.\" Chet Ramey
.\" Information Network Services
.\" Case Western Reserve University
-.\" chet@ins.CWRU.Edu
+.\" chet@po.cwru.edu
.\"
-.\" Last Change: Tue Mar 14 11:36:43 EST 2000
+.\" Last Change: Thu Sep 28 10:25:59 EDT 2006
.\"
.\" bash_builtins, strip all but Built-Ins section
.if \n(zZ=1 .ig zZ
.if \n(zY=1 .ig zY
-.TH BASH 1 "2000 Mar 14" "GNU Bash-2.04"
+.TH BASH 1 "2006 September 28" "GNU Bash-3.2"
.\"
.\" There's some problem with having a `@'
.\" in a tagged paragraph with the BSD man macros.
[options]
[file]
.SH COPYRIGHT
-.if n Bash is Copyright (C) 1989-1999 by the Free Software Foundation, Inc.
-.if t Bash is Copyright \(co 1989-1999 by the Free Software Foundation, Inc.
+.if n Bash is Copyright (C) 1989-2005 by the Free Software Foundation, Inc.
+.if t Bash is Copyright \(co 1989-2005 by the Free Software Foundation, Inc.
.SH DESCRIPTION
.B Bash
is an \fBsh\fR-compatible command language interpreter that
shells (\fBksh\fP and \fBcsh\fP).
.PP
.B Bash
-is intended to be a conformant implementation of the IEEE
-POSIX Shell and Tools specification (IEEE Working Group 1003\.2).
+is intended to be a conformant implementation of the
+Shell and Utilities portion of the IEEE POSIX specification
+(IEEE Standard 1003.1).
+.B Bash
+can be configured to be POSIX-conformant by default.
.SH OPTIONS
In addition to the single-character shell options documented in the
description of the \fBset\fR builtin command, \fBbash\fR
they are assigned to the positional parameters, starting with
.BR $0 .
.TP
+.B \-i
+If the
+.B \-i
+option is present, the shell is
+.IR interactive .
+.TP
+.B \-l
+Make
+.B bash
+act as if it had been invoked as a login shell (see
+.SM
+.B INVOCATION
+below).
+.TP
.B \-r
If the
.B \-r
.B "RESTRICTED SHELL"
below).
.TP
-.B \-i
-If the
-.B \-i
-option is present, the shell is
-.IR interactive .
-.TP
.B \-s
If the
.B \-s
.TP
.B \-D
A list of all double-quoted strings preceded by \fB$\fP
-is printed on the standard ouput.
+is printed on the standard output.
These are the strings that
are subject to language translation when the current locale
-is not C or POSIX.
+is not \fBC\fP or \fBPOSIX\fP.
This implies the \fB\-n\fP option; no commands will be executed.
.TP
+.B [\-+]O [\fIshopt_option\fP]
+\fIshopt_option\fP is one of the shell options accepted by the
+\fBshopt\fP builtin (see
+.SM
+.B SHELL BUILTIN COMMANDS
+below).
+If \fIshopt_option\fP is present, \fB\-O\fP sets the value of that option;
+\fB+O\fP unsets it.
+If \fIshopt_option\fP is not supplied, the names and values of the shell
+options accepted by \fBshopt\fP are printed on the standard output.
+If the invocation option is \fB+O\fP, the output is displayed in a format
+that may be reused as input.
+.TP
.B \-\-
A
.B \-\-
.B Bash
also interprets a number of multi-character options.
These options must appear on the command line before the
-single-character options in order for them to be recognized.
+single-character options to be recognized.
.PP
.PD 0
.TP
+.B \-\-debugger
+Arrange for the debugger profile to be executed before the shell
+starts.
+Turns on extended debugging mode (see the description of the
+.B extdebug
+option to the
+.B shopt
+builtin below)
+and shell function tracing (see the description of the
+\fB\-o functrace\fP option to the
+.B set
+builtin below).
+.TP
.B \-\-dump\-po\-strings
Equivalent to \fB\-D\fP, but the output is in the GNU \fIgettext\fP
\fBpo\fP (portable object) file format.
.B \-\-help
Display a usage message on standard output and exit successfully.
.TP
-.B \-\-login
-Make
-.B bash
-act as if it had been invoked as a login shell (see
+\fB\-\-init\-file\fP \fIfile\fP
+.PD 0
+.TP
+\fB\-\-rcfile\fP \fIfile\fP
+.PD
+Execute commands from
+.I file
+instead of the standard personal initialization file
+.I ~/.bashrc
+if the shell is interactive (see
.SM
.B INVOCATION
below).
.TP
+.B \-\-login
+Equivalent to \fB\-l\fP.
+.TP
.B \-\-noediting
Do not use the GNU
.B readline
.TP
.B \-\-posix
Change the behavior of \fBbash\fP where the default operation differs
-from the POSIX 1003.2 standard to match the standard.
-.TP
-\fB\-\-rcfile\fP \fIfile\fP
-Execute commands from
-.I file
-instead of the standard personal initialization file
-.I ~/.bashrc
-if the shell is interactive (see
-.SM
-.B INVOCATION
-below).
+from the POSIX standard to match the standard (\fIposix mode\fP).
.TP
.B \-\-restricted
The shell becomes restricted (see
\fBBash\fP's exit status is the exit status 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
+.SM
+.B PATH
+for the script.
.SH INVOCATION
A \fIlogin shell\fP is one whose first character of argument zero is a
.BR \- ,
and without the
.B \-c
option
-whose standard input and output are
+whose standard input and error are
both connected to terminals (as determined by
.IR isatty (3)),
or one started with the
behaves as if the following command were executed:
.sp .5
.RS
-\f(CWif [ \-n "$BASH_ENV" ]; then . "$BASH_ENV"; fi\fP
+.if t \f(CWif [ \-n "$BASH_ENV" ]; then . "$BASH_ENV"; fi\fP
+.if n if [ \-n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
.RE
.sp .5
but the value of the
.PP
If the shell is started with the effective user (group) id not equal to the
real user (group) id, and the \fB\-p\fP option is not supplied, no startup
-files are read, shell functions are not inherited from the environment,
-the \fBSHELLOPTS\fP variable, if it appears in the environment, is ignored,
+files are read, shell functions are not inherited from the environment, the
+.SM
+.B SHELLOPTS
+variable, if it appears in the environment, is ignored,
and the effective user id is set to the real user id.
If the \fB\-p\fP option is supplied at invocation, the startup behavior is
the same, but the effective user id is not reset.
.if n ! case do done elif else esac fi for function if in select then until while { } time [[ ]]
.if t ! case do done elif else esac fi for function if in select then until while { } time [[ ]]
.if t .RE
-.RE
.SH "SHELL GRAMMAR"
.SS Simple Commands
.PP
A \fIsimple command\fP is a sequence of optional variable assignments
followed by \fBblank\fP-separated words and redirections, and
terminated by a \fIcontrol operator\fP. The first word
-specifies the command to be executed. The remaining words are
-passed as arguments to the invoked command.
+specifies the command to be executed, and is passed as argument zero.
+The remaining words are passed as arguments to the invoked command.
.PP
The return value of a \fIsimple command\fP is its exit status, or
128+\fIn\^\fP if the command is terminated by signal
.PP
The standard output of
.I command
-is connected to the standard input of
+is connected via a pipe to the standard input of
.IR command2 .
This connection is performed before any redirections specified by the
command (see
.B REDIRECTION
below).
.PP
+The return status of a pipeline is the exit status of the last
+command, unless the \fBpipefail\fP option is enabled.
+If \fBpipefail\fP 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 successfully.
If the reserved word
.B !
-precedes a pipeline, the exit status of that
-pipeline is the logical NOT of the exit status of the last command.
-Otherwise, the status of the pipeline is the exit status of the last
-command.
+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 before returning a value.
.PP
.BR &,
which have equal precedence.
.PP
+A sequence of one or more newlines may appear in a \fIlist\fP instead
+of a semicolon to delimit commands.
+.PP
If a command is terminated by the control operator
.BR & ,
the shell executes the command in the \fIbackground\fP
A \fIcompound command\fP is one of the following:
.TP
(\fIlist\fP)
-\fIlist\fP is executed in a subshell. Variable assignments and builtin
+\fIlist\fP is executed in a subshell environment (see
+.SM
+\fBCOMMAND EXECUTION ENVIRONMENT\fP
+below).
+Variable assignments and builtin
commands that affect the shell's environment do not remain in effect
after the command completes. The return status is the exit status of
\fIlist\fP.
This is known as a \fIgroup command\fP.
The return status is the exit status of
\fIlist\fP.
+Note that unlike the metacharacters \fB(\fP and \fB)\fP, \fB{\fP and
+\fB}\fP are \fIreserved words\fP 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 \fIlist\fP by whitespace.
.TP
((\fIexpression\fP))
The \fIexpression\fP is evaluated according to the rules described
between the \fB[[\fP and \fB]]\fP; tilde expansion, parameter and
variable expansion, arithmetic expansion, command substitution, process
substitution, and quote removal are performed.
+Conditional operators such as \fB\-f\fP must be unquoted to be recognized
+as primaries.
.if t .sp 0.5
.if n .sp 1
When the \fB==\fP and \fB!=\fP operators are used, the string to the
right of the operator is considered a pattern and matched according
to the rules described below under \fBPattern Matching\fP.
-The return value is 0 if the string matches or does not match
-the pattern, respectively, and 1 otherwise.
+If the shell option
+.B nocasematch
+is enabled, the match is performed without regard to the case
+of alphabetic characters.
+The return value is 0 if the string matches (\fB==\fP) or does not match
+(\fB!=\fP) the pattern, and 1 otherwise.
Any part of the pattern may be quoted to force it to be matched as a
string.
.if t .sp 0.5
.if n .sp 1
+An additional binary operator, \fB=~\fP, is available, with the same
+precedence as \fB==\fP and \fB!=\fP.
+When it is used, the string to the right of the operator is considered
+an extended regular expression and matched accordingly (as in \fIregex\fP(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 shell option
+.B nocasematch
+is enabled, the match is performed without regard to the case
+of alphabetic characters.
+Substrings matched by parenthesized subexpressions within the regular
+expression are saved in the array variable \fBBASH_REMATCH\fP.
+The element of \fBBASH_REMATCH\fP with index 0 is the portion of the string
+matching the entire regular expression.
+The element of \fBBASH_REMATCH\fP with index \fIn\fP is the portion of the
+string matching the \fIn\fPth parenthesized subexpression.
+.if t .sp 0.5
+.if n .sp 1
Expressions may be combined using the following operators, listed
in decreasing order of precedence:
.if t .sp 0.5
.I expression2
is true.
.PD
-.RE
.LP
The \fB&&\fP and
.if t \fB\(bv\(bv\fP
.if n \fB||\fP
-operators do not execute \fIexpression2\fP if the value of
+operators do not evaluate \fIexpression2\fP if the value of
\fIexpression1\fP is sufficient to determine the return value of
the entire conditional expression.
+.RE
.TP
\fBfor\fP \fIname\fP [ \fBin\fP \fIword\fP ] ; \fBdo\fP \fIlist\fP ; \fBdone\fP
The list of words following \fBin\fP is expanded, generating a list
.I list
is executed after each selection until a
.B break
-or
-.B return
command is executed.
The exit status of
.B select
it against each \fIpattern\fP in turn, using the same matching rules
as for pathname expansion (see
.B Pathname Expansion
-below). When a match is found, the
+below).
+The \fIword\fP is expanded using tilde
+expansion, parameter and variable expansion, arithmetic substitution,
+command substitution, process substitution and quote removal.
+Each \fIpattern\fP examined is expanded using tilde
+expansion, parameter and variable expansion, arithmetic substitution,
+command substitution, and process substitution.
+If the shell option
+.B nocasematch
+is enabled, the match is performed without regard to the case
+of alphabetic characters.
+When a match is found, the
corresponding \fIlist\fP is executed. After the first match, no
subsequent matches are attempted. The exit status is zero if no
pattern matches. Otherwise, it is the exit status of the
executed, if present. The exit status is the exit status of the
last command executed, or zero if no condition tested true.
.TP
-.PD 0
\fBwhile\fP \fIlist\fP; \fBdo\fP \fIlist\fP; \fBdone\fP
+.PD 0
.TP
\fBuntil\fP \fIlist\fP; \fBdo\fP \fIlist\fP; \fBdone\fP
.PD
is the exit status
of the last \fBdo\fP \fIlist\fP command executed, or zero if
none was executed.
-.TP
-[ \fBfunction\fP ] \fIname\fP () { \fIlist\fP; }
-This defines a function named \fIname\fP. The \fIbody\fP of the
-function is the
-.I list
-of commands between { and }. This list
-is executed whenever \fIname\fP is specified as the
-name of a simple command. The exit status of a function is
-the exit status of the last command executed in the body. (See
+.SS Shell Function Definitions
+.PP
+A shell function is an object that is called like a simple command and
+executes a compound command with a new set of positional parameters.
+Shell functions are declared as follows:
+.TP
+[ \fBfunction\fP ] \fIname\fP () \fIcompound\-command\fP [\fIredirection\fP]
+This defines a function named \fIname\fP.
+The reserved word \fBfunction\fP is optional.
+If the \fBfunction\fP reserved word is supplied, the parentheses are optional.
+The \fIbody\fP of the function is the compound command
+.I compound\-command
+(see \fBCompound Commands\fP above).
+That command is usually a \fIlist\fP of commands between { and }, but
+may be any command listed under \fBCompound Commands\fP above.
+\fIcompound\-command\fP is executed whenever \fIname\fP is specified as the
+name of a simple command.
+Any redirections (see
+.SM
+.B REDIRECTION
+below) specified when a function is defined are performed
+when the function is executed.
+The exit status of a function definition is zero unless a syntax error
+occurs or a readonly function with the same name already exists.
+When executed, the exit status of a function is the exit status of the
+last command executed in the body. (See
.SM
.B FUNCTIONS
below.)
has special meaning to the shell and must be quoted if it is to
represent itself.
.PP
-When the command history expansion facilities are being used, the
+When the command history expansion facilities are being used
+(see
+.SM
+.B HISTORY EXPANSION
+below), the
\fIhistory expansion\fP character, usually \fB!\fP, must be quoted
to prevent history expansion.
.PP
of all characters within the quotes, with the exception of
.BR $ ,
.BR ` ,
-and
-.BR \e .
+.BR \e ,
+and, when history expansion is enabled,
+.BR ! .
The characters
.B $
and
.BR <newline> .
A double quote may be quoted within double quotes by preceding it with
a backslash.
+If enabled, history expansion will be performed unless an
+.B !
+appearing in double quotes is escaped using a backslash.
+The backslash preceding the
+.B !
+is not removed.
