattern matches If the pattern matches a trailing portion of the expanded value of <var>parameter</var>, then the result of the expansion is the value of <var>parameter</var> with the shortest matching pattern (the ‘<samp>%</samp>’ case) @@ -2685,6 +2755,8 @@ array in turn, and the expansion is the resultant list. filename expansion. <var>Parameter</var> is expanded and the longest match of <var>pattern</var> against its value is replaced with <var>string</var>. +The match is performed according to the rules described below +(see <a href="#Pattern-Matching">Pattern Matching</a>). If <var>pattern</var> begins with ‘<samp>/</samp>’, all matches of <var>pattern</var> are replaced with <var>string</var>. Normally only the first match is replaced. If <var>pattern</var> begins with ‘<samp>#</samp>’, it must match at the beginning @@ -2745,7 +2817,7 @@ format that can be reused as input. </p></dd> <dt><code>E</code></dt> <dd><p>The expansion is a string that is the value of <var>parameter</var> with backslash -escape sequences expanded as with the <code>$'…'</code> quoting mechansim. +escape sequences expanded as with the <code>$'…'</code> quoting mechanism. </p></dd> <dt><code>P</code></dt> <dd><p>The expansion is a string that is the result of expanding the value of @@ -2974,18 +3046,23 @@ without regard to the case of alphabetic characters. <p>When a pattern is used for filename expansion, the character ‘<samp>.</samp>’ at the start of a filename or immediately following a slash must be matched explicitly, unless the shell option <code>dotglob</code> is set. -When matching a filename, the slash character must always be -matched explicitly. +The filenames ‘<samp>.</samp>’ and ‘<samp>..</samp>’ must always be matched explicitly, +even if <code>dotglob</code> is set. In other cases, the ‘<samp>.</samp>’ character is not treated specially. </p> +<p>When matching a filename, 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 (see <a href="#Pattern-Matching">Pattern Matching</a>). +</p> <p>See the description of <code>shopt</code> in <a href="#The-Shopt-Builtin">The Shopt Builtin</a>, for a description of the <code>nocaseglob</code>, <code>nullglob</code>, <code>failglob</code>, and <code>dotglob</code> options. </p> <p>The <code>GLOBIGNORE</code> -shell variable may be used to restrict the set of filenames matching a +shell variable may be used to restrict the set of file names matching a pattern. If <code>GLOBIGNORE</code> -is set, each matching filename that also matches one of the patterns in +is set, each matching file name that also matches one of the patterns in <code>GLOBIGNORE</code> is removed from the list of matches. If the <code>nocaseglob</code> option is set, the matching against the patterns in <code>GLOBIGNORE</code> is performed without regard to case. @@ -3110,6 +3187,12 @@ sub-patterns: </p></dd> </dl> +<p>Complicated extended pattern matching against long strings is slow, +especially when the patterns contain alternations and the strings +contain multiple matches. +Using separate matches against shorter strings, or using arrays of +strings instead of a single long string, may be faster. +</p> <hr> <a name="Quote-Removal"></a> <div class="header"> @@ -3154,6 +3237,9 @@ In this case, for each redirection operator except than 10 and assign it to {<var>varname</var>}. If >&- or <&- is preceded by {<var>varname</var>}, the value of <var>varname</var> defines the file descriptor to close. +If {<var>varname</var>} is supplied, the redirection persists beyond +the scope of the command, allowing the shell programmer to manage +the file descriptor himself. </p> <p>In the following descriptions, if the file descriptor number is omitted, and the first character of the redirection operator is @@ -3358,7 +3444,7 @@ natural fashion. </pre></div> <p>The <var>word</var> undergoes -brace expansion, tilde expansion, parameter and variable expansion, +tilde expansion, parameter and variable expansion, command substitution, arithmetic expansion, and quote removal. Pathname expansion and word splitting are not performed. The result is supplied as a single string, @@ -3534,9 +3620,10 @@ A full search of the directories in <code>$PATH</code> is performed only if the command is not found in the hash table. If the search is unsuccessful, the shell searches for a defined shell function named <code>command_not_found_handle</code>. -If that function exists, it is invoked with the original command and +If that function exists, it is invoked 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 the shell. +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 status of 127. @@ -3894,7 +3981,7 @@ facilities (see <a href="#Programmable-Completion-Builtins">Programmable Complet <p>Unless otherwise noted, each builtin command documented as accepting options preceded by ‘<samp>-</samp>’ accepts ‘<samp>--</samp>’ to signify the end of the options. -The <code>:</code>, <code>true</code>, <code>false</code>, and <code>test</code> +The <code>:</code>, <code>true</code>, <code>false</code>, and <code>test</code>/<code>[</code> builtins do not accept options and do not treat ‘<samp>--</samp>’ specially. The <code>exit</code>, <code>logout</code>, <code>return</code>, <code>break</code>, <code>continue</code>, <code>let</code>, @@ -4061,6 +4148,7 @@ cannot be executed for some reason, a non-interactive shell exits, unless the <code>execfail</code> shell option is enabled. In that case, it returns failure. An interactive shell returns failure if the file cannot be executed. +A subshell exits unconditionally if <code>exec</code> fails. If no <var>command</var> is specified, redirections may be used to affect the current shell environment. If there are no redirection errors, the