.PP
The special parameters
.B *
.B PARAMETERS
below).
.PP
-Words of the form \fB$\fP'\fIstring\fP' are treated specially. The
+Words of the form \fB$\fP\(aq\fIstring\fP\(aq are treated specially. The
word expands to \fIstring\fP, with backslash-escaped characters replaced
-as specifed by the ANSI C standard. Backslash escape sequences, if
+as specified by the ANSI C standard. Backslash escape sequences, if
present, are decoded as follows:
.RS
.PD 0
.B \e\e
backslash
.TP
-.B \e'
+.B \e\(aq
single quote
.TP
.B \e\fInnn\fP
-the character whose ASCII code is the octal value \fInnn\fP
+the eight-bit character whose value is the octal value \fInnn\fP
(one to three digits)
.TP
-.B \ex\fInnn\fP
-the character whose ASCII code is the hexadecimal value \fInnn\fP
-(one to three digits)
+.B \ex\fIHH\fP
+the eight-bit character whose value is the hexadecimal value \fIHH\fP
+(one or two hex digits)
+.TP
+.B \ec\fIx\fP
+a control-\fIx\fP character
.PD
.RE
.LP
.IR name ,
a number, or one of the special characters listed below under
.BR "Special Parameters" .
-For the shell's purposes, a
+A
.I variable
is a parameter denoted by a
.IR name .
+A variable has a \fIvalue\fP and zero or more \fIattributes\fP.
+Attributes are assigned using the
+.B declare
+builtin command (see
+.B declare
+below in
+.SM
+.BR "SHELL BUILTIN COMMANDS" ).
.PP
A parameter is set if it has been assigned a value. The null string is
a valid value. Once a variable is set, it may be unset only by using
.B EXPANSION
below). If the variable has its
.B integer
-attribute set (see
-.B declare
-below in
-.SM
-.BR "SHELL BUILTIN COMMANDS" )
-then
+attribute set, then
.I value
-is subject to arithmetic expansion even if the $((...)) expansion is
+is evaluated as an arithmetic expression even if the $((...)) expansion is
not used (see
.B "Arithmetic Expansion"
below).
of \fB"$@"\fP as explained below under
.BR "Special Parameters" .
Pathname expansion is not performed.
+Assignment statements may also appear as arguments to the
+.BR alias ,
+.BR declare ,
+.BR typeset ,
+.BR export ,
+.BR readonly ,
+and
+.B local
+builtin commands.
+.PP
+In the context where an assignment statement is assigning a value
+to a shell variable or array index, the += operator can be used to
+append to or add to the variable's previous value.
+When += is applied to a variable for which the integer attribute has been
+set, \fIvalue\fP is evaluated as an arithmetic expression and added to the
+variable's current value, which is also evaluated.
+When += is applied to an array variable using compound assignment (see
+.B Arrays
+below), the
+variable's value is not unset (as it is when using =), and new values are
+appended to the array beginning at one greater than the array's maximum index.
+When applied to a string-valued variable, \fIvalue\fP is expanded and
+appended to the variable's value.
.SS Positional Parameters
.PP
A
expansion occurs within double quotes, each parameter expands to a
separate word. That is, "\fB$@\fP" is equivalent to
"\fB$1\fP" "\fB$2\fP" ...
+If the double-quoted expansion occurs within a word, the expansion of
+the first parameter is joined with the beginning part of the original
+word, and the expansion of the last parameter is joined with the last
+part of the original word.
When there are no positional parameters, "\fB$@\fP" and
.B $@
expand to nothing (i.e., they are removed).
as given by argument zero.
.TP
.B _
-At shell startup, set to the absolute file name of the shell or shell
-script being executed as passed in the argument list.
+At shell startup, set to the absolute pathname used to invoke the
+shell or shell script being executed as passed in the environment
+or argument list.
Subsequently, expands to the last argument to the previous command,
after expansion.
-Also set to the full file name of each command executed and placed in
-the environment exported to that command.
+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.
.PD
.PP
.PD 0
.TP
-.B PPID
-The process ID of the shell's parent. This variable is readonly.
-.TP
-.B PWD
-The current working directory as set by the
-.B cd
-command.
-.TP
-.B OLDPWD
-The previous working directory as set by the
-.B cd
-command.
-.TP
-.B REPLY
-Set to the line of input read by the
-.B read
-builtin command when no arguments are supplied.
-.TP
-.B UID
-Expands to the user ID of the current user, initialized at shell startup.
-This variable is readonly.
-.TP
-.B EUID
-Expands to the effective user ID of the current user, initialized at
-shell startup. This variable is readonly.
-.TP
-.B GROUPS
-An array variable containing the list of groups of which the current
-user is a member.
-Assignments to
-.SM
-.B GROUPS
-have no effect and are silently discarded.
-If
-.SM
-.B GROUPS
-is unset, it loses its special properties, even if it is
-subsequently reset.
-.TP
.B BASH
Expands to the full file name used to invoke this instance of
.BR bash .
.TP
-.B BASH_VERSION
-Expands to a string describing the version of this instance of
-.BR bash .
+.B BASH_ARGC
+An array variable whose values are the number of parameters in each
+frame of the current bash execution call stack.
+The number of
+parameters to the current subroutine (shell function or script executed
+with \fB.\fP or \fBsource\fP) is at the top of the stack.
+When a subroutine is executed, the number of parameters passed is pushed onto
+\fBBASH_ARGC\fP.
+The shell sets \fBBASH_ARGC\fP only when in extended debugging mode
+(see the description of the
+.B extdebug
+option to the
+.B shopt
+builtin below)
+.TP
+.B BASH_ARGV
+An array variable containing all of the parameters in the current bash
+execution call stack. The final parameter of the last subroutine call
+is at the top of the stack; the first parameter of the initial call is
+at the bottom. When a subroutine is executed, the parameters supplied
+are pushed onto \fBBASH_ARGV\fP.
+The shell sets \fBBASH_ARGV\fP only when in extended debugging mode
+(see the description of the
+.B extdebug
+option to the
+.B shopt
+builtin below)
+.TP
+.B BASH_COMMAND
+The command currently being executed or about to be executed, unless the
+shell is executing a command as the result of a trap,
+in which case it is the command executing at the time of the trap.
+.TP
+.B BASH_EXECUTION_STRING
+The command argument to the \fB\-c\fP invocation option.
+.TP
+.B BASH_LINENO
+An array variable whose members are the line numbers in source files
+corresponding to each member of \fBFUNCNAME\fP.
+\fB${BASH_LINENO[\fP\fI$i\fP\fB]}\fP is the line number in the source
+file where \fB${FUNCNAME[\fP\fI$ifP\fB]}\fP was called.
+The corresponding source file name is \fB${BASH_SOURCE[\fP\fI$i\fP\fB]}\fB.
+Use \fBLINENO\fP to obtain the current line number.
+.TP
+.B BASH_REMATCH
+An array variable whose members are assigned by the \fB=~\fP binary
+operator to the \fB[[\fP conditional command.
+The element with index 0 is the portion of the string
+matching the entire regular expression.
+The element with index \fIn\fP is the portion of the
+string matching the \fIn\fPth parenthesized subexpression.
+This variable is read-only.
+.TP
+.B BASH_SOURCE
+An array variable whose members are the source filenames corresponding
+to the elements in the \fBFUNCNAME\fP array variable.
+.TP
+.B BASH_SUBSHELL
+Incremented by one each time a subshell or subshell environment is spawned.
+The initial value is 0.
.TP
.B BASH_VERSINFO
A readonly array variable whose members hold version information for
.PD
.RE
.TP
-.B SHLVL
-Incremented by one each time an instance of
-.B bash
-is started.
+.B BASH_VERSION
+Expands to a string describing the version of this instance of
+.BR bash .
.TP
-.B RANDOM
-Each time this parameter is referenced, a random integer between
-0 and 32767 is
-generated. The sequence of random numbers may be initialized by assigning
-a value to
-.SM
-.BR RANDOM .
-If
-.SM
-.B RANDOM
-is unset, it loses its special properties, even if it is
-subsequently reset.
+.B COMP_CWORD
+An index into \fB${COMP_WORDS}\fP of the word containing the current
+cursor position.
+This variable is available only in shell functions invoked by the
+programmable completion facilities (see \fBProgrammable Completion\fP
+below).
.TP
-.B SECONDS
-Each time this parameter is
-referenced, the number of seconds since shell invocation is returned. If a
-value is assigned to
-.SM
-.BR SECONDS ,
-the value returned upon subsequent
-references is
-the number of seconds since the assignment plus the value assigned.
-If
-.SM
-.B SECONDS
-is unset, it loses its special properties, even if it is
-subsequently reset.
+.B COMP_LINE
+The current command line.
+This variable is available only in shell functions and external
+commands invoked by the
+programmable completion facilities (see \fBProgrammable Completion\fP
+below).
.TP
-.B LINENO
-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
-.SM
-.B LINENO
-is unset, it loses its special properties, even if it is
-subsequently reset.
+.B COMP_POINT
+The index of the current cursor position relative to the beginning of
+the current command.
+If the current cursor position is at the end of the current command,
+the value of this variable is equal to \fB${#COMP_LINE}\fP.
+This variable is available only in shell functions and external
+commands invoked by the
+programmable completion facilities (see \fBProgrammable Completion\fP
+below).
.TP
-.B HISTCMD
-The history number, or index in the history list, of the current
-command.
+.B COMP_WORDBREAKS
+The set of characters that the Readline library treats as word
+separators when performing word completion.
If
.SM
-.B HISTCMD
+.B COMP_WORDBREAKS
is unset, it loses its special properties, even if it is
subsequently reset.
.TP
-.B FUNCNAME
-The name of any currently-executing shell function.
-This variable exists only when a shell function is executing.
-Assignments to
-.SM
-.B FUNCNAME
-have no effect and are silently discarded.
-If
-.SM
-.B FUNCNAME
-is unset, it loses its special properties, even if it is
-subsequently reset.
+.B COMP_WORDS
+An array variable (see \fBArrays\fP below) consisting of the individual
+words in the current command line.
+The words are split on shell metacharacters as the shell parser would
+separate them.
+This variable is available only in shell functions invoked by the
+programmable completion facilities (see \fBProgrammable Completion\fP
+below).
.TP
.B DIRSTACK
An array variable (see
is unset, it loses its special properties, even if it is
subsequently reset.
.TP
-.B PIPESTATUS
-An array variable (see
-.B Arrays
-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).
+.B EUID
+Expands to the effective user ID of the current user, initialized at
+shell startup. This variable is readonly.
.TP
-.B OPTARG
-The value of the last option argument processed by the
-.B getopts
-builtin command (see
+.B FUNCNAME
+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 bottom-most element is "main".
+This variable exists only when a shell function is executing.
+Assignments to
.SM
-.B SHELL BUILTIN COMMANDS
-below).
+.B FUNCNAME
+have no effect and return an error status.
+If
+.SM
+.B FUNCNAME
+is unset, it loses its special properties, even if it is
+subsequently reset.
.TP
-.B OPTIND
-The index of the next argument to be processed by the
-.B getopts
-builtin command (see
+.B GROUPS
+An array variable containing the list of groups of which the current
+user is a member.
+Assignments to
.SM
-.B SHELL BUILTIN COMMANDS
-below).
+.B GROUPS
+have no effect and return an error status.
+If
+.SM
+.B GROUPS
+is unset, it loses its special properties, even if it is
+subsequently reset.
+.TP
+.B HISTCMD
+The history number, or index in the history list, of the current
+command.
+If
+.SM
+.B HISTCMD
+is unset, it loses its special properties, even if it is
+subsequently reset.
.TP
.B HOSTNAME
Automatically set to the name of the current host.
is executing.
The default is system-dependent.
.TP
-.B OSTYPE
-Automatically set to a string that
-describes the operating system on which
-.B bash
-is executing.
-The default is system-dependent.
+.B LINENO
+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
+.SM
+.B LINENO
+is unset, it loses its special properties, even if it is
+subsequently reset.
.TP
.B MACHTYPE
Automatically set to a string that fully describes the system
is executing, in the standard GNU \fIcpu-company-system\fP format.
The default is system-dependent.
.TP
+.B OLDPWD
+The previous working directory as set by the
+.B cd
+command.
+.TP
+.B OPTARG
+The value of the last option argument processed by the
+.B getopts
+builtin command (see
+.SM
+.B SHELL BUILTIN COMMANDS
+below).
+.TP
+.B OPTIND
+The index of the next argument to be processed by the
+.B getopts
+builtin command (see
+.SM
+.B SHELL BUILTIN COMMANDS
+below).
+.TP
+.B OSTYPE
+Automatically set to a string that
+describes the operating system on which
+.B bash
+is executing.
+The default is system-dependent.
+.TP
+.B PIPESTATUS
+An array variable (see
+.B Arrays
+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).
+.TP
+.B PPID
+The process ID of the shell's parent. This variable is readonly.
+.TP
+.B PWD
+The current working directory as set by the
+.B cd
+command.
+.TP
+.B RANDOM
+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
+.SM
+.BR RANDOM .
+If
+.SM
+.B RANDOM
+is unset, it loses its special properties, even if it is
+subsequently reset.
+.TP
+.B REPLY
+Set to the line of input read by the
+.B read
+builtin command when no arguments are supplied.
+.TP
+.B SECONDS
+Each time this parameter is
+referenced, the number of seconds since shell invocation is returned. If a
+value is assigned to
+.SM
+.BR SECONDS ,
+the value returned upon subsequent
+references is
+the number of seconds since the assignment plus the value assigned.
+If
+.SM
+.B SECONDS
+is unset, it loses its special properties, even if it is
+subsequently reset.
+.TP
.B SHELLOPTS
A colon-separated list of enabled shell options. Each word in
the list is a valid argument for the
reading any startup files.
This variable is read-only.
.TP
-.B COMP_WORDS
-An array variable (see \fBArrays\fP below) consisting of the individual
-words in the current command line.
-This variable is available only in shell functions invoked by the
-programmable completion facilities (see \fBProgrammable Completion\fP
-below).
-.TP
-.B COMP_CWORD
-An index into \fB${COMP_WORDS}\fP of the word containing the current
-cursor position.
-This variable is available only in shell functions invoked by the
-programmable completion facilities (see \fBProgrammable Completion\fP
-below).
-.TP
-.B COMP_LINE
-The current command line.
-This variable is available only in shell functions and external
-commands invoked by the
-programmable completion facilities (see \fBProgrammable Completion\fP
-below).
+.B SHLVL
+Incremented by one each time an instance of
+.B bash
+is started.
.TP
-.B COMP_POINT
-The index of the current cursor position relative to the beginning of
-the current command.
-If the current cursor position is at the end of the current command,
-the value of this variable is equal to \fB${#COMP_LINE}\fP.
-This variable is available only in shell functions and external
-commands invoked by the
-programmable completion facilities (see \fBProgrammable Completion\fP
-below).
+.B UID
+Expands to the user ID of the current user, initialized at shell startup.
+This variable is readonly.
.PD
.PP
The following variables are used by the shell. In some cases,
.PP
.PD 0
.TP
+.B BASH_ENV
+If this parameter is set when \fBbash\fP is executing a shell script,
+its value is interpreted as a filename containing commands to
+initialize the shell, as in
+.IR ~/.bashrc .
+The value of
+.SM
+.B BASH_ENV
+is subjected to parameter expansion, command substitution, and arithmetic
+expansion before being interpreted as a file name.
+.SM
+.B PATH
+is not used to search for the resultant file name.
+.TP
+.B CDPATH
+The search path for the
+.B cd
+command.
+This is a colon-separated list of directories in which the shell looks
+for destination directories specified by the
+.B cd
+command.
+A sample value is
+.if t \f(CW".:~:/usr"\fP.
+.if n ".:~:/usr".
+.TP
+.B COLUMNS
+Used by the \fBselect\fP builtin command to determine the terminal width
+when printing selection lists. Automatically set upon receipt of a SIGWINCH.
+.TP
+.B COMPREPLY
+An array variable from which \fBbash\fP reads the possible completions
+generated by a shell function invoked by the programmable completion
+facility (see \fBProgrammable Completion\fP below).
+.TP
+.B EMACS
+If \fBbash\fP finds this variable in the environment when the shell starts
+with value
+.if t \f(CWt\fP,
+.if n "t",
+it assumes that the shell is running in an emacs shell buffer and disables
+line editing.
+.TP
+.B FCEDIT
+The default editor for the
+.B fc
+builtin command.
+.TP
+.B FIGNORE
+A colon-separated list of suffixes to ignore when performing
+filename completion (see
+.SM
+.B READLINE
+below).
+A filename whose suffix matches one of the entries in
+.SM
+.B FIGNORE
+is excluded from the list of matched filenames.
+A sample value is
+.if t \f(CW".o:~"\fP.
+.if n ".o:~".
+.TP
+.B GLOBIGNORE
+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
+.SM
+.BR GLOBIGNORE ,
+it is removed from the list of matches.
+.TP
+.B HISTCONTROL
+A colon-separated list of values controlling how commands are saved on
+the history list.
+If the list of values includes
+.IR ignorespace ,
+lines which begin with a
+.B space
+character are not saved in the history list.
+A value of
+.I ignoredups
+causes lines matching the previous history entry to not be saved.
+A value of
+.I ignoreboth
+is shorthand for \fIignorespace\fP and \fIignoredups\fP.
+A value of
+.IR erasedups
+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 \fBHISTCONTROL\fP 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
+.BR HISTIGNORE .
+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
+.BR HISTCONTROL .
+.TP
+.B HISTFILE
+The name of the file in which command history is saved (see
+.SM
+.B HISTORY
+below). The default value is \fI~/.bash_history\fP. If unset, the
+command history is not saved when an interactive shell exits.
+.TP
+.B HISTFILESIZE
+The maximum number of lines contained in the history file. When this
+variable is assigned a value, the history file is truncated, if
+necessary, by removing the oldest entries,
+to contain no more than that number of lines. The default
+value is 500. The history file is also truncated to this size after
+writing it when an interactive shell exits.
+.TP
+.B HISTIGNORE
+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 complete line (no implicit
+`\fB*\fP' is appended). Each pattern is tested against the line
+after the checks specified by
+.B HISTCONTROL
+are applied.
+In addition to the normal shell pattern matching characters, `\fB&\fP'
+matches the previous history line. `\fB&\fP' 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
+.BR HISTIGNORE .
+.TP
+.B HISTSIZE
+The number of commands to remember in the command history (see
+.SM
+.B HISTORY
+below). The default value is 500.
+.TP
+.B HISTTIMEFORMAT
+If this variable is set and not null, its value is used as a format string
+for \fIstrftime\fP(3) to print the time stamp associated with each history
+entry displayed by the \fBhistory\fP builtin.
+If this variable is set, time stamps are written to the history file so
+they may be preserved across shell sessions.
+.TP
+.B HOME
+The home directory of the current user; the default argument for the
+\fBcd\fP builtin command.
+The value of this variable is also used when performing tilde expansion.
+.TP
+.B HOSTFILE
+Contains the name of a file in the same format as
+.FN /etc/hosts
+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,
+.B bash
+adds the contents of the new file to the existing list.
+If
+.SM
+.B HOSTFILE
+is set, but has no value, \fBbash\fP attempts to read
+.FN /etc/hosts
+to obtain the list of possible hostname completions.
+When
+.SM
+.B HOSTFILE
+is unset, the hostname list is cleared.
+.TP
.B IFS
The
.I Internal Field Separator
builtin command. The default value is
``<space><tab><newline>''.
.TP
-.B PATH
-The search path for commands. It
-is a colon-separated list of directories in which
-the shell looks for commands (see
+.B IGNOREEOF
+Controls the
+action of an interactive shell on receipt of an
.SM
-.B COMMAND EXECUTION
-below). The default path is system-dependent,
-and is set by the administrator who installs
-.BR bash .
-A common value is ``/usr/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin:.''.
+.B EOF
+character as the sole input. If set, the value is the number of
+consecutive
+.SM
+.B EOF
+characters which must be
+typed as the first characters on an input line before
+.B bash
+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,
+.SM
+.B EOF
+signifies the end of input to the shell.
+.TP
+.B INPUTRC
+The filename for the
+.B readline
+startup file, overriding the default of
+.FN ~/.inputrc
+(see
+.SM
+.B READLINE
+below).
+.TP
+.B LANG
+Used to determine the locale category for any category not specifically
+selected with a variable starting with \fBLC_\fP.
+.TP
+.B LC_ALL
+This variable overrides the value of \fBLANG\fP and any other
+\fBLC_\fP variable specifying a locale category.
+.TP
+.B LC_COLLATE
+This variable determines the collation order used when sorting the
+results of pathname expansion, and determines the behavior of range
+expressions, equivalence classes, and collating sequences within
+pathname expansion and pattern matching.
.TP
-.B HOME
-The home directory of the current user; the default argument for the
-\fBcd\fP builtin command.
-The value of this variable is also used when performing tilde expansion.
+.B LC_CTYPE
+This variable determines the interpretation of characters and the
+behavior of character classes within pathname expansion and pattern
+matching.
.TP
-.B CDPATH
-The search path for the
-.B cd
-command.
-This is a colon-separated list of directories in which the shell looks
-for destination directories specified by the
-.B cd
-command.
-A sample value is ``.:~:/usr''.
+.B LC_MESSAGES
+This variable determines the locale used to translate double-quoted
+strings preceded by a \fB$\fP.
.TP
-.B BASH_ENV
-If this parameter is set when \fBbash\fP is executing a shell script,
-its value is interpreted as a filename containing commands to
-initialize the shell, as in
-.IR ~/.bashrc .
-The value of
-.SM
-.B BASH_ENV
-is subjected to parameter expansion, command substitution, and arithmetic
-expansion before being interpreted as a file name.
-.SM
-.B PATH
-is not used to search for the resultant file name.
+.B LC_NUMERIC
+This variable determines the locale category used for number formatting.
+.TP
+.B LINES
+Used by the \fBselect\fP builtin command to determine the column length
+for printing selection lists. Automatically set upon receipt of a SIGWINCH.
.TP
.B MAIL
If this parameter is set to a file name and the
.B bash
checks for mail. The default is 60 seconds. When it is time to check
for mail, the shell does so before displaying the primary prompt.
-If this variable is unset, the shell disables mail checking.
+If this variable is unset, or set to a value that is not a number
+greater than or equal to zero, the shell disables mail checking.
.TP
.B MAILPATH
A colon-separated list of file names to be checked for mail.
Example:
.RS
.PP
-\fBMAILPATH\fP='/var/mail/bfox?"You have mail":~/shell\-mail?"$_ has mail!"'
+\fBMAILPATH\fP=\(aq/var/mail/bfox?"You have mail":~/shell\-mail?"$_ has mail!"\(aq
.PP
.B Bash
supplies a default value for this variable, but the location of the user
mail files that it uses is system dependent (e.g., /var/mail/\fB$USER\fP).
.RE
.TP
+.B OPTERR
+If set to the value 1,
+.B bash
+displays error messages generated by the
+.B getopts
+builtin command (see
+.SM
+.B SHELL BUILTIN COMMANDS
+below).
+.SM
+.B OPTERR
+is initialized to 1 each time the shell is invoked or a shell
+script is executed.
+.TP
+.B PATH
+The search path for commands. It
+is a colon-separated list of directories in which
+the shell looks for commands (see
+.SM
+.B COMMAND EXECUTION
+below).
+A zero-length (null) directory name in the value of \fBPATH\fP indicates the
+current directory.
+A null directory name may appear as two adjacent colons, or as an initial
+or trailing colon.
+The default path is system-dependent,
+and is set by the administrator who installs
+.BR bash .
+A common value is
+.if t \f(CW/usr/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin\fP.
+.if n ``/usr/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin''.
+.TP
+.B POSIXLY_CORRECT
+If this variable is in the environment when \fBbash\fP starts, the shell
+enters \fIposix mode\fP before reading the startup files, as if the
+.B \-\-posix
+invocation option had been supplied. If it is set while the shell is
+running, \fBbash\fP enables \fIposix mode\fP, as if the command
+.if t \f(CWset -o posix\fP
+.if n \fIset -o posix\fP
+had been executed.
+.TP
+.B PROMPT_COMMAND
+If set, the value is executed as a command prior to issuing each primary
+prompt.
+.TP
.B PS1
The value of this parameter is expanded (see
.SM
is replicated multiple times, as necessary, to indicate multiple
levels of indirection. The default is ``\fB+ \fP''.
.TP
+.B SHELL
+The full pathname to the shell is kept in this environment variable.
+If it is not set when the shell starts,
+.B bash
+assigns to it the full pathname of the current user's login shell.
+.TP
.B TIMEFORMAT
The value of this parameter is used as a format string specifying
how the timing information for pipelines prefixed with the
included.
.IP
If this variable is not set, \fBbash\fP acts as if it had the
-value \fB$'\enreal\et%3lR\enuser\et%3lU\ensys\t%3lS'\fP.
+value \fB$\(aq\enreal\et%3lR\enuser\et%3lU\ensys\t%3lS\(aq\fP.
If the value is null, no timing information is displayed.
A trailing newline is added when the format string is displayed.
.TP
-.B HISTSIZE
-The number of commands to remember in the command history (see
-.SM
-.B HISTORY
-below). The default value is 500.
-.TP
-.B HISTFILE
-The name of the file in which command history is saved (see
-.SM
-.B HISTORY
-below). The default value is \fI~/.bash_history\fP. If unset, the
-command history is not saved when an interactive shell exits.
-.TP
-.B HISTFILESIZE
-The maximum number of lines contained in the history file. When this
-variable is assigned a value, the history file is truncated, if
-necessary, to contain no more than that number of lines. The default
-value is 500. The history file is also truncated to this size after
-writing it when an interactive shell exits.
-.TP
-.B OPTERR
-If set to the value 1,
-.B bash
-displays error messages generated by the
-.B getopts
-builtin command (see
-.SM
-.B SHELL BUILTIN COMMANDS
-below).
-.SM
-.B OPTERR
-is initialized to 1 each time the shell is invoked or a shell
-script is executed.
-.TP
-.B LANG
-Used to determine the locale category for any category not specifically
-selected with a variable starting with \fBLC_\fP.
-.TP
-.B LC_ALL
-This variable overrides the value of \fBLANG\fP and any other
-\fBLC_\fP variable specifying a locale category.
-.TP
-.B LC_COLLATE
-This variable determines the collation order used when sorting the
-results of pathname expansion, and determines the behavior of range
-expressions, equivalence classes, and collating sequences within
-pathname expansion and pattern matching.
-.TP
-.B LC_CTYPE
-This variable determines the interpretation of characters and the
-behavior of character classes within pathname expansion and pattern
-matching.
-.TP
-.B LC_MESSAGES
-This variable determines the locale used to translate double-quoted
-strings preceded by a \fB$\fP.
-.TP
-.B LC_NUMERIC
-This variable determines the locale category used for number formatting.
-.TP
-.B PROMPT_COMMAND
-If set, the value is executed as a command prior to issuing each primary
-prompt.
-.TP
-.B IGNOREEOF
-Controls the
-action of an interactive shell on receipt of an
-.SM
-.B EOF
-character as the sole input. If set, the value is the number of
-consecutive
-.SM
-.B EOF
-characters which must be
-typed as the first characters on an input line before
-.B bash
-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,
-.SM
-.B EOF
-signifies the end of input to the shell.
-.TP
.B TMOUT
-If set to a value greater than zero, the value is interpreted as the
+If set to a value greater than zero, \fBTMOUT\fP is treated as the
+default timeout for the \fBread\fP builtin.
+The \fBselect\fP command terminates if input does not arrive
+after \fBTMOUT\fP seconds when input is coming from a terminal.
+In an interactive shell, the value is interpreted as the
number of seconds to wait for input after issuing the primary prompt.
.B Bash
terminates after waiting for that number of seconds if input does
-not arrive.
-.TP
-.B FCEDIT
-The default editor for the
-.B fc
-builtin command.
-.TP
-.B FIGNORE
-A colon-separated list of suffixes to ignore when performing
-filename completion (see
-.SM
-.B READLINE
-below).
-A filename whose suffix matches one of the entries in
-.SM
-.B FIGNORE
-is excluded from the list of matched filenames.
-A sample value is ``.o:~''.
-.TP
-.B GLOBIGNORE
-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
-.SM
-.BR GLOBIGNORE ,
-it is removed from the list of matches.
-.TP
-.B INPUTRC
-The filename for the
-.B readline
-startup file, overriding the default of
-.FN ~/.inputrc
-(see
-.SM
-.B READLINE
-below).
-.TP
-.B HISTCONTROL
-If set to a value of
-.IR ignorespace ,
-lines which begin with a
-.B space
-character are not entered on the history list.
-If set to a value of
-.IR ignoredups ,
-lines matching the last history line are not entered.
-A value of
-.I ignoreboth
-combines the two options.
-If unset, or if set to any other value than those above,
-all lines read
-by the parser are saved on the history list, subject to the value
-of
-.BR HISTIGNORE .
-This variable's function is superseded by
-.BR HISTIGNORE .
-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
-.BR HISTCONTROL .