return status is zero; otherwise the return status is non-zero. @@ -4173,7 +4261,7 @@ The <samp>-d</samp> option causes the shell to forget the remembered location of each <var>name</var>. If the <samp>-t</samp> option is supplied, the full pathname to which each <var>name</var> corresponds is printed. If multiple <var>name</var> arguments are -supplied with <samp>-t</samp> the <var>name</var> is printed before the hashed +supplied with <samp>-t</samp>, the <var>name</var> is printed before the hashed full pathname. The <samp>-l</samp> option causes output to be displayed in a format that may be reused as input. @@ -4238,7 +4326,7 @@ If <var>n</var> is not supplied, the return value is the exit status of the last command executed in the function. If <code>return</code> is executed by a trap handler, the last command used to determine the status is the last command executed before the trap handler. -if <code>return</code> is executed during a <code>DEBUG</code> trap, the last command +If <code>return</code> is executed during a <code>DEBUG</code> trap, the last command used to determine the status is the last command executed by the trap handler before <code>return</code> was invoked. <code>return</code> may also be used to terminate execution of a script @@ -4326,7 +4414,7 @@ expressions using a set of rules based on the number of arguments. </p> </dd> <dt>1 argument</dt> -<dd><p>The expression is true if and only if the argument is not null. +<dd><p>The expression is true if, and only if, the argument is not null. </p> </dd> <dt>2 arguments</dt> @@ -5004,6 +5092,8 @@ Options, if supplied, have the following meanings: <dt><code>-d</code></dt> <dd><p>The first character of <var>delim</var> is used to terminate each input line, rather than newline. +If <var>delim</var> is the empty string, <code>mapfile</code> will terminate a line +when it reads a NUL character. </p></dd> <dt><code>-n</code></dt> <dd><p>Copy at most <var>count</var> lines. If <var>count</var> is 0, all lines are copied. @@ -5022,7 +5112,7 @@ The default index is 0. <dd><p>Read lines from file descriptor <var>fd</var> instead of the standard input. </p></dd> <dt><code>-C</code></dt> -<dd><p>Evaluate <var>callback</var> each time <var>quantum</var>P lines are read. +<dd><p>Evaluate <var>callback</var> each time <var>quantum</var> lines are read. The <samp>-c</samp> option specifies <var>quantum</var>. </p></dd> <dt><code>-c</code></dt> @@ -5142,12 +5232,14 @@ Other <var>name</var> arguments are ignored. <dt><code>-d <var>delim</var></code></dt> <dd><p>The first character of <var>delim</var> is used to terminate the input line, rather than newline. +If <var>delim</var> is the empty string, <code>read</code> will terminate a line +when it reads a NUL character. </p> </dd> <dt><code>-e</code></dt> <dd><p>Readline (see <a href="#Command-Line-Editing">Command Line Editing</a>) is used to obtain the line. Readline uses the current (or default, if line editing was not previously -active) editing settings. +active) editing settings, but uses Readline’s default filename completion. </p> </dd> <dt><code>-i <var>text</var></code></dt> @@ -5816,7 +5908,8 @@ The settings can be either those listed below, or, if the <samp>-o</samp> option is used, those available with the <samp>-o</samp> option to the <code>set</code> builtin command (see <a href="#The-Set-Builtin">The Set Builtin</a>). With no options, or with the <samp>-p</samp> option, a list of all settable -options is displayed, with an indication of whether or not each is set. +options is displayed, with an indication of whether or not each is set; +if <var>optnames</var> are supplied, the output is restricted to those options. The <samp>-p</samp> option causes output to be displayed in a form that may be reused as input. Other options have the following meanings: @@ -5859,6 +5952,12 @@ option. </p> <p>The list of <code>shopt</code> options is: </p><dl compact="compact"> +<dt><code>assoc_expand_once</code></dt> +<dd><p>If set, the shell suppresses multiple evaluation of associative array +subscripts during arithmetic expression evaluation and while executing +builtins that can perform variable assignments. +</p> +</dd> <dt><code>autocd</code></dt> <dd><p>If set, a command name that is the name of a directory is executed as if it were the argument to the <code>cd</code> command. @@ -5896,8 +5995,8 @@ The shell always postpones exiting if any jobs are stopped. </p> </dd> <dt><code>checkwinsize</code></dt> -<dd><p>If set, Bash checks the window size after each command - and, if necessary, updates the values of +<dd><p>If set, Bash checks the window size after each external (non-builtin) +command and, if necessary, updates the values of <code>LINES</code> and <code>COLUMNS</code>. </p> </dd> @@ -5906,6 +6005,8 @@ The shell always postpones exiting if any jobs are stopped. attempts to save all lines of a multiple-line command in the same history entry. This allows easy re-editing of multi-line commands. +This option is enabled by default, but only has an effect if command +history is enabled (see <a href="#Bash-History-Facilities">Bash History Facilities</a>). </p> </dd> <dt><code>compat31</code></dt> @@ -5966,6 +6067,12 @@ loop state when a shell function is executed (this allows <code>break</code> or <code>continue</code> in a shell function to affect loops in the caller’s context). </p> </dd> +<dt><code>compat44</code></dt> +<dd><p>If set, Bash +saves the positional parameters to BASH_ARGV and BASH_ARGC before they are +used, regardless of whether or not extended debugging mode is enabled. +</p> +</dd> <dt><code>complete_fullquote</code></dt> <dd><p>If set, Bash quotes all shell metacharacters in filenames and directory names when @@ -6001,6 +6108,8 @@ if the directory name initially supplied does not exist. <dt><code>dotglob</code></dt> <dd><p>If set, Bash includes filenames beginning with a ‘.’ in the results of filename expansion. +The filenames ‘<samp>.</samp>’ and ‘<samp>..</samp>’ must always be matched explicitly, +even if <code>dotglob</code> is set. </p> </dd> <dt><code>execfail</code></dt> @@ -6148,6 +6257,12 @@ option is enabled, multi-line commands are saved to the history with embedded newlines rather than using semicolon separators where possible. </p> </dd> +<dt><code>localvar_inherit</code></dt> +<dd><p>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 <var>nameref</var> attribute is not inherited. +</p> +</dd> <dt><code>login_shell</code></dt> <dd><p>The shell sets this option if it is started as a login shell (see <a href="#Invoking-Bash">Invoking Bash</a>). @@ -6378,6 +6493,8 @@ sequences that are expanded before <code>PS1</code> is displayed. <a name="index-PS2"></a> </dt> <dd><p>The secondary prompt string. The default value is ‘<samp>> </samp>’. +<code>PS2</code> is expanded in the same way as <code>PS1</code> before being +displayed. </p> </dd> </dl> @@ -6424,6 +6541,10 @@ reading any startup files. This variable is readonly. <dd><p>Expands to the process ID of the current Bash process. This differs from <code>$$</code> under certain circumstances, such as subshells that do not require Bash to be re-initialized. +Assignments to <code>BASHPID</code> have no effect. +If <code>BASHPID</code> +is unset, it loses its special properties, even if it is +subsequently reset. </p> </dd> <dt><code>BASH_ALIASES</code> @@ -6453,6 +6574,8 @@ The shell sets <code>BASH_ARGC</code> only when in extended debugging mode (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a> for a description of the <code>extdebug</code> option to the <code>shopt</code> builtin). +Setting <code>extdebug</code> after the shell has started to execute a script +may result in inconsistent values. </p> </dd> <dt><code>BASH_ARGV</code> @@ -6467,6 +6590,21 @@ The shell sets <code>BASH_ARGV</code> only when in extended debugging mode (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a> for a description of the <code>extdebug</code> option to the <code>shopt</code> builtin). +Setting <code>extdebug</code> after the shell has started to execute a script +may result in inconsistent values. +</p> +</dd> +<dt><code>BASH_ARGV0</code> +<a name="index-BASH_005fARGV0"></a> +</dt> +<dd><p>When referenced, this variable expands to the name of the shell or shell +script (identical to <code>$0</code>; See <a href="#Special-Parameters">Special Parameters</a>, +for the description of special parameter 0). +Assignment to <code>BASH_ARGV0</code> +causes the value assigned to also be assigned to <code>$0</code>. +If <code>BASH_ARGV0</code> +is unset, it loses its special properties, even if it is +subsequently reset. </p> </dd> <dt><code>BASH_CMDS</code> @@ -6770,6 +6908,29 @@ Emacs shell buffer and disables line editing. <small>POSIX</small> Mode (see <a href="#Bash-POSIX-Mode">Bash POSIX Mode</a>). </p> </dd> +<dt><code>EPOCHREALTIME</code> +<a name="index-EPOCHREALTIME"></a> +</dt> +<dd><p>Each time this parameter is referenced, it expands to the number of seconds +since the Unix Epoch as a floating point value with micro-second granularity +(see the documentation for the C library function <var>time</var> for the +definition of Epoch). +Assignments to <code>EPOCHREALTIME</code> are ignored. +If <code>EPOCHREALTIME</code> is unset, it loses its special properties, even if +it is subsequently reset. +</p> +</dd> +<dt><code>EPOCHSECONDS</code> +<a name="index-EPOCHSECONDS"></a> +</dt> +<dd><p>Each time this parameter is referenced, it expands to the number of seconds +since the Unix Epoch (see the documentation for the C library function +<var>time</var> for the definition of Epoch). +Assignments to <code>EPOCHSECONDS</code> are ignored. +If <code>EPOCHSECONDS</code> is unset, it loses its special properties, even if +it is subsequently reset. +</p> +</dd> <dt><code>EUID</code> <a name="index-EUID"></a> </dt> @@ -6847,9 +7008,9 @@ will cause the current command to abort. <dt><code>GLOBIGNORE</code> <a name="index-GLOBIGNORE"></a> </dt> -<dd><p>A colon-separated list of patterns defining the set of filenames to +<dd><p>A colon-separated list of patterns defining the set of file names to be ignored by filename expansion. -If a filename matched by a filename expansion pattern also matches one +If a file name matched by a filename expansion pattern also matches one of the patterns in <code>GLOBIGNORE</code>, it is removed from the list of matches. The pattern matching honors the setting of the <code>extglob</code> shell @@ -7208,10 +7369,11 @@ and before the command is executed. <dt><code>PS4</code> <a name="index-PS4"></a> </dt> -<dd><p>The value is the prompt printed before the command line is echoed -when the <samp>-x</samp> option is set (see <a href="#The-Set-Builtin">The Set Builtin</a>). -The first character of <code>PS4</code> is replicated multiple times, as -necessary, to indicate multiple levels of indirection. +<dd><p>The value of this parameter is expanded like <var>PS1</var> +and the expanded value is the prompt printed before the command line +is echoed when the <samp>-x</samp> option is set (see <a href="#The-Set-Builtin">The Set Builtin</a>). +The first character of the expanded value is replicated multiple times, +as necessary, to indicate multiple levels of indirection. The default is ‘<samp>+ </samp>’. </p> </dd> @@ -7544,7 +7706,8 @@ of a login shell. <dd><p>If this 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. +when invoking an interactive shell or when reading input +through a