-.TP
-.B HISTIGNORE
-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 complete line (no implicit
-`\fB*\fP' is appended). Each pattern is tested against the line
-after the checks specified by
-.B HISTCONTROL
-are applied.
-In addition to the normal shell pattern matching characters, `\fB&\fP'
-matches the previous history line. `\fB&\fP' 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
-.BR HISTIGNORE .
-.TP
-.B histchars
-The two or three characters which control history expansion
-and tokenization (see
-.SM
-.B HISTORY EXPANSION
-below). The first character is the \fIhistory expansion\fP character,
-the character which signals the start of a history
-expansion, normally `\fB!\fP'.
-The second character is the \fIquick substitution\fP
-character, which is used as shorthand for re-running the previous
-command entered, substituting one string for another in the command.
-The default is `\fB^\fP'.
-The optional third character is the character
-which indicates that the remainder of the line is a comment when found
-as the first character of a word, normally `\fB#\fP'. The history
-comment character causes history substitution to be skipped for the
-remaining words on the line. It does not necessarily cause the shell
-parser to treat the rest of the line as a comment.
-.TP
-.B HOSTFILE
-Contains the name of a file in the same format as
-.FN /etc/hosts
-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,
-.B bash
-adds the contents of the new file to the existing list.
-If
-.SM
-.B HOSTFILE
-is set, but has no value, \fBbash\fP attempts to read
-.FN /etc/hosts
-to obtain the list of possible hostname completions.
-When
-.SM
-.B HOSTFILE
-is unset, the hostname list is cleared.
+not arrive.
+.TP
+.B TMPDIR
+If set, \fBBash\fP uses its value as the name of a directory in which
+\fBBash\fP creates temporary files for the shell's use.
.TP
.B auto_resume
This variable controls how the shell interacts with the user and
.B JOB CONTROL
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
-.B %
-job identifier.
+analogous to the \fB%\fP\fIstring\fP job identifier.
.TP
-.B COMPREPLY
-An array variable from which \fBbash\fP reads the possible completions
-generated by a shell function invoked by the programmable completion
-facility (see \fBProgrammable Completion\fP below).
+.B histchars
+The two or three characters which control history expansion
+and tokenization (see
+.SM
+.B HISTORY EXPANSION
+below). The first character is the \fIhistory expansion\fP character,
+the character which signals the start of a history
+expansion, normally `\fB!\fP'.
+The second character is the \fIquick substitution\fP
+character, which is used as shorthand for re-running the previous
+command entered, substituting one string for another in the command.
+The default is `\fB^\fP'.
+The optional third character is the character
+which indicates that the remainder of the line is a comment when found
+as the first character of a word, normally `\fB#\fP'. The history
+comment character causes history substitution to be skipped for the
+remaining words on the line. It does not necessarily cause the shell
+parser to treat the rest of the line as a comment.
.PD
.SS Arrays
.B Bash
.B IFS
special variable, and ${\fIname\fP[@]} expands each element of
\fIname\fP to a separate word. When there are no array members,
-${\fIname\fP[@]} expands to nothing. This is analogous to the expansion
+${\fIname\fP[@]} 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 \fB*\fP and \fB@\fP (see
.B Special Parameters
above). ${#\fIname\fP[\fIsubscript\fP]} expands to the length of
.B unset
builtin is used to destroy arrays. \fBunset\fP \fIname\fP[\fIsubscript\fP]
destroys the array element at index \fIsubscript\fP.
+Care must be taken to avoid unwanted side effects caused by filename
+generation.
\fBunset\fP \fIname\fP, where \fIname\fP is an array, or
\fBunset\fP \fIname\fP[\fIsubscript\fP], where
\fIsubscript\fP is \fB*\fP or \fB@\fP, removes the entire array.
need not exist. Patterns to be brace expanded take
the form of an optional
.IR preamble ,
-followed by a series of comma-separated strings
-between a pair of braces, followed by an optional
+followed by either a series of comma-separated strings or
+a sequence expression between a pair of braces, followed by
+an optional
.IR postscript .
The preamble is prefixed to each string contained
within the braces, and the postscript is then appended
string are not sorted; left to right order is preserved.
For example, a\fB{\fPd,c,b\fB}\fPe expands into `ade ace abe'.
.PP
+A sequence expression takes the form \fB{\fP\fIx\fP\fB..\fP\fIy\fP\fB}\fP,
+where \fIx\fP and \fIy\fP are either integers or single characters.
+When integers are supplied, the expression expands to each number between
+\fIx\fP and \fIy\fP, inclusive.
+When characters are supplied, the expression expands to each character
+lexicographically between \fIx\fP and \fIy\fP, inclusive. Note that
+both \fIx\fP and \fIy\fP must be of the same type.
+.PP
Brace expansion is performed before any other expansions,
and any characters special to other expansions are preserved
in the result. It is strictly textual.
expansion or the text between the braces.
.PP
A correctly-formed brace expansion must contain unquoted opening
-and closing braces, and at least one unquoted comma.
+and closing braces, and at least one unquoted comma or a valid
+sequence expression.
Any incorrectly formed brace expansion is left unchanged.
A \fB{\fP or \fB,\fP may be quoted with a backslash to prevent its
being considered part of a brace expression.
Each variable assignment is checked for unquoted tilde-prefixes immediately
following a
.B :
-or
+or the first
.BR = .
In these cases, tilde expansion is also performed.
Consequently, one may use file names with tildes in assignments to
.PP
When braces are used, the matching ending brace is the first `\fB}\fP'
not escaped by a backslash or within a quoted string, and not within an
-embedded arithmetic expansion, command substitution, or paramter
+embedded arithmetic expansion, command substitution, or parameter
expansion.
.PP
.PD 0
expanded and that value is used in the rest of the substitution, rather
than the value of \fIparameter\fP itself.
This is known as \fIindirect expansion\fP.
-The exception to this is the expansion of ${!\fIprefix\fP*}
-described below.
+The exceptions to this are the expansions of ${!\fIprefix\fP*} and
+${\fB!\fP\fIname\fP[\fI@\fP]} described below.
+The exclamation point must immediately follow the left brace in order to
+introduce indirection.
.PP
In each of the cases below, \fIword\fP is subject to tilde expansion,
parameter expansion, command substitution, and arithmetic expansion.
.I word
is substituted.
.TP
-.PD 0
${\fIparameter\fP\fB:\fP\fIoffset\fP}
+.PD 0
.TP
${\fIparameter\fP\fB:\fP\fIoffset\fP\fB:\fP\fIlength\fP}
.PD
If \fIparameter\fP is an array name indexed by @ or *,
the result is the \fIlength\fP
members of the array beginning with ${\fIparameter\fP[\fIoffset\fP]}.
+A negative \fIoffset\fP is taken relative to one greater than the maximum
+index of the specified array.
+Note that a negative offset must be separated from the colon by at least
+one space to avoid being confused with the :- expansion.
Substring indexing is zero-based unless the positional parameters
are used, in which case the indexing starts at 1.
.TP
${\fB!\fP\fIprefix\fP\fB*\fP}
+.PD 0
+.TP
+${\fB!\fP\fIprefix\fP\fB@\fP}
+.PD
Expands to the names of variables whose names begin with \fIprefix\fP,
separated by the first character of the
.SM
.B IFS
special variable.
.TP
+${\fB!\fP\fIname\fP[\fI@\fP]}
+.PD 0
+.TP
+${\fB!\fP\fIname\fP[\fI*\fP]}
+.PD
+If \fIname\fP is an array variable, expands to the list of array indices
+(keys) assigned in \fIname\fP.
+If \fIname\fP is not an array, expands to 0 if \fIname\fP is set and null
+otherwise.
+When \fI@\fP is used and the expansion appears within double quotes, each
+key expands to a separate word.
+.TP
${\fB#\fP\fIparameter\fP}
The length in characters of the value of \fIparameter\fP is substituted.
If
.BR @ ,
the value substituted is the number of elements in the array.
.TP
-.PD 0
${\fIparameter\fP\fB#\fP\fIword\fP}
+.PD 0
.TP
${\fIparameter\fP\fB##\fP\fIword\fP}
.PD
the pattern removal operation is applied to each member of the
array in turn, and the expansion is the resultant list.
.TP
-.PD 0
${\fIparameter\fP\fB%\fP\fIword\fP}
+.PD 0
.TP
${\fIparameter\fP\fB%%\fP\fIword\fP}
.PD
the pattern removal operation is applied to each member of the
array in turn, and the expansion is the resultant list.
.TP
-.PD 0
${\fIparameter\fP\fB/\fP\fIpattern\fP\fB/\fP\fIstring\fP}
-.TP
-${\fIparameter\fP\fB//\fP\fIpattern\fP\fB/\fP\fIstring\fP}
-.PD
The \fIpattern\fP is expanded to produce a pattern just as in
pathname expansion.
\fIParameter\fP is expanded and the longest match of \fIpattern\fP
against its value is replaced with \fIstring\fP.
-In the first form, only the first match is replaced.
-The second form causes all matches of \fIpattern\fP to be
-replaced with \fIstring\fP.
+If \Ipattern\fP begins with \fB/\fP, all matches of \fIpattern\fP are
+replaced with \fIstring\fP. Normally only the first match is replaced.
If \fIpattern\fP begins with \fB#\fP, it must match at the beginning
of the expanded value of \fIparameter\fP.
If \fIpattern\fP begins with \fB%\fP, it must match at the end
inside the parentheses is not treated specially.
All tokens in the expression undergo parameter expansion, string
expansion, command substitution, and quote removal.
-Arithmetic substitutions may be nested.
+Arithmetic expansions may be nested.
.PP
The evaluation is performed according to the rules listed below under
.SM
.B IFS
is null, no word splitting occurs.
.PP
-Explicit null arguments (\^\f3"\^"\fP or \^\f3'\^'\fP\^) are retained.
+Explicit null arguments (\^\f3"\^"\fP or \^\f3\(aq\^\(aq\fP\^) are retained.
Unquoted implicit null arguments, resulting from the expansion of
parameters that have no values, are removed.
If a parameter with no value is expanded within double quotes, a
.B nullglob
option is set, and no matches are found,
the word is removed.
+If the
+.B failglob
+shell option is set, and no matches are found, an error message
+is printed and the command is not executed.
If the shell option
.B nocaseglob
is enabled, the match is performed without regard to the case
for a description of the
.BR nocaseglob ,
.BR nullglob ,
+.BR failglob ,
and
.B dotglob
shell options.
.B ``.''
and
.B ``..''
-are always ignored, even when
+are always ignored when
.SM
.B GLOBIGNORE
-is set. However, setting
+is set and not null. However, setting
.SM
.B GLOBIGNORE
-has the effect of enabling the
+to a non-null value has the effect of enabling the
.B dotglob
shell option, so all other file names beginning with a
.B ``.''
.PP
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. The special pattern characters must be quoted if
+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.
.PP
The special pattern characters have the following meanings:
.TP
.B [...]
Matches any one of the enclosed characters. A pair of characters
-separated by a minus sign denotes a
-.IR range ;
-any character lexically between those two characters, inclusive,
+separated by a hyphen denotes a
+\fIrange expression\fP;
+any character that sorts between those two characters, inclusive,
+using the current locale's collating sequence and character set,
is matched. If the first character following the
.B [
is a
or a
.B ^
then any character not enclosed is matched.
+The sorting order of characters in range expressions is determined by
+the current locale and the value of the \fBLC_COLLATE\fP shell variable,
+if set.
A
.B \-
may be matched by including it as the first or last character
.BR ] ,
\fIcharacter classes\fP can be specified using the syntax
\fB[:\fP\fIclass\fP\fB:]\fP, where \fIclass\fP is one of the
-following classes defined in the POSIX.2 standard:
+following classes defined in the POSIX standard:
.PP
.RS
.B
-.if n alnum alpha ascii blank cntrl digit graph lower print punct space upper xdigit
-.if t alnum alpha ascii blank cntrl digit graph lower print punct space upper xdigit
+.if n alnum alpha ascii blank cntrl digit graph lower print punct space upper word xdigit
+.if t alnum alpha ascii blank cntrl digit graph lower print punct space upper word xdigit
.br
A character class matches any character belonging to that class.
+The \fBword\fP character class matches letters, digits, and the character _.
.br
.if t .sp 0.5
.if n .sp 1
Matches one or more occurrences of the given patterns
.TP
\fB@(\fP\^\fIpattern-list\^\fP\fB)\fP
-Matches exactly one of the given patterns
+Matches one of the given patterns
.TP
\fB!(\fP\^\fIpattern-list\^\fP\fB)\fP
Matches anything except one of the given patterns
After the preceding expansions, all unquoted occurrences of the
characters
.BR \e ,
-.BR ' ,
+.BR \(aq ,
and \^\f3"\fP\^ that did not result from one of the above
expansions are removed.
.SH REDIRECTION
.TP
.B /dev/tcp/\fIhost\fP/\fIport\fP
If \fIhost\fP is a valid hostname or Internet address, and \fIport\fP
-is an integer port number, \fBbash\fP attempts to open a TCP connection
-to the corresponding socket.
+is an integer port number or service name, \fBbash\fP attempts to open
+a TCP connection to the corresponding socket.
.TP
.B /dev/udp/\fIhost\fP/\fIport\fP
If \fIhost\fP is a valid hostname or Internet address, and \fIport\fP
-is an integer port number, \fBbash\fP attempts to open a UDP connection
-to the corresponding socket.
+is an integer port number or service name, \fBbash\fP attempts to open
+a UDP connection to the corresponding socket.
.PD
.RE
.PP
A failure to open or create a file causes the redirection to fail.
+.PP
+Redirections using file descriptors greater than 9 should be used with
+care, as they may conflict with file descriptors the shell uses
+internally.
.SS Redirecting Input
.PP
Redirection of input causes the file whose name results from
the lines read up to that point are then used as the standard
input for a command.
.PP
-The format of here-documents is as follows:
+The format of here-documents is:
.RS
.PP
.nf
\fB<<\fP[\fB\-\fP]\fIword\fP
- \fIhere\-document\fP
+ \fIhere-document\fP
\fIdelimiter\fP
.fi
.RE
This allows
here-documents within shell scripts to be indented in a
natural fashion.
+.SS "Here Strings"
+A variant of here documents, the format is:
+.RS
+.PP
+.nf
+\fB<<<\fP\fIword\fP
+.fi
+.RE
+.PP
+The \fIword\fP is expanded and supplied to the command on its standard
+input.
.SS "Duplicating File Descriptors"
.PP
The redirection operator
As a special case, if \fIn\fP is omitted, and \fIword\fP does not
expand to one or more digits, the standard output and standard
error are redirected as described previously.