pipe. </p> </dd> <dt><code>-D</code></dt> @@ -7823,7 +7986,10 @@ signals <code>SIGTTIN</code>, <code>SIGTTOU</code>, and <code>SIGTSTP</code>. </li><li> Bash expands and displays <code>PS1</code> before reading the first line of a command, and expands and displays <code>PS2</code> before reading the second and subsequent lines of a multi-line command. -Bash displays <code>PS0</code> after it reads a command but before executing it. +Bash expands and displays <code>PS0</code> after it reads a command but before +executing it. +See <a href="#Controlling-the-Prompt">Controlling the Prompt</a>, for a complete list of prompt +string escape sequences. </li><li> Bash executes the value of the <code>PROMPT_COMMAND</code> variable as a command before printing the primary prompt, <code>$PS1</code> @@ -8076,6 +8242,8 @@ is equal to, not equal to, less than, less than or equal to, greater than, or greater than or equal to <var>arg2</var>, respectively. <var>Arg1</var> and <var>arg2</var> may be positive or negative integers. +When used with the <code>[[</code> command, <var>Arg1</var> and <var>Arg2</var> +are evaluated as arithmetic expressions (see <a href="#Shell-Arithmetic">Shell Arithmetic</a>). </p></dd> </dl> @@ -8396,12 +8564,16 @@ special parameters ‘<samp>@</samp>’ and ‘<samp>*</samp>’ <code>unset <var>name</var>[<var>subscript</var>]</code> destroys the array element at index <var>subscript</var>. Negative subscripts to indexed arrays are interpreted as described above. -Care must be taken to avoid unwanted side effects caused by filename -expansion. +Unsetting the last element of an array variable does not unset the variable. <code>unset <var>name</var></code>, where <var>name</var> is an array, removes the entire array. A subscript of ‘<samp>*</samp>’ or ‘<samp>@</samp>’ also removes the entire array. </p> +<p>When using a variable name with a subscript as an argument to a command, +such as with <code>unset</code>, without using the word expansion syntax +described above, the argument is subject to the shell’s filename expansion. +If filename expansion is not desired, the argument should be quoted. +</p> <p>The <code>declare</code>, <code>local</code>, and <code>readonly</code> builtins each accept a <samp>-a</samp> option to specify an indexed array and a <samp>-A</samp> option to specify an associative array. @@ -8569,7 +8741,8 @@ has a non-null value, then the value is executed just as if it had been typed on the command line. </p> <p>In addition, the following table describes the special characters which -can appear in the prompt variables <code>PS1</code> to <code>PS4</code>: +can appear in the prompt variables <code>PS0</code>, <code>PS1</code>, <code>PS2</code>, and +<code>PS4</code>: </p> <dl compact="compact"> <dt><code>\a</code></dt> @@ -9102,6 +9275,11 @@ The <code>jobs</code> command may then be used to inspect their status. If a second attempt to exit is made without an intervening command, Bash does not print another warning, and any stopped jobs are terminated. </p> +<p>When the shell is waiting for a job or process using the <code>wait</code> +builtin, and job control is enabled, <code>wait</code> will return when the +job changes state. The <samp>-f</samp> option will force <code>wait</code> to wait +until the job or process terminates before returning. +</p> <hr> <a name="Job-Control-Builtins"></a> <div class="header"> @@ -9212,7 +9390,7 @@ or non-zero if an error occurs or an invalid option is encountered. <dt><code>wait</code></dt> <dd><a name="index-wait"></a> <div class="example"> -<pre class="example">wait [-n] [<var>jobspec</var> or <var>pid</var> …] +<pre class="example">wait [-fn] [<var>jobspec</var> or <var>pid</var> …] </pre></div> <p>Wait until the child process specified by each process <small>ID</small> <var>pid</var> @@ -9223,6 +9401,9 @@ If no arguments are given, all currently active child processes are waited for, and the return status is zero. If the <samp>-n</samp> option is supplied, <code>wait</code> waits for any job to terminate and returns its exit status. +If the <samp>-f</samp> option is supplied, and job control is enabled, +<code>wait</code> forces each <var>pid</var> or <var>jobspec</var> to terminate before +returning its status, intead of returning when it changes status. If neither <var>jobspec</var> nor <var>pid</var> specifies an active child process of the shell, the return status is 127. </p> @@ -9879,7 +10060,8 @@ set to either ‘<samp>emacs</samp>’ or ‘<samp>vi</samp>’. </dd> <dt><code>emacs-mode-string</code></dt> <dd><a name="index-emacs_002dmode_002dstring"></a> -<p>This string is displayed immediately before the last line of the primary +<p>If the <var>show-mode-in-prompt</var> 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. @@ -10092,9 +10274,9 @@ The default value is ‘<samp>off</samp>’. </dd> <dt><code>show-mode-in-prompt</code></dt> <dd><a name="index-show_002dmode_002din_002dprompt"></a> -<p>If set to ‘<samp>on</samp>’, add a character to the beginning of the prompt +<p>If set to ‘<samp>on</samp>’, add a string to the beginning of the prompt indicating the editing mode: emacs, vi command, or vi insertion. -The mode strings are user-settable. +The mode strings are user-settable (e.g., <var>emacs-mode-string</var>). The default value is ‘<samp>off</samp>’. </p> </dd> @@ -10115,7 +10297,8 @@ The default value is ‘<samp>off</samp>’. </dd> <dt><code>vi-cmd-mode-string</code></dt> <dd><a name="index-vi_002dcmd_002dmode_002dstring"></a> -<p>This string is displayed immediately before the last line of the primary +<p>If the <var>show-mode-in-prompt</var> 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 @@ -10128,7 +10311,8 @@ The default is ‘<samp>(cmd)</samp>’. </dd> <dt><code>vi-ins-mode-string</code></dt> <dd><a name="index-vi_002dins_002dmode_002dstring"></a> -<p>This string is displayed immediately before the last line of the primary +<p>If the <var>show-mode-in-prompt</var> 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 @@ -10321,8 +10505,9 @@ of tests. There are four parser directives used. <dt><code>$if</code></dt> <dd><p>The <code>$if</code> construct allows bindings to be made based on the editing 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. +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. </p> <dl compact="compact"> <dt><code>mode</code></dt> @@ -10344,6 +10529,28 @@ allows <code>sun</code> to match both <code>sun</code> and <code>sun-cmd</code>, for instance. </p> </dd> +<dt><code>version</code></dt> +<dd><p>The <code>version</code> test may be used to perform comparisons against +specific Readline versions. +The <code>version</code> expands to the current Readline version. +The set of comparison operators includes +‘<samp>=</samp>’ (and ‘<samp>==</samp>’), ‘<samp>!=</samp>’, ‘<samp><=</samp>’, ‘<samp>>=</samp>’, ‘<samp><</samp>’, +and ‘<samp>></samp>’. +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., ‘<samp>7.1</samp>’). If the minor version is omitted, it +is assumed to be ‘<samp>0</samp>’. +The operator may be separated from the string <code>version</code> and +from the version number argument by whitespace. +The following example sets a variable if the Readline version being used +is 7.0 or newer: +</p><div class="example"> +<pre class="example">$if version >= 7.0 +set show-mode-in-prompt on +$endif +</pre></div> + +</dd> <dt><code>application</code></dt> <dd><p>The <var>application</var> construct is used to include application-specific settings. Each program using the Readline @@ -10358,6 +10565,24 @@ key sequence that quotes the current or previous word in Bash: "\C-xq": "\eb\"\ef\"" $endif </pre></div> + +</dd> +<dt><code>variable</code></dt> +<dd><p>The <var>variable</var> construct provides simple equality tests for Readline +variables and values. +The permitted comparison operators are ‘<samp>=</samp>’, ‘<samp>==</samp>’, and ‘<samp>!=</samp>’. +The variable name must be separated from the comparison operator by +whitespace; the operator may be separated from the value on the right hand +side by whitespace. +Both string and boolean variables may be tested. Boolean variables must be +tested against the values <var>on</var> and <var>off</var>. +The following example is equivalent to the <code>mode=emacs</code> test described +above: +</p><div class="example"> +<pre class="example">$if editing-mode == emacs +set show-mode-in-prompt on +$endif +</pre></div> </dd> </dl> @@ -10597,6 +10822,25 @@ Words are delimited by non-quoted shell metacharacters. Words are delimited by non-quoted shell metacharacters. </p> </dd> +<dt><code>previous-screen-line ()</code> +<a name="index-previous_002dscreen_002dline-_0028_0029"></a> +</dt> +<dd><p>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. +</p> +</dd> +<dt><code>next-screen-line ()</code> +<a name="index-next_002dscreen_002dline-_0028_0029"></a> +</dt> +<dd><p>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. +</p> +</dd> <dt><code>clear-screen (C-l)</code> <a name="index-clear_002dscreen-_0028C_002dl_0029"></a> </dt> @@ -10710,8 +10954,8 @@ This is a non-incremental search. By default, this command is unbound. </p> </dd> -<dt><code>history-substr-search-forward ()</code> -<a name="index-history_002dsubstr_002dsearch_002dforward-_0028_0029"></a> +<dt><code>history-substring-search-forward ()</code> +<a name="index-history_002dsubstring_002dsearch_002dforward-_0028_0029"></a> </dt> <dd><p>Search forward through the history for the string of characters between the start of the current line and the point. @@ -10720,8 +10964,8 @@ This is a non-incremental search. By default, this command is unbound. </p> </dd> -<dt><code>history-substr-search-backward ()</code> -<a name="index-history_002dsubstr_002dsearch_002dbackward-_0028_0029"></a> +<dt><code>history-substring-search-backward ()</code> +<a name="index-history_002dsubstring_002dsearch_002dbackward-_0028_0029"></a> </dt> <dd><p>Search backward through the history for the string of characters between the start of the current line and the point. @@ -11285,11 +11529,12 @@ ring the terminal’s bell (subject to the setting of <code>bell-style</code>). </p> </dd> -<dt><code>do-uppercase-version (M-a, M-b, M-<var>x</var>, …)</code> -<a name="index-do_002duppercase_002dversion-_0028M_002da_002c-M_002db_002c-M_002dx_002c-_2026_0029"></a> +<dt><code>do-lowercase-version (M-A, M-B, M-<var>x</var>, …)</code> +<a name="index-do_002dlowercase_002dversion-_0028M_002dA_002c-M_002dB_002c-M_002dx_002c-_2026_0029"></a> </dt> -<dd><p>If the metafied character <var>x</var> is lowercase, run the command -that is bound to the corresponding uppercase character. +<dd><p>If the metafied character <var>x</var> is upper case, run the command +that is bound to the corresponding metafied lower case character. +The behavior is undefined if <var>x</var> is already lower case. </p> </dd> <dt><code>prefix-meta (<span class="key">ESC</span>)</code> @@ -11479,12 +11724,13 @@ word expansions (see <a href="#Shell-Expansions">Shell Expansions</a>). <a name="index-operate_002dand_002dget_002dnext-_0028C_002do_0029"></a> </dt> <dd><p>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. +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. </p> </dd> -<dt><code>edit-and-execute-command (C-xC-e)</code> -<a name="index-edit_002dand_002dexecute_002dcommand-_0028C_002dxC_002de_0029"></a> +<dt><code>edit-and-execute-command (C-x C-e)</code> +<a name="index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029"></a> </dt> <dd><p>Invoke