+.SS "Moving File Descriptors"
+.PP
+The redirection operator
+.RS
+.PP
+[\fIn\fP]\fB<&\fP\fIdigit\fP\fB\-\fP
+.RE
+.PP
+moves the file descriptor \fIdigit\fP to file descriptor
+.IR n ,
+or the standard input (file descriptor 0) if \fIn\fP is not specified.
+\fIdigit\fP is closed after being duplicated to \fIn\fP.
+.PP
+Similarly, the redirection operator
+.RS
+.PP
+[\fIn\fP]\fB>&\fP\fIdigit\fP\fB\-\fP
+.RE
+.PP
+moves the file descriptor \fIdigit\fP to file descriptor
+.IR n ,
+or the standard output (file descriptor 1) if \fIn\fP is not specified.
.SS "Opening File Descriptors for Reading and Writing"
.PP
The redirection operator
.SM
.B SHELL BUILTIN COMMANDS
below).
-The first word of each command, if unquoted,
+The first word of each simple command, if unquoted,
is checked to see if it has an
alias. If so, that word is replaced by the text of the alias.
-The alias name and the replacement text may contain any valid
-shell input, including the
-.I metacharacters
-listed above, with the exception that the alias name may not
-contain \fI=\fP. The first word of the replacement text is tested
+The characters \fB/\fP, \fB$\fP, \fB`\fP, and \fB=\fP and
+any of the shell \fImetacharacters\fP or quoting characters
+listed above may not appear in an alias name.
+The replacement text may contain any valid shell input,
+including shell metacharacters.
+The first word of the replacement text is tested
for aliases, but a word that is identical to an alias being expanded
-is not expanded a second time. This means that one may alias
+is not expanded a second time.
+This means that one may alias
.B ls
to
.BR "ls \-F" ,
during its execution.
The special parameter
.B #
-is updated to reflect the change. Positional parameter 0
+is updated to reflect the change. Special parameter 0
is unchanged.
-The
+The first element of the
.SM
.B FUNCNAME
variable is set to the name of the function while the function
with the exception that the
.SM
.B DEBUG
-trap (see the description of the
+and
+.B RETURN
+traps (see the description of the
.B trap
builtin under
.SM
.B SHELL BUILTIN COMMANDS
-below) is not inherited.
+below) are not inherited unless the function has been given the
+\fBtrace\fP attribute (see the description of the
+.SM
+.B declare
+builtin below) or the
+\fB\-o functrace\fP shell option has been enabled with
+the \fBset\fP builtin
+(in which case all functions inherit the \fBDEBUG\fP and \fBRETURN\fP traps).
.PP
Variables local to the function may be declared with the
.B local
.B return
is executed in a function, the function completes and
execution resumes with the next command after the function
-call. When a function completes, the values of the
+call.
+Any command associated with the \fBRETURN\fP trap is executed
+before execution resumes.
+When a function completes, the values of the
positional parameters and the special parameter
.B #
are restored to the values they had prior to the function's
.B declare
or
.B typeset
-will list the function names only.
+will list the function names only
+(and optionally the source file and line number, if the \fBextdebug\fP
+shell option is enabled).
Functions may be exported so that subshells
automatically have them defined with the
.B \-f
option to the
.B export
builtin.
+A function definition may be deleted using the \fB\-f\fP option to
+the
+.B unset
+builtin.
+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.
.PP
Functions may be recursive. No limit is imposed on the number
of recursive calls.
.SH "ARITHMETIC EVALUATION"
The shell allows arithmetic expressions to be evaluated, under
-certain circumstances (see the \fBlet\fP builtin command and
-\fBArithmetic Expansion\fP).
-Evaluation is done in long integers with no check for overflow,
+certain circumstances (see the \fBlet\fP and \fBdeclare\fP builtin
+commands and \fBArithmetic Expansion\fP).
+Evaluation is done in fixed-width integers with no check for overflow,
though division by 0 is trapped and flagged as an error.
-The operators and their precedence and associativity are the same
-as in the C language.
+The operators and their precedence, associativity, and values
+are the same as in the C language.
The following list of operators is grouped into levels of
equal-precedence operators.
The levels are listed in order of decreasing precedence.
logical OR
.TP
.B \fIexpr\fP?\fIexpr\fP:\fIexpr\fP
-conditional evaluation
+conditional operator
.TP
.B = *= /= %= += \-= <<= >>= &= ^= |=
assignment
performed before the expression is evaluated.
Within an expression, shell variables may also be referenced by name
without using the parameter expansion syntax.
+A shell variable that is null or unset evaluates to 0 when referenced
+by name without using the parameter expansion syntax.
The value of a variable is evaluated as an arithmetic expression
-when it is referenced.
+when it is referenced, or when a variable which has been given the
+\fIinteger\fP attribute using \fBdeclare -i\fP is assigned a value.
+A null value evaluates to 0.
A shell variable need not have its integer attribute
turned on to be used in an expression.
.PP
base, and \fIn\fP is a number in that base.
If \fIbase#\fP is omitted, then base 10 is used.
The digits greater than 9 are represented by the lowercase letters,
-the uppercase letters, _, and @, in that order.
+the uppercase letters, @, and _, in that order.
If \fIbase\fP is less than or equal to 36, lowercase and uppercase
-letters may be used interchangably to represent numbers between 10
+letters may be used interchangeably to represent numbers between 10
and 35.
.PP
Operators are evaluated in order of precedence. Sub-expressions in
If the \fIfile\fP argument to one of the primaries is one of
\fI/dev/stdin\fP, \fI/dev/stdout\fP, or \fI/dev/stderr\fP, file
descriptor 0, 1, or 2, respectively, is checked.
+.PP
+Unless otherwise specified, primaries that operate on files follow symbolic
+links and operate on the target of the link, rather than the link itself.
.sp 1
.PD 0
.TP
True if \fIfile\fP exists and has been modified since it was last read.
.TP
\fIfile1\fP \-\fBnt\fP \fIfile2\fP
-True if \fIfile1\fP is newer (according to
-modification date) than \fIfile2\fP.
+True if \fIfile1\fP is newer (according to modification date) than \fIfile2\fP,
+or if \fIfile1\fP exists and \fPfile2\fP does not.
.TP
\fIfile1\fP \-\fBot\fP \fIfile2\fP
-True if \fIfile1\fP is older than \fIfile2\fP.
+True if \fIfile1\fP is older than \fIfile2\fP, or if \fIfile2\fP exists
+and \fIfile1\fP does not.
.TP
\fIfile1\fP \fB\-ef\fP \fIfile2\fP
-True if \fIfile1\fP and \fIfile2\fP have the same device and
+True if \fIfile1\fP and \fIfile2\fP refer to the same device and
inode numbers.
.TP
.B \-o \fIoptname\fP
.B \-z \fIstring\fP
True if the length of \fIstring\fP is zero.
.TP
-.B \-n \fIstring\fP
-.TP
\fIstring\fP
+.PD 0
+.TP
+.B \-n \fIstring\fP
+.PD
True if the length of
.I string
is non-zero.
.TP
\fIstring1\fP \fB==\fP \fIstring2\fP
True if the strings are equal. \fB=\fP may be used in place of
-\fB==\fP.
+\fB==\fP for strict POSIX compliance.
.TP
\fIstring1\fP \fB!=\fP \fIstring2\fP
True if the strings are not equal.
.IP \(bu
the file creation mode mask
.IP \(bu
-shell variables marked for export, along with variables exported for
-the command, passed in the environment
+shell variables and functions marked for export, along with variables
+exported for the command, passed in the environment
.IP \(bu
-traps caught by the shell are reset to the values the inherited
-from the shell's parent, and traps ignored by the shell are ignored
+traps caught by the shell are reset to the values inherited from the
+shell's parent, and traps ignored by the shell are ignored
.PP
A command invoked in this separate environment cannot affect the
shell's execution environment.
.PP
-Command substitution and asynchronous commands are invoked in a
+Command substitution, commands grouped with parentheses,
+and asynchronous commands are invoked in a
subshell environment that is a duplicate of the shell environment,
except that traps caught by the shell are reset to the values
that the shell inherited from its parent at invocation. Builtin
commands that are invoked as part of a pipeline are also executed in a
subshell environment. Changes made to the subshell environment
cannot affect the shell's execution environment.
+.PP
+If a command is followed by a \fB&\fP and job control is not active, the
+default standard input for the command is the empty file \fI/dev/null\fP.
+Otherwise, the invoked command inherits the file descriptors of the calling
+shell as modified by redirections.
.SH ENVIRONMENT
When a program is invoked it is given an array of strings
called the
.SM
.BR SIGTSTP .
.PP
-Synchronous jobs started by \fBbash\fP have signal handlers
+Non-builtin commands run by \fBbash\fP have signal handlers
set to the values inherited by the shell from its parent.
When job control is not in effect, asynchronous commands
ignore
and
.SM
.B SIGQUIT
-as well.
+in addition to these inherited handlers.
Commands run as a result of command substitution ignore the
keyboard-generated job control signals
.SM
The shell exits by default upon receipt of a
.SM
.BR SIGHUP .
-Before exiting, it resends the
+Before exiting, an interactive shell resends the
.SM
.B SIGHUP
to all jobs, running or stopped.
.B SIGHUP
to all jobs when an interactive login shell exits.
.PP
-When \fBbash\fP receives a signal for which a trap has been set while
-waiting for a command to complete, the trap will not be executed until
-the command completes.
+If \fBbash\fP 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 command completes.
When \fBbash\fP is waiting for an asynchronous command via the \fBwait\fP
builtin, the reception of a signal for which a trap has been set will
cause the \fBwait\fP builtin to return immediately with an exit status
.BR + ,
and the previous job with a
.BR \- .
+A single % (with no accompanying job specification) also refers to the
+current job.
.PP
Simply naming a job can be used to bring it into the
foreground:
is enabled,
.B bash
reports such changes immediately.
+Any trap on
+.SM
+.B SIGCHLD
+is executed for each child that exits.
.PP
If an attempt to exit
.B bash
.B \ed
the date in "Weekday Month Date" format (e.g., "Tue May 26")
.TP
+.B \eD{\fIformat\fP}
+the \fIformat\fP is passed to \fIstrftime\fP(3) and the result is inserted
+into the prompt string; an empty \fIformat\fP results in a locale-specific
+time representation. The braces are required
+.TP
.B \ee
an ASCII escape character (033)
.TP
.B \e@
the current time in 12-hour am/pm format
.TP
+.B \eA
+the current time in 24-hour HH:MM format
+.TP
.B \eu
the username of the current user
.TP
the version of \fBbash\fP (e.g., 2.00)
.TP
.B \eV
-the release of \fBbash\fP, version + patchlevel (e.g., 2.00.0)
+the release of \fBbash\fP, version + patch level (e.g., 2.00.0)
.TP
.B \ew
-the current working directory
+the current working directory, with \fB$HOME\fP abbreviated with a tilde
.TP
.B \eW
-the basename of the current working directory
+the basename of the current working directory, with \fB$HOME\fP
+abbreviated with a tilde
.TP
.B \e!
the history number of this command
it should be bound. The name may be specified in one of two ways:
as a symbolic key name, possibly with \fIMeta\-\fP or \fIControl\-\fP
prefixes, or as a key sequence.
+.PP
When using the form \fBkeyname\fP:\^\fIfunction\-name\fP or \fImacro\fP,
.I keyname
is the name of a key spelled out in English. For example:
.I C\-o
is bound to run the macro
expressed on the right hand side (that is, to insert the text
-.I "> output"
+.if t \f(CW> output\fP
+.if n ``> output''
into the line).
.PP
In the second form, \fB"keyseq"\fP:\^\fIfunction\-name\fP or \fImacro\fP,
above in that strings denoting
an entire key sequence may be specified by placing the sequence
within double quotes. Some GNU Emacs style key escapes can be
-used, as in the following example.
+used, as in the following example, but the symbolic character names
+are not recognized.
.sp
.RS
"\eC\-u": universal\-argument
and
.I "ESC [ 1 1 ~"
is bound to insert the text
-.BR "Function Key 1" .
+.if t \f(CWFunction Key 1\fP.
+.if n ``Function Key 1''.
+.PP
The full set of GNU Emacs style escape sequences is
.RS
.PD 0
.B \e"
literal "
.TP
-.B \e'
-literal '
+.B \e\(aq
+literal \(aq
.RE
.PD
.PP
vertical tab
.TP
.B \e\fInnn\fP
-the character whose ASCII code is the octal value \fInnn\fP
+the eight-bit character whose value is the octal value \fInnn\fP
(one to three digits)
.TP
-.B \ex\fInnn\fP
-the character whose ASCII code is the hexadecimal value \fInnn\fP
-(one to three digits)
+.B \ex\fIHH\fP
+the eight-bit character whose value is the hexadecimal value \fIHH\fP
+(one or two hex digits)
.RE
.PD
.PP
Unquoted text is assumed to be a function name.
In the macro body, the backslash escapes described above are expanded.
Backslash will quote any other character in the macro text,
-including " and '.
+including " and \(aq.
.PP
.B Bash
allows the current readline key bindings to be displayed or modified
Except where noted, readline variables can take the values
.B On
or
-.BR Off .
+.B Off
+(without regard to case).
+Unrecognized variable names are ignored.
+When a variable value is read, empty or null values, "on" (case-insensitive),
+and "1" are equivalent to \fBOn\fP. All other values are equivalent to
+\fBOff\fP.
The variables and their default values are:
.PP
.PD 0
\fBvisible\fP, readline uses a visible bell if one is available.
If set to \fBaudible\fP, readline attempts to ring the terminal's bell.
.TP
+.B bind\-tty\-special\-chars (On)
+If set to \fBOn\fP, readline attempts to bind the control characters
+treated specially by the kernel's terminal driver to their readline
+equivalents.
+.TP
.B comment\-begin (``#'')
The string that is inserted when the readline
.B insert\-comment
If set to \fBon\fP, tilde expansion is performed when readline
attempts word completion.
.TP
+.B history\-preserve\-point (Off)
+If set to \fBon\fP, the history code attempts to place point at the
+same location on each history line retrieved with \fBprevious-history\fP
+or \fBnext-history\fP.
+.TP
.B horizontal\-scroll\-mode (Off)
When set to \fBOn\fP, makes readline use a single line for display,
scrolling the input horizontally on a single screen line when it
If set to \fBOn\fP, history lines that have been modified are displayed
with a preceding asterisk (\fB*\fP).
.TP
+.B mark\-symlinked\-directories (Off)
+If set to \fBOn\fP, completed names which are symbolic links to directories
+have a slash appended (subject to the value of
+\fBmark\-directories\fP).
+.TP
+.B match\-hidden\-files (On)
+This variable, when set to \fBOn\fP, causes readline to match files whose
+names begin with a `.' (hidden files) when performing filename
+completion, unless the leading `.' is
+supplied by the user in the filename to be completed.
+.TP
.B output\-meta (Off)
If set to \fBOn\fP, readline will display characters with the
eighth bit set directly rather than as a meta-prefixed escape
sequence.
.TP
+.B page\-completions (On)
+If set to \fBOn\fP, readline uses an internal \fImore\fP-like pager
+to display a screenful of possible completions at a time.
+.TP
.B print\-completions\-horizontally (Off)
If set to \fBOn\fP, readline will display completions with matches
sorted horizontally in alphabetical order, rather than down the screen.
words which have more than one possible completion cause the
matches to be listed immediately instead of ringing the bell.
.TP
+.B show\-all\-if\-unmodified (Off)
+This alters the default behavior of the completion functions in
+a fashion similar to \fBshow\-all\-if\-ambiguous\fP.
+If set to
+.BR on ,
+words which have more than one possible completion without any
+possible partial completion (the possible completions don't share
+a common prefix) cause the matches to be listed immediately instead
+of ringing the bell.
+.TP
.B visible\-stats (Off)
If set to \fBOn\fP, a character denoting a file's type as reported
by \fIstat\fP(2) is appended to the filename when listing possible
For instance, a \fInewline\fP will terminate the search and accept
the line, thereby executing the command from the history list.
.PP
+Readline remembers the last incremental search string. If two
+Control-Rs are typed without any intervening characters defining a
+new search string, any remembered search string is used.
+.PP
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.
.TP
.B yank\-nth\-arg (M\-C\-y)
Insert the first argument to the previous command (usually
-the second word on the previous line) at point (the current
-cursor position). With an argument
+the second word on the previous line) at point.
+With an argument
.IR n ,
insert the \fIn\fPth word from the previous command (the words
in the previous command begin with word 0). A negative argument
inserts the \fIn\fPth word from the end of the previous command.
+Once the argument \fIn\fP is computed, the argument is extracted
+as if the "!\fIn\fP" history expansion had been specified.
.TP
.B
yank\-last\-arg (M\-.\^, M\-_\^)
behave exactly like \fByank\-nth\-arg\fP.
Successive calls to \fByank\-last\-arg\fP move back through the history
list, inserting the last argument of each line in turn.
+The history expansion facilities are used to extract the last argument,
+as if the "!$" history expansion had been specified.
.TP
.B shell\-expand\-line (M\-C\-e)
Expand the line as the shell does. This
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.
+.TP
+.B edit\-and\-execute\-command (C\-xC\-e)
+Invoke an editor on the current command line, and execute the result as shell
+commands.
+\fBBash\fP attempts to invoke
+.SM
+.BR $FCEDIT ,
+.SM
+.BR $EDITOR ,
+and \fIemacs\fP as the editor, in that order.
.PD
.SS Commands for Changing Text
.PP
.PD 0
.TP
.B delete\-char (C\-d)
-Delete the character under the cursor. If point is at the
+Delete the character at point. If point is at the
beginning of the line, there are no characters in the line, and
the last character typed was not bound to \fBdelete\-char\fP,
then return
.B forward\-backward\-delete\-char
Delete the character under the cursor, unless the cursor is at the
end of the line, in which case the character behind the cursor is
-deleted. By default, this is not bound to a key.
+deleted.
.TP
.B quoted\-insert (C\-q, C\-v)
Add the next character typed to the line verbatim. This is
Insert the character typed.
.TP
.B transpose\-chars (C\-t)
-Drag the character before point forward over the character at point.
-Point moves forward as well.
-If point is at the end of the line, then transpose the two characters
-before point.
+Drag the character before point forward over the character at point,
+moving point forward as well.
+If point is at the end of the line, then this transposes
+the two characters before point.
Negative arguments have no effect.
.TP
.B transpose\-words (M\-t)
Drag the word before point past the word after point,
-moving the point over that word as well.
+moving point over that word as well.
+If point is at the end of the line, this transposes
+the last two words on the line.
.TP
.B upcase\-word (M\-u)
Uppercase the current (or following) word. With a negative argument,
.B capitalize\-word (M\-c)
Capitalize the current (or following) word. With a negative argument,
capitalize the previous word, but do not move point.
+.TP
+.B overwrite\-mode
+Toggle overwrite mode. With an explicit positive numeric argument,
+switches to overwrite mode. With an explicit non-positive numeric
+argument, switches to insert mode. This command affects only
+\fBemacs\fP mode; \fBvi\fP mode does overwrite differently.
+Each call to \fIreadline()\fP starts in insert mode.
+In overwrite mode, characters bound to \fBself\-insert\fP replace
+the text at point rather than pushing the text to the right.
+Characters bound to \fBbackward\-delete\-char\fP replace the character
+before point with a space. By default, this command is unbound.
.PD
.SS Killing and Yanking
.PP
.TP
.B unix\-word\-rubout (C\-w)
Kill the word behind point, using white space as a word boundary.
-The word boundaries are different from \fBbackward\-kill\-word\fP.
+The killed text is saved on the kill-ring.
+.TP
+.B unix\-filename\-rubout
+Kill the word behind point, using white space and the slash character
+as the word boundaries.
The killed text is saved on the kill-ring.
.TP
.B delete\-horizontal\-space (M\-\e)
The word boundaries are the same as \fBforward\-word\fP.
.TP
.B yank (C\-y)
-Yank the top of the kill ring into the buffer at the cursor.
+Yank the top of the kill ring into the buffer at point.
.TP
.B yank\-pop (M\-y)
Rotate the kill ring, and yank the new top. Only works following
with a single match from the list of possible completions.
Repeated execution of \fBmenu\-complete\fP steps through the list
of possible completions, inserting each match in turn.
-At the end of the list of completions, the bell is rung and the
-original text is restored.
+At the end of the list of completions, the bell is rung
+(subject to the setting of \fBbell\-style\fP)
+and the original text is restored.
An argument of \fIn\fP moves \fIn\fP positions forward in the list
of matches; a negative argument may be used to move backward
through the list.
Perform tilde expansion on the current word.
.TP
.B set\-mark (C\-@, M\-<space>)
-Set the mark to the current point. If a
+Set the mark to the point. If a
numeric argument is supplied, the mark is set to that position.
.TP
.B exchange\-point\-and\-mark (C\-x C\-x)
character. A negative count searches for subsequent occurrences.
.TP
.B insert\-comment (M\-#)
-The value of the readline
+Without a numeric argument, the value of the readline
.B comment\-begin
-variable is inserted at the beginning of the current line, and the line
-is accepted as if a newline had been typed. The default value of
+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 \fBcomment\-begin\fP, the value is inserted, otherwise
+the characters in \fBcomment-begin\fP are deleted from the beginning of
+the line.
+In either case, the line is accepted as if a newline had been typed.
+The default value of
\fBcomment\-begin\fP 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.
+.TP
+.B glob\-complete\-word (M\-g)
+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 file names for possible completions.
.TP
.B glob\-expand\-word (C\-x *)
The word before point is treated as a pattern for pathname expansion,
and the list of matching file names is inserted, replacing the word.
+If a numeric argument is supplied, an asterisk is appended before
+pathname expansion.
.TP
.B glob\-list\-expansions (C\-x g)
The list of expansions that would have been generated by
.B glob\-expand\-word
is displayed, and the line is redrawn.
+If a numeric argument is supplied, an asterisk is appended before
+pathname expansion.
.TP
.B dump\-functions
Print all of the functions and their key bindings to the
.TP
.B dump\-macros
Print all of the readline key sequences bound to macros and the
-strings they ouput. If a numeric argument is supplied,
+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 \fIinputrc\fP file.
.TP
Shell quoting is honored.
Each word is then expanded using
brace expansion, tilde expansion, parameter and variable expansion,
-command substitution, arithmetic expansion, and pathname expansion,
+command substitution, and arithmetic expansion,
as described above under
.SM
.BR EXPANSION .
returned to the readline completion code as the list of possible
completions.
.PP
-If a compspec is found, whatever it generates is returned to the completion
-code as the full set of possible completions.
+If the previously-applied actions do not generate any matches, and the
+\fB\-o dirnames\fP option was supplied to \fBcomplete\fP when the
+compspec was defined, directory name completion is attempted.
+.PP
+If the \fB\-o plusdirs\fP option was supplied to \fBcomplete\fP when the
+compspec was defined, directory name completion is attempted and any
+matches are added to the results of the other actions.
+.PP
+By default, if a compspec is found, whatever it generates is returned
+to the completion code as the full set of possible completions.
The default \fBbash\fP completions are not attempted, and the readline
default of filename completion is disabled.
+If the \fB\-o bashdefault\fP option was supplied to \fBcomplete\fP when
+the compspec was defined, the \fBbash\fP default completions are attempted
+if the compspec generates no matches.
+If the \fB\-o default\fP option was supplied to \fBcomplete\fP when the
+compspec was defined, readline's default completion will be performed
+if the compspec (and, if attempted, the default \fBbash\fP completions)
+generate no matches.
+.PP
+When a compspec indicates that directory name completion is desired,
+the programmable completion functions force readline to append a slash
+to completed names which are symbolic links to directories, subject to
+the value of the \fBmark\-directories\fP readline variable, regardless
+of the setting of the \fBmark-symlinked\-directories\fP readline variable.
.SH HISTORY
When the
.B \-o history
Only backslash (\^\fB\e\fP\^) and single quotes can quote
the history expansion character.
.PP
+Several characters inhibit history expansion if found immediately
+following the history expansion character, even if it is unquoted:
+space, tab, newline, carriage return, and \fB=\fP.
+If the \fBextglob\fP shell option is enabled, \fB(\fP will also
+inhibit expansion.
+.PP
Several shell options settable with the
.B shopt
builtin may be used to tailor the behavior of history expansion.
.B !
Start a history substitution, except when followed by a
.BR blank ,
-newline, = or (.
+newline, carriage return, =
+or ( (when the \fBextglob\fP shell option is enabled using
+the \fBshopt\fP builtin).
.TP
.B !\fIn\fR
Refer to command line
`\fB:s\fP', 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 \fBa\fP may be used as a synonym for \fBg\fP.
+.TP
+.B G
+Apply the following `\fBs\fP' modifier once to each word in the event line.
.PD
.SH "SHELL BUILTIN COMMANDS"
.\" start of bash_builtins
accepts
.B \-\-
to signify the end of the options.
+For example, the \fB:\fP, \fBtrue\fP, \fBfalse\fP, and \fBtest\fP builtins
+do not accept options.
.sp .5
.PD 0
.TP
and performing any specified
redirections. A zero exit code is returned.
.TP
-.PD 0
\fB .\| \fP \fIfilename\fP [\fIarguments\fP]
+.PD 0
.TP
\fBsource\fP \fIfilename\fP [\fIarguments\fP]
.PD
The file searched for in
.SM
.B PATH
-need not be executable. The current directory is
+need not be executable.
+When \fBbash\fP is not in \fIposix mode\fP, the current directory is
searched if no file is found in
.SM
.BR PATH .
\fBAlias\fP returns true unless a \fIname\fP is given for which
no alias has been defined.
.TP
-\fBbg\fP [\fIjobspec\fP]
-Resume the suspended job \fIjobspec\fP in the background, as if it
+\fBbg\fP [\fIjobspec\fP ...]
+Resume each suspended job \fIjobspec\fP in the background, as if it
had been started with
.BR & .
If \fIjobspec\fP is not present, the shell's notion of the
.B bg
.I jobspec
returns 0 unless run when job control is disabled or, when run with
-job control enabled, if \fIjobspec\fP was not found or started without
-job control.
+job control enabled, any specified \fIjobspec\fP was not found
+or was started without job control.
.TP
-.PD 0
\fBbind\fP [\fB\-m\fP \fIkeymap\fP] [\fB\-lpsvPSV\fP]
+.PD 0
.TP
\fBbind\fP [\fB\-m\fP \fIkeymap\fP] [\fB\-q\fP \fIfunction\fP] [\fB\-u\fP \fIfunction\fP] [\fB\-r\fP \fIkeyseq\fP]
.TP
\fBbind\fP [\fB\-m\fP \fIkeymap\fP] \fB\-x\fP \fIkeyseq\fP:\fIshell\-command\fP
.TP
\fBbind\fP [\fB\-m\fP \fIkeymap\fP] \fIkeyseq\fP:\fIfunction\-name\fP
+.TP
+\fBbind\fP \fIreadline\-command\fP
.PD
Display current
.B readline
-key and function bindings, or bind a key sequence to a
+key and function bindings, bind a key sequence to a
+.B readline
+function or macro, or set a
.B readline
-function or macro. The binding syntax accepted is identical to that of
+variable.
+Each non-option argument is a command as it would appear in
.IR .inputrc ,
-but each binding must be passed as a separate argument;
-e.g., '"\eC\-x\eC\-r": re\-read\-init\-file'. Options, if supplied, have the
-following meanings:
+but each binding or command must be passed as a separate argument;
+e.g., '"\eC\-x\eC\-r": re\-read\-init\-file'.
+Options, if supplied, have the following meanings:
.RS
.PD 0
.TP
.I keymap
names are
\fIemacs, emacs\-standard, emacs\-meta, emacs\-ctlx, vi,
-vi\-command\fP, and
+vi\-move, vi\-command\fP, and
.IR vi\-insert .
\fIvi\fP is equivalent to \fIvi\-command\fP; \fIemacs\fP is
equivalent to \fIemacs\-standard\fP.
.I shell\-builtin
is not a shell builtin command.
.TP
-\fBcd\fP [\fB\-LP\fP] [\fIdir\fP]
+\fBcd\fP [\fB\-L|-P\fP] [\fIdir\fP]
Change the current directory to \fIdir\fP. The variable
.SM
.B HOME
is equivalent to
.SM
.BR $OLDPWD .
+If a non-empty directory name from \fBCDPATH\fP is used, or if
+\fB\-\fP 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 changed;
false otherwise.
.TP
+\fBcaller\fP [\fIexpr\fP]
+Returns the context of any active subroutine call (a shell function or
+a script executed with the \fB.\fP or \fBsource\fP builtins.
+Without \fIexpr\fP, \fBcaller\fP displays the line number and source
+filename of the current subroutine call.
+If a non-negative integer is supplied as \fIexpr\fP, \fBcaller\fP
+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 subroutine
+call or \fIexpr\fP does not correspond to a valid position in the
+call stack.
+.TP
\fBcommand\fP [\fB\-pVv\fP] \fIcommand\fP [\fIarg\fP ...]
Run
.I command
The return value is true unless an invalid option is supplied, or no
matches were generated.