an editor on the current command line, and execute the result as shell commands. @@ -11574,7 +11820,9 @@ but the <code>FIGNORE</code> shell variable is used. is considered. The string is first split using the characters in the <code>IFS</code> special variable as delimiters. -Shell quoting is honored. +Shell quoting is honored within the string, in order to provide a +mechanism for the words to contain shell metacharacters or characters +in the value of <code>IFS</code>. Each word is then expanded using brace expansion, tilde expansion, parameter and variable expansion, command substitution, and arithmetic expansion, @@ -12013,7 +12261,7 @@ a shell function and bind it to a particular command using <code>complete -F</co </p> <p>The following function provides completions for the <code>cd</code> builtin. It is a reasonably good example of what shell functions must do when -used for completion. This function uses the word passsed as <code>$2</code> +used for completion. This function uses the word passed as <code>$2</code> to determine the directory name to complete. You can also use the <code>COMP_WORDS</code> array variable; the current word is indexed by the <code>COMP_CWORD</code> variable. @@ -12220,7 +12468,7 @@ The <code>lithist</code> shell option causes the shell to save the command with embedded newlines instead of semicolons. The <code>shopt</code> builtin is used to set these options. -See <a href="#Bash-Builtins">Bash Builtins</a>, for a description of <code>shopt</code>. +See <a href="#The-Shopt-Builtin">The Shopt Builtin</a>, for a description of <code>shopt</code>. </p> <hr> <a name="Bash-History-Builtins"></a> @@ -12250,8 +12498,8 @@ Both <var>first</var> and <var>last</var> may be specified as a string (to locate the most recent 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 <var>last</var> is not specified it is set to -<var>first</var>. If <var>first</var> is not specified it is set to the previous +current command number). If <var>last</var> is not specified, it is set to +<var>first</var>. If <var>first</var> is not specified, it is set to the previous command for editing and -16 for listing. If the <samp>-l</samp> flag is given, the commands are listed on standard output. The <samp>-n</samp> flag suppresses the command numbers when listing. The <samp>-r</samp> flag @@ -12278,6 +12526,7 @@ and typing ‘<samp>r</samp>’ re-executes the last command (see <a hre <pre class="example">history [<var>n</var>] history -c history -d <var>offset</var> +history -d <var>start</var>-<var>end</var> history [-anrw] [<var>filename</var>] history -ps <var>arg</var> </pre></div> @@ -12301,8 +12550,18 @@ with the other options to replace the history list completely. </dd> <dt><code>-d <var>offset</var></code></dt> <dd><p>Delete the history entry at position <var>offset</var>. -<var>offset</var> should be specified as it appears when the history is -displayed. +If <var>offset</var> is positive, it should be specified as it appears when +the history is displayed. +If <var>offset</var> 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 ‘<samp>-1</samp>’ refers to the current +<code>history -d</code> command. +</p> +</dd> +<dt><code>-d <var>start</var>-<var>end</var></code></dt> +<dd><p>Delete the history entries between positions <var>start</var> and <var>end</var>, +inclusive. Positive and negative values for <var>start</var> and <var>end</var> +are interpreted as described above. </p> </dd> <dt><code>-a</code></dt> @@ -12366,7 +12625,9 @@ arguments to a previous command into the current input line, or fix errors in previous commands quickly. </p> <p>History expansion is performed immediately after a complete line -is read, before the shell breaks it into words. +is read, before the shell breaks it into words, and is performed +on each line individually without taking quoting on previous lines into +account. </p> <p>History expansion takes place in two parts. The first is to determine which line from the history list should be used during substitution. @@ -12385,7 +12646,7 @@ also treated as quoted if it immediately precedes the closing double quote in a double-quoted string. </p> <p>Several shell options settable with the <code>shopt</code> -builtin (see <a href="#Bash-Builtins">Bash Builtins</a>) may be used to tailor +builtin (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>) may be used to tailor the behavior of history expansion. If the <code>histverify</code> shell option is enabled, and Readline is being used, history substitutions are not immediately passed to @@ -12728,11 +12989,27 @@ may remove or edit it. <code>configure</code> script understands, type </p> <div class="example"> -<pre class="example">bash-2.04$ ./configure --help +<pre class="example">bash-4.2$ ./configure --help </pre></div> <p>at the Bash prompt in your Bash source directory. </p> +<p>If you want to build Bash in a directory separate from the source +directory – to build for multiple architectures, for example – +just use the full path to the configure script. The following commands +will build bash in a directory under <samp>/usr/local/build</samp> from +the source code in <samp>/usr/local/src/bash-4.4</samp>: +</p> +<div class="example"> +<pre class="example">mkdir /usr/local/build/bash-4.4 +cd /usr/local/build/bash-4.4 +bash /usr/local/src/bash-4.4/configure +make +</pre></div> + +<p>See <a href="#Compiling-For-Multiple-Architectures">Compiling For Multiple Architectures</a> for more information +about building in a directory separate from the source. +</p> <p>If you need to do unusual things to compile Bash, please try to figure out how <code>configure</code> could check whether or not to do them, and mail diffs or instructions to @@ -12794,7 +13071,9 @@ own directory. To do this, you must use a version of <code>make</code> that supports the <code>VPATH</code> variable, such as GNU <code>make</code>. <code>cd</code> to the directory where you want the object files and executables to go and run -the <code>configure</code> script from the source directory. You may need to +the <code>configure</code> script from the source directory +(see <a href="#Basic-Installation">Basic Installation</a>). +You may need to supply the <samp>--srcdir=PATH</samp> argument to tell <code>configure</code> where the source files are. <code>configure</code> automatically checks for the source code in the directory that <code>configure</code> is in and in ‘..’