.TP
-.PD 0
-\fBcomplete\fP [\fB\-abcdefjkvu\fP] [\fB\-A\fP \fIaction\fP] [\fB\-G\fP \fIglobpat\fP] [\fB\-W\fP \fIwordlist\fP] [\fB\-P\fP \fIprefix\fP] [\fB\-S\fP \fIsuffix\fP]
+\fBcomplete\fP [\fB\-abcdefgjksuv\fP] [\fB\-o\fP \fIcomp-option\fP] [\fB\-A\fP \fIaction\fP] [\fB\-G\fP \fIglobpat\fP] [\fB\-W\fP \fIwordlist\fP] [\fB\-P\fP \fIprefix\fP] [\fB\-S\fP \fIsuffix\fP]
.br
[\fB\-X\fP \fIfilterpat\fP] [\fB\-F\fP \fIfunction\fP] [\fB\-C\fP \fIcommand\fP] \fIname\fP [\fIname ...\fP]
+.PD 0
.TP
\fBcomplete\fP \fB\-pr\fP [\fIname\fP ...]
.PD
.RS
.PD 0
.TP 8
+\fB\-o\fP \fIcomp-option\fP
+The \fIcomp-option\fP controls several aspects of the compspec's behavior
+beyond the simple generation of completions.
+\fIcomp-option\fP may be one of:
+.RS
+.TP 8
+.B bashdefault
+Perform the rest of the default \fBbash\fP completions if the compspec
+generates no matches.
+.TP 8
+.B default
+Use readline's default filename completion if the compspec generates
+no matches.
+.TP 8
+.B dirnames
+Perform directory name completion if the compspec generates no matches.
+.TP 8
+.B filenames
+Tell readline that the compspec generates filenames, so it can perform any
+filename\-specific processing (like adding a slash to directory names or
+suppressing trailing spaces). Intended to be used with shell functions.
+.TP 8
+.B nospace
+Tell readline not to append a space (the default) to words completed at
+the end of the line.
+.TP 8
+.B plusdirs
+After any matches defined by the compspec are generated,
+directory name completion is attempted and any
+matches are added to the results of the other actions.
+.RE
+.TP 8
\fB\-A\fP \fIaction\fP
The \fIaction\fP may be one of the following to generate a list of possible
completions:
.B function
Names of shell functions.
.TP 8
+.B group
+Group names. May also be specified as \fB\-g\fP.
+.TP 8
.B helptopic
Help topics as accepted by the \fBhelp\fP builtin.
.TP 8
.B running
Names of running jobs, if job control is active.
.TP 8
+.B service
+Service names. May also be specified as \fB\-s\fP.
+.TP 8
.B setopt
Valid arguments for the \fB\-o\fP option to the \fBset\fP builtin.
.TP 8
.B continue
is executed.
.TP
+\fBdeclare\fP [\fB\-afFirtx\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] ...]
.PD 0
-\fBdeclare\fP [\fB\-afFirx\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP]]
.TP
-\fBtypeset\fP [\fB\-afFirx\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP]]
+\fBtypeset\fP [\fB\-afFirtx\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] ...]
.PD
Declare variables and/or give them attributes.
If no \fIname\fPs are given then display the values of variables.
.B \-F
option inhibits the display of function definitions; only the
function name and attributes are printed.
-The
+If the \fBextdebug\fP shell option is enabled using \fBshopt\fP,
+the source file name and line number where the function is defined
+are displayed as well. The
.B \-F
option implies
.BR \-f .
Make \fIname\fPs readonly. These names cannot then be assigned values
by subsequent assignment statements or unset.
.TP
+.B \-t
+Give each \fIname\fP the \fItrace\fP attribute.
+Traced functions inherit the \fBDEBUG\fP and \fBRETURN\fP traps from
+the calling shell.
+The trace attribute has no special meaning for variables.
+.TP
.B \-x
Mark \fIname\fPs for export to subsequent commands via the environment.
.PD
makes each
\fIname\fP local, as with the
.B local
-command. The return value is 0 unless an invalid option is encountered,
+command.
+If a variable name is followed by =\fIvalue\fP, the value of
+the variable is set to \fIvalue\fP.
+The return value is 0 unless an invalid option is encountered,
an attempt is made to define a function using
.if n ``\-f foo=bar'',
.if t \f(CW\-f foo=bar\fP,
.B \-E
option disables the interpretation of these escape characters,
even on systems where they are interpreted by default.
-The \fBxpg_echo\fP shell option to the may be used to
+The \fBxpg_echo\fP shell option may be used to
dynamically determine whether or not \fBecho\fP expands these
escape characters by default.
.B echo
-does not interpret
-.B \-\-
-to mean the end of options.
+does not interpret \fB\-\-\fP to mean the end of options.
.B echo
interprets the following escape sequences:
.RS
.B \e\e
backslash
.TP
-.B \e\fInnn\fP
-the character whose ASCII code is the octal value \fInnn\fP
-(one to three digits)
+.B \e0\fInnn\fP
+the eight-bit character whose value is the octal value \fInnn\fP
+(zero to three octal digits)
.TP
-.B \ex\fInnn\fP
-the character whose ASCII code is the hexadecimal value \fInnn\fP
-(one to three digits)
+.B \ex\fIHH\fP
+the eight-bit character whose value is the hexadecimal value \fIHH\fP
+(one or two hex digits)
.PD
.RE
.TP
.SM
.B PATH
instead of the shell builtin version, run
-\f(CWenable -n test\fP.
+.if t \f(CWenable -n test\fP.
+.if n ``enable -n test''.
The
.B \-f
option means to load the new builtin command
.B EXIT
is executed before the shell terminates.
.TP
-.PD 0
\fBexport\fP [\fB\-fn\fP\^] [\fIname\fP[=\fIword\fP]] ...
+.PD 0
.TP
.B export \-p
.PD
of all names that are exported in this shell is printed.
The
.B \-n
-option causes the export property to be removed from the
-named variables.
+option causes the export property to be removed from each
+\fIname\fP.
+If a variable name is followed by =\fIword\fP, the value of
+the variable is set to \fIword\fP.
.B export
returns an exit status of 0 unless an invalid option is
encountered,
.I name
that is not a function.
.TP
-.PD 0
\fBfc\fP [\fB\-e\fP \fIename\fP] [\fB\-nlr\fP] [\fIfirst\fP] [\fIlast\fP]
+.PD 0
.TP
\fBfc\fP \fB\-s\fP [\fIpat\fP=\fIrep\fP] [\fIcmd\fP]
.PD
In the second form, \fIcommand\fP is re-executed after each instance
of \fIpat\fP is replaced by \fIrep\fP.
A useful alias to use with this is
-.if n ``r=fc -s'',
+.if n ``r="fc -s"'',
.if t \f(CWr='fc \-s'\fP,
so that typing
.if n ``r cc''
is not silent,
a question mark (\^\fB?\fP\^) is placed in
.IR name ,
+.SM
.B OPTARG
is unset, and a diagnostic message is printed.
If
It returns false if the end of options is encountered or an
error occurs.
.TP
-\fBhash\fP [\fB\-r\fP] [\fB\-p\fP \fIfilename\fP] [\fIname\fP]
+\fBhash\fP [\fB\-lr\fP] [\fB\-p\fP \fIfilename\fP] [\fB\-dt\fP] [\fIname\fP]
For each
.IR name ,
the full file name of the command is determined by searching
The
.B \-r
option causes the shell to forget all
-remembered locations. If no arguments are given, information
-about remembered commands is printed.
+remembered locations.
+The
+.B \-d
+option causes the shell to forget the remembered location of each \fIname\fP.
+If the
+.B \-t
+option is supplied, the full pathname to which each \fIname\fP corresponds
+is printed. If multiple \fIname\fP arguments are supplied with \fB\-t\fP,
+the \fIname\fP is printed before the hashed full pathname.
+The
+.B \-l
+option causes output to be displayed in a format that may be reused as input.
+If no arguments are given, or if only \fB\-l\fP is supplied,
+information about remembered commands is printed.
The return status is true unless a
.I name
is not found or an invalid option is supplied.
The return status is 0 unless no command matches
.IR pattern .
.TP
-.PD 0
\fBhistory [\fIn\fP]
+.PD 0
.TP
\fBhistory\fP \fB\-c\fP
.TP
.I n
lists only the last
.I n
-lines. If \fIfilename\fP is supplied, it is used as the
+lines.
+If the shell variable \fBHISTTIMEFORMAT\fP is set and not null,
+it is used as a format string for \fIstrftime\fP(3) to display
+the time stamp associated with each displayed history entry.
+No intervening blank is printed between the formatted time stamp
+and the history line.
+If \fIfilename\fP is supplied, it is used as the
name of the history file; if not, the value of
.SM
.B HISTFILE
are added.
.PD
.PP
+If the \fBHISTTIMEFORMAT\fP is set, the time stamp information
+associated with each history entry is written to the history file.
The return value is 0 unless an invalid option is encountered, an
error occurs while reading or writing the history file, an invalid
\fIoffset\fP is supplied as an argument to \fB\-d\fP, or the
history expansion supplied as an argument to \fB\-p\fP fails.
.RE
.TP
-.PD 0
\fBjobs\fP [\fB\-lnprs\fP] [ \fIjobspec\fP ... ]
+.PD 0
.TP
\fBjobs\fP \fB\-x\fP \fIcommand\fP [ \fIargs\fP ... ]
.PD
returning its exit status.
.RE
.TP
-.PD 0
\fBkill\fP [\fB\-s\fP \fIsigspec\fP | \fB\-n\fP \fIsignum\fP | \fB\-\fP\fIsigspec\fP] [\fIpid\fP | \fIjobspec\fP] ...
+.PD 0
.TP
\fBkill\fP \fB\-l\fP [\fIsigspec\fP | \fIexit_status\fP]
.PD
or
.IR jobspec .
.I sigspec
-is either a signal name such as
+is either a case-insensitive signal name such as
.SM
.B SIGKILL
-or a signal number;
-.I signum
-is a signal number. If
-.I sigspec
-is a signal name, the name may be
-given with or without the
+(with or without the
.SM
.B SIG
-prefix.
+prefix) or a signal number;
+.I signum
+is a signal number.
If
.I sigspec
is not present, then
directory change fails.
.RE
.TP
-\fBprintf\fP \fIformat\fP [\fIarguments\fP]
+\fBprintf\fP [\fB\-v\fP \fIvar\fP] \fIformat\fP [\fIarguments\fP]
Write the formatted \fIarguments\fP to the standard output under the
control of the \fIformat\fP.
The \fIformat\fP is a character string which contains three types of objects:
escape sequences, which are converted and copied to the standard output, and
format specifications, each of which causes printing of the next successive
\fIargument\fP.
-In addition to the standard \fIprintf\fP(1) formats, %b causes
+In addition to the standard \fIprintf\fP(1) formats, \fB%b\fP causes
\fBprintf\fP to expand backslash escape sequences in the corresponding
-\fIargument\fP, and %q causes \fBprintf\fP to output the corresponding
+\fIargument\fP (except that \fB\ec\fP terminates output, backslashes in
+\fB\e\(aq\fP, \fB\e"\fP, and \fB\e?\fP are not removed, and octal escapes
+beginning with \fB\e0\fP may contain up to four digits),
+and \fB%q\fP causes \fBprintf\fP to output the corresponding
\fIargument\fP in a format that can be reused as shell input.
.sp 1
+The \fB\-v\fP option causes the output to be assigned to the variable
+\fIvar\fP rather than being printed to the standard output.
+.sp 1
The \fIformat\fP is reused as necessary to consume all of the \fIarguments\fP.
If the \fIformat\fP requires more \fIarguments\fP than are supplied, 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.
.TP
-.PD 0
\fBpushd\fP [\fB\-n\fP] [\fIdir\fP]
+.PD 0
.TP
\fBpushd\fP [\fB\-n\fP] [+\fIn\fP] [\-\fIn\fP]
.PD
reading the name of the current directory or an
invalid option is supplied.
.TP
-\fBread\fP [\fB\-ers\fP] [\fB\-t\fP \fItimeout\fP] [\fB\-a\fP \fIaname\fP] [\fB\-p\fP \fIprompt\fP] [\fB\-n\fP \fInchars\fP] [\fB\-d\fP \fIdelim\fP] [\fIname\fP ...]
-One line is read from the standard input, and the first word
+\fBread\fP [\fB\-ers\fP] [\fB\-u\fP \fIfd\fP] [\fB\-t\fP \fItimeout\fP] [\fB\-a\fP \fIaname\fP] [\fB\-p\fP \fIprompt\fP] [\fB\-n\fP \fInchars\fP] [\fB\-d\fP \fIdelim\fP] [\fIname\fP ...]
+One line is read from the standard input, or from the file descriptor
+\fIfd\fP supplied as an argument to the \fB\-u\fP option, and the first word
is assigned to the first
.IR name ,
the second word to the second
and so on, with leftover words and their intervening separators assigned
to the last
.IR name .
-If there are fewer words read from the standard input than names,
+If there are fewer words read from the input stream than names,
the remaining names are assigned empty values.
The characters in
.SM
waiting for a complete line of input.
.TP
.B \-p \fIprompt\fP
-Display \fIprompt\fP, without a
+Display \fIprompt\fP on standard error, without a
trailing newline, before attempting to read any input. The prompt
is displayed only if input is coming from a terminal.
.TP
input is not read within \fItimeout\fP seconds.
This option has no effect if \fBread\fP is not reading input from the
terminal or a pipe.
+.TP
+.B \-u \fIfd\fP
+Read input from file descriptor \fIfd\fP.
.PD
.PP
If no
are supplied, the line read is assigned to the variable
.SM
.BR REPLY .
-The return code is zero, unless end-of-file is encountered or \fBread\fP
-times out.
+The return code is zero, unless end-of-file is encountered, \fBread\fP
+times out, or an invalid file descriptor is supplied as the argument to
+\fB\-u\fP.
.RE
.TP
-\fBreadonly\fP [\fB\-apf\fP] [\fIname\fP ...]
+\fBreadonly\fP [\fB\-apf\fP] [\fIname\fP[=\fIword\fP] ...]
.PD
The given
\fInames\fP are marked readonly; the values of these
.B \-p
option causes output to be displayed in a format that
may be reused as input.
+If a variable name is followed by =\fIword\fP, the value of
+the variable is set to \fIword\fP.
The return status is 0 unless an invalid option is encountered,
one of the
.I names
script as the exit status of the script. If used outside a
function and not during execution of a script by \fB.\fP\^,
the return status is false.
+Any command associated with the \fBRETURN\fP trap is executed
+before execution resumes after the function or script.
.TP
\fBset\fP [\fB\-\-abefhkmnptuvxBCHP\fP] [\fB\-o\fP \fIoption\fP] [\fIarg\fP ...]