. @@ -13097,6 +13376,13 @@ This allows pipelines as well as shell builtins and functions to be timed. <dd><p>Include support for the bash debugger (distributed separately). </p> </dd> +<dt><code>--enable-dev-fd-stat-broken</code></dt> +<dd><p>If calling <code>stat</code> on /dev/fd/<var>N</var> returns different results than +calling <code>fstat</code> on file descriptor <var>N</var>, supply this option to +enable a workaround. +This has implications for conditional commands that test file attributes. +</p> +</dd> <dt><code>--enable-direxpand-default</code></dt> <dd><p>Cause the <code>direxpand</code> shell option (see <a href="#The-Shopt-Builtin">The Shopt Builtin</a>) to be enabled by default when the shell starts. @@ -13184,7 +13470,7 @@ If Readline is not enabled, this option has no effect. </dd> <dt><code>--enable-prompt-string-decoding</code></dt> <dd><p>Turn on the interpretation of a number of backslash-escaped characters -in the <code>$PS1</code>, <code>$PS2</code>, <code>$PS3</code>, and <code>$PS4</code> prompt +in the <code>$PS0</code>, <code>$PS1</code>, <code>$PS2</code>, and <code>$PS4</code> prompt strings. See <a href="#Controlling-the-Prompt">Controlling the Prompt</a>, for a complete list of prompt string escape sequences. </p> @@ -13692,7 +13978,7 @@ Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. </pre></div> -<ol> +<ol start="0"> <li> PREAMBLE <p>The purpose of this License is to make a manual, textbook, or other @@ -13868,7 +14154,7 @@ Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version: </p> -<ol> +<ol type="A" start="1"> <li> Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section @@ -14614,6 +14900,7 @@ Next: <a href="#Function-Index" accesskey="n" rel="next">Function Index</a>, Pre <tr><td></td><td valign="top"><a href="#index-BASH_005fALIASES"><code>BASH_ALIASES</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> <tr><td></td><td valign="top"><a href="#index-BASH_005fARGC"><code>BASH_ARGC</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> <tr><td></td><td valign="top"><a href="#index-BASH_005fARGV"><code>BASH_ARGV</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-BASH_005fARGV0"><code>BASH_ARGV0</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> <tr><td></td><td valign="top"><a href="#index-BASH_005fCMDS"><code>BASH_CMDS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> <tr><td></td><td valign="top"><a href="#index-BASH_005fCOMMAND"><code>BASH_COMMAND</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> <tr><td></td><td valign="top"><a href="#index-BASH_005fCOMPAT"><code>BASH_COMPAT</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> @@ -14666,6 +14953,8 @@ Next: <a href="#Function-Index" accesskey="n" rel="next">Function Index</a>, Pre <tr><td></td><td valign="top"><a href="#index-enable_002dbracketed_002dpaste"><code>enable-bracketed-paste</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr> <tr><td></td><td valign="top"><a href="#index-enable_002dkeypad"><code>enable-keypad</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr> <tr><td></td><td valign="top"><a href="#index-ENV"><code>ENV</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-EPOCHREALTIME"><code>EPOCHREALTIME</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-EPOCHSECONDS"><code>EPOCHSECONDS</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> <tr><td></td><td valign="top"><a href="#index-EUID"><code>EUID</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> <tr><td></td><td valign="top"><a href="#index-EXECIGNORE"><code>EXECIGNORE</code></a>:</td><td> </td><td valign="top"><a href="#Bash-Variables">Bash Variables</a></td></tr> <tr><td></td><td valign="top"><a href="#index-expand_002dtilde"><code>expand-tilde</code></a>:</td><td> </td><td valign="top"><a href="#Readline-Init-File-Syntax">Readline Init File Syntax</a></td></tr> @@ -14937,7 +15226,7 @@ Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previ <tr><td></td><td valign="top"><a href="#index-delete_002dhorizontal_002dspace-_0028_0029"><code>delete-horizontal-space ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Killing">Commands For Killing</a></td></tr> <tr><td></td><td valign="top"><a href="#index-digit_002dargument-_0028M_002d0_002c-M_002d1_002c-_2026-M_002d_002d_0029"><code>digit-argument (<kbd>M-0</kbd>, <kbd>M-1</kbd>, … <kbd>M--</kbd>)</code></a>:</td><td> </td><td valign="top"><a href="#Numeric-Arguments">Numeric Arguments</a></td></tr> <tr><td></td><td valign="top"><a href="#index-display_002dshell_002dversion-_0028C_002dx-C_002dv_0029"><code>display-shell-version (C-x C-v)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> -<tr><td></td><td valign="top"><a href="#index-do_002duppercase_002dversion-_0028M_002da_002c-M_002db_002c-M_002dx_002c-_2026_0029"><code>do-uppercase-version (M-a, M-b, M-<var>x</var>, …)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-do_002dlowercase_002dversion-_0028M_002dA_002c-M_002dB_002c-M_002dx_002c-_2026_0029"><code>do-lowercase-version (M-A, M-B, M-<var>x</var>, …)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> <tr><td></td><td valign="top"><a href="#index-downcase_002dword-_0028M_002dl_0029"><code>downcase-word (M-l)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr> <tr><td></td><td valign="top"><a href="#index-dump_002dfunctions-_0028_0029"><code>dump-functions ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> <tr><td></td><td valign="top"><a href="#index-dump_002dmacros-_0028_0029"><code>dump-macros ()</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> @@ -14945,7 +15234,7 @@ Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previ <tr><td></td><td valign="top"><a href="#index-dynamic_002dcomplete_002dhistory-_0028M_002dTAB_0029"><code>dynamic-complete-history (M-<span class="key">TAB</span>)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr> <tr><td colspan="4"> <hr></td></tr> <tr><th><a name="Function-Index_fn_letter-E">E</a></th><td></td><td></td></tr> -<tr><td></td><td valign="top"><a href="#index-edit_002dand_002dexecute_002dcommand-_0028C_002dxC_002de_0029"><code>edit-and-execute-command (C-xC-e)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029"><code>edit-and-execute-command (C-x C-e)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> <tr><td></td><td valign="top"><a href="#index-end_002dkbd_002dmacro-_0028C_002dx-_0029_0029"><code>end-kbd-macro (C-x ))</code></a>:</td><td> </td><td valign="top"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr> <tr><td></td><td valign="top"><a href="#index-end_002dof_002dfile-_0028usually-C_002dd_0029"><code><i>end-of-file</i> (usually C-d)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Text">Commands For Text</a></td></tr> <tr><td></td><td valign="top"><a href="#index-end_002dof_002dhistory-_0028M_002d_003e_0029"><code>end-of-history (M->)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> @@ -14968,8 +15257,8 @@ Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previ <tr><td></td><td valign="top"><a href="#index-history_002dexpand_002dline-_0028M_002d_005e_0029"><code>history-expand-line (M-^)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> <tr><td></td><td valign="top"><a href="#index-history_002dsearch_002dbackward-_0028_0029"><code>history-search-backward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> <tr><td></td><td valign="top"><a href="#index-history_002dsearch_002dforward-_0028_0029"><code>history-search-forward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> -<tr><td></td><td valign="top"><a href="#index-history_002dsubstr_002dsearch_002dbackward-_0028_0029"><code>history-substr-search-backward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> -<tr><td></td><td valign="top"><a href="#index-history_002dsubstr_002dsearch_002dforward-_0028_0029"><code>history-substr-search-forward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-history_002dsubstring_002dsearch_002dbackward-_0028_0029"><code>history-substring-search-backward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-history_002dsubstring_002dsearch_002dforward-_0028_0029"><code>history-substring-search-forward ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> <tr><td colspan="4"> <hr></td></tr> <tr><th><a name="Function-Index_fn_letter-I">I</a></th><td></td><td></td></tr> <tr><td></td><td valign="top"><a href="#index-insert_002dcomment-_0028M_002d_0023_0029"><code>insert-comment (M-#)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> @@ -14989,6 +15278,7 @@ Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previ <tr><td colspan="4"> <hr></td></tr> <tr><th><a name="Function-Index_fn_letter-N">N</a></th><td></td><td></td></tr> <tr><td></td><td valign="top"><a href="#index-next_002dhistory-_0028C_002dn_0029"><code>next-history (C-n)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-next_002dscreen_002dline-_0028_0029"><code>next-screen-line ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr> <tr><td></td><td valign="top"><a href="#index-non_002dincremental_002dforward_002dsearch_002dhistory-_0028M_002dn_0029"><code>non-incremental-forward-search-history (M-n)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> <tr><td></td><td valign="top"><a href="#index-non_002dincremental_002dreverse_002dsearch_002dhistory-_0028M_002dp_0029"><code>non-incremental-reverse-search-history (M-p)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> <tr><td colspan="4"> <hr></td></tr> @@ -15005,6 +15295,7 @@ Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previ <tr><td></td><td valign="top"><a href="#index-possible_002dvariable_002dcompletions-_0028C_002dx-_0024_0029"><code>possible-variable-completions (C-x $)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Completion">Commands For Completion</a></td></tr> <tr><td></td><td valign="top"><a href="#index-prefix_002dmeta-_0028ESC_0029"><code>prefix-meta (<span class="key">ESC</span>)</code></a>:</td><td> </td><td valign="top"><a href="#Miscellaneous-Commands">Miscellaneous Commands</a></td></tr> <tr><td></td><td valign="top"><a href="#index-previous_002dhistory-_0028C_002dp_0029"><code>previous-history (C-p)</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-History">Commands For History</a></td></tr> +<tr><td></td><td valign="top"><a href="#index-previous_002dscreen_002dline-_0028_0029"><code>previous-screen-line ()</code></a>:</td><td> </td><td valign="top"><a href="#Commands-For-Moving">Commands For Moving</a></td></tr> <tr><td></td><td valign="top"><a href="#index-print_002dlast_002dkbd_002dmacro-_0028_0029"><code>print-last-kbd-macro ()</code></a>:</td><td> </td><td valign="top"><a href="#Keyboard-Macros">Keyboard Macros</a></td></tr> <tr><td colspan="4"> <hr></td></tr> <tr><th><a name="Function-Index_fn_letter-Q">Q</a></th><td></td><td></td></tr> |