Without options, the name and value of each shell variable are displayed
-in a format that can be reused as input.
+in a format that can be reused as input
+for setting or resetting the currently-set variables.
+Read-only variables cannot be reset.
+In \fIposix mode\fP, 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 the options are processed are treated
.PD 0
.TP 8
.B \-a
-Automatically mark variables which are modified or created for export
-to the environment of subsequent commands.
+Automatically mark variables and functions which are modified or
+created for export to the environment of subsequent commands.
.TP 8
.B \-b
Report the status of terminated background jobs
Exit immediately if a \fIsimple command\fP (see
.SM
.B SHELL GRAMMAR
-above) exits with a non-zero status. The shell does not exit if the
-command that fails is part of an
-.I until
+above) exits with a non-zero status.
+The shell does not exit if the
+command that fails is part of the command list immediately following a
+.B while
or
-.I while
-loop,
-part of an
+.B until
+keyword,
+part of the test in an
.I if
statement, part of a
.B &&
list, or if the command's return value is
being inverted via
.BR ! .
+A trap on \fBERR\fP, if set, is executed before the shell exits.
.TP 8
.B \-f
Disable pathname expansion.
.B \-\-noediting
option.
.TP 8
+.B errtrace
+Same as
+.BR \-E .
+.TP 8
+.B functrace
+Same as
+.BR \-T .
+.TP 8
.B errexit
Same as
.BR \-e .
This option is on by default in interactive shells.
.TP 8
.B ignoreeof
-The effect is as if the shell command \f(CWIGNOREEOF=10\fP had been executed
+The effect is as if the shell command
+.if t \f(CWIGNOREEOF=10\fP
+.if n ``IGNOREEOF=10''
+had been executed
(see
.B Shell Variables
above).
.B noglob
Same as
.BR \-f .
+.B nolog
+Currently ignored.
.TP 8
.B notify
Same as
Same as
.BR \-P .
.TP 8
+.B pipefail
+If set, the return value of a pipeline is the value of the last
+(rightmost) command to exit with a non-zero status, or zero if all
+commands in the pipeline exit successfully.
+This option is disabled by default.
+.TP 8
.B posix
Change the behavior of
.B bash
where the default operation differs
-from the POSIX 1003.2 standard to match the standard.
+from the POSIX standard to match the standard (\fIposix mode\fP).
.TP 8
.B privileged
Same as
.TP 8
.B \-x
After expanding each \fIsimple command\fP,
-display the expanded value of
+\fBfor\fP command, \fBcase\fP command, \fBselect\fP command, or
+arithmetic \fBfor\fP command, display the expanded value of
.SM
.BR PS4 ,
-followed by the command and its expanded arguments.
+followed by the command and its expanded arguments
+or associated word list.
.TP 8
.B \-B
The shell performs brace expansion (see
instead of
.BR > .
.TP 8
+.B \-E
+If set, any trap on \fBERR\fP is inherited by shell functions, command
+substitutions, and commands executed in a subshell environment.
+The \fBERR\fP trap is normally not inherited in such cases.
+.TP 8
.B \-H
Enable
.B !
follows the logical chain of directories when performing commands
which change the current directory.
.TP 8
+.B \-T
+If set, any traps on \fBDEBUG\fP and \fBRETURN\fP are inherited by shell
+functions, command substitutions, and commands executed in a
+subshell environment.
+The \fBDEBUG\fP and \fBRETURN\fP traps are normally not inherited
+in such cases.
+.TP 8
.B \-\-
If no arguments follow this option, then the positional parameters are
unset. Otherwise, the positional parameters are set to the
command in the same history entry. This allows
easy re-editing of multi-line commands.
.TP 8
+.B compat31
+If set,
+.B bash
+changes its behavior to that of version 3.1 with respect to quoted
+arguments to the conditional command's =~ operator.
+.TP 8
.B dotglob
If set,
.B bash
.BR ALIASES .
This option is enabled by default for interactive shells.
.TP 8
+.B extdebug
+If set, behavior intended for use by debuggers is enabled:
+.RS
+.TP
+.B 1.
+The \fB\-F\fP option to the \fBdeclare\fP builtin displays the source
+file name and line number corresponding to each function name supplied
+as an argument.
+.TP
+.B 2.
+If the command run by the \fBDEBUG\fP trap returns a non-zero value, the
+next command is skipped and not executed.
+.TP
+.B 3.
+If the command run by the \fBDEBUG\fP trap returns a value of 2, and the
+shell is executing in a subroutine (a shell function or a shell script
+executed by the \fB.\fP or \fBsource\fP builtins), a call to
+\fBreturn\fP is simulated.
+.TP
+.B 4.
+\fBBASH_ARGC\fP and \fBBASH_ARGV\fP are updated as described in their
+descriptions above.
+.TP
+.B 5.
+Function tracing is enabled: command substitution, shell functions, and
+subshells invoked with \fB(\fP \fIcommand\fP \fB)\fP inherit the
+\fBDEBUG\fP and \fBRETURN\fP traps.
+.TP
+.B 6.
+Error tracing is enabled: command substitution, shell functions, and
+subshells invoked with \fB(\fP \fIcommand\fP \fB)\fP inherit the
+\fBERROR\fP trap.
+.RE
+.TP 8
.B extglob
If set, the extended pattern matching features described above under
\fBPathname Expansion\fP are enabled.
.TP 8
+.B extquote
+If set, \fB$\fP\(aq\fIstring\fP\(aq and \fB$\fP"\fIstring\fP" quoting is
+performed within \fB${\fP\fIparameter\fP\fB}\fP expansions
+enclosed in double quotes. This option is enabled by default.
+.TP 8
+.B failglob
+If set, patterns which fail to match filenames during pathname expansion
+result in an expansion error.
+.TP 8
+.B force_fignore
+If set, the suffixes specified by the \fBFIGNORE\fP shell variable
+cause words to be ignored when performing word completion even if
+the ignored words are the only possible completions.
+See
+.SM
+\fBSHELL VARIABLES\fP
+above for a description of \fBFIGNORE\fP.
+This option is enabled by default.
+.TP 8
+.B gnu_errfmt
+If set, shell error messages are written in the standard GNU error
+message format.
+.TP 8
.B histappend
If set, the history list is appended to the file named by the value
of the
option is enabled, multi-line commands are saved to the history with
embedded newlines rather than using semicolon separators where possible.
.TP 8
+.B login_shell
+The shell sets this option if it is started as a login shell (see
+.SM
+.B "INVOCATION"
+above).
+The value may not be changed.
+.TP 8
.B mailwarn
If set, and a file that \fBbash\fP is checking for mail has been
accessed since the last time it was checked, the message ``The mail in
.B Pathname Expansion
above).
.TP 8
+.B nocasematch
+If set,
+.B bash
+matches patterns in a case\-insensitive fashion when performing matching
+while executing \fBcase\fP or \fB[[\fP conditional commands.
+.TP 8
.B nullglob
If set,
.B bash
This option is enabled by default.
.TP 8
.B promptvars
-If set, prompt strings undergo variable and parameter expansion after
-being expanded as described in
+If set, prompt strings undergo
+parameter expansion, command substitution, arithmetic
+expansion, and quote removal after being expanded as described in
.SM
.B PROMPTING
above. This option is enabled by default.
.B \-f
is not supplied, or if job control is not enabled.
.TP
-.PD 0
\fBtest\fP \fIexpr\fP
+.PD 0
.TP
\fB[\fP \fIexpr\fP \fB]\fP
Return a status of 0 or 1 depending on
Expressions are composed of the primaries described above under
.SM
.BR "CONDITIONAL EXPRESSIONS" .
+\fBtest\fP does not accept any options, nor does it accept and ignore
+an argument of \fB\-\-\fP as signifying the end of options.
.if t .sp 0.5
.if n .sp 1
Expressions may be combined using the following operators, listed
Print the accumulated user and system times for the shell and
for processes run from the shell. The return status is 0.
.TP
-\fBtrap\fP [\fB\-lp\fP] [\fIarg\fP] [\fIsigspec\fP ...]
+\fBtrap\fP [\fB\-lp\fP] [[\fIarg\fP] \fIsigspec\fP ...]
The command
.I arg
is to be read and executed when the shell receives
.IR sigspec .
If
.I arg
-is absent or
+is absent (and there is a single \fIsigspec\fP) or
.BR \- ,
-all specified signals are
-reset to their original values (the values they had
+each specified signal is
+reset to its original disposition (the value it had
upon entrance to the shell).
If
.I arg
.B \-p
is given,
.B trap
-prints the list of commands associated with each signal number.
+prints the list of commands associated with each signal.
+The
+.B \-l
+option causes the shell to print a list of signal names and
+their corresponding numbers.
Each
.I sigspec
is either
a signal name defined in <\fIsignal.h\fP>, or a signal number.
+Signal names are case insensitive and the SIG prefix is optional.
If a
.I sigspec
is
.B EXIT
(0) the command
.I arg
-is executed on exit from the shell. If a
+is executed on exit from the shell.
+If a
.I sigspec
is
.SM
.BR DEBUG ,
the command
.I arg
-is executed after every \fIsimple command\fP (see
+is executed before every \fIsimple command\fP, \fIfor\fP command,
+\fIcase\fP command, \fIselect\fP command, every arithmetic \fIfor\fP
+command, and before the first command executes in a shell function (see
.SM
.B SHELL GRAMMAR
above).
+Refer to the description of the \fBextdebug\fP option to the
+\fBshopt\fP builtin for details of its effect on the \fBDEBUG\fP trap.
+If a
+.I sigspec
+is
+.SM
+.BR ERR ,
+the command
+.I arg
+is executed whenever a simple command has a non\-zero exit status,
+subject to the following conditions.
The
-.B \-l
-option causes the shell to print a list of signal names and
-their corresponding numbers.
+.SM
+.B ERR
+trap is not executed if the failed
+command is part of the command list immediately following a
+.B while
+or
+.B until
+keyword,
+part of the test in an
+.I if
+statement, part of a
+.B &&
+or
+.B \(bv\(bv
+list, or if the command's return value is
+being inverted via
+.BR ! .
+These are the same conditions obeyed by the \fBerrexit\fP option.
+If a
+.I sigspec
+is
+.SM
+.BR RETURN ,
+the command
+.I arg
+is executed each time a shell function or a script executed with the
+\fB.\fP or \fBsource\fP builtins finishes executing.
Signals ignored upon entry to the shell cannot be trapped or reset.
-Trapped signals are reset to their original values in a child
-process when it is created.
+Trapped signals that are not being ignored are reset to their original
+values in a child process when it is created.
The return status is false if any
.I sigspec
is invalid; otherwise
.B trap
returns true.
.TP
-\fBtype\fP [\fB\-atp\fP] \fIname\fP [\fIname\fP ...]
+\fBtype\fP [\fB\-aftpP\fP] \fIname\fP [\fIname\fP ...]
With no options,
indicate how each
.I name
that would be executed if
.I name
were specified as a command name,
-or nothing if \f(CWtype -t name\fP
+or nothing if
+.if t \f(CWtype -t name\fP
+.if n ``type -t name''
+would not return
+.IR file .
+The
+.B \-P
+option forces a
+.SM
+.B PATH
+search for each \fIname\fP, even if
+.if t \f(CWtype -t name\fP
+.if n ``type -t name''
would not return
.IR file .
If a command is hashed,
.B \-p
-prints the hashed value, not necessarily the file that appears
+and
+.B \-P
+print the hashed value, not necessarily the file that appears
first in
.SM
.BR PATH .
The table of hashed commands is not consulted
when using
.BR \-a .
+The
+.B \-f
+option suppresses shell function lookup, as with the \fBcommand\fP builtin.
.B type
returns true if any of the arguments are found, false if
none are found.
.TP
-\fBulimit\fP [\fB\-SHacdflmnpstuv\fP [\fIlimit\fP]]
+\fBulimit\fP [\fB\-SHacdefilmnpqrstuvx\fP [\fIlimit\fP]]
Provides control over the resources available to the shell and to
-processes started by it, on systems that allow such control. The
-value of
-.I limit
-can be a number in the unit specified for the resource, or the
-value
-.BR unlimited .
+processes started by it, on systems that allow such control.
The \fB\-H\fP and \fB\-S\fP options specify that the hard or soft limit is
set for the given resource. A hard limit cannot be increased once it
is set; a soft limit may be increased up to the value of the hard limit.
If neither \fB\-H\fP nor \fB\-S\fP is specified, both the soft and hard
limits are set.
+The value of
+.I limit
+can be a number in the unit specified for the resource
+or one of the special values
+.BR hard ,
+.BR soft ,
+or
+.BR unlimited ,
+which stand for the current hard limit, the current soft limit, and
+no limit, respectively.
If
.I limit
is omitted, the current value of the soft limit of the resource is
.B \-d
The maximum size of a process's data segment
.TP
+.B \-e
+The maximum scheduling priority ("nice")
+.TP
.B \-f
-The maximum size of files created by the shell
+The maximum size of files written by the shell and its children
+.TP
+.B \-i
+The maximum number of pending signals
.TP
.B \-l
The maximum size that may be locked into memory
.B \-p
The pipe size in 512-byte blocks (this may not be set)
.TP
+.B \-q
+The maximum number of bytes in POSIX message queues
+.TP
+.B \-r
+The maximum real-time scheduling priority
+.TP
.B \-s
The maximum stack size
.TP
.TP
.B \-v
The maximum amount of virtual memory available to the shell
+.TP
+.B \-x
+The maximum number of file locks
.PD
.PP
If
.B \-n
and
.BR \-u ,
-which are unscaled values. The return status is 0
-unless an invalid option is encountered, a non-numeric argument
-other than \fBunlimited\fP is supplied as \fIlimit\fP, or an
-error occurs while setting a new limit.
+which are unscaled values.
+The return status is 0 unless an invalid option or argument is supplied,
+or an error occurs while setting a new limit.
.RE
.TP
\fBumask\fP [\fB\-p\fP] [\fB\-S\fP] [\fImode\fP]
Read-only variables may not be unset.
If
.B \-f
-is specifed,
-each
+is specified, each
.I name
refers to a shell function, and the function definition
is removed.
are unset, they lose their special properties, even if they are
subsequently reset. The exit status is true unless a
.I name
-does not exist or is readonly.
+is readonly.
.TP
-\fBwait\fP [\fIn\fP]
-Wait for the specified process and return its termination
-status.
+\fBwait\fP [\fIn ...\fP]
+Wait for each specified process and return its termination status.
+Each
.I n
may be a process
ID or a job specification; if a job spec is given, all processes
.B enable
builtin command
.IP \(bu
+Using the \fBenable\fP builtin command to enable disabled shell builtins
+.IP \(bu
specifying the
.B \-p
option to the
.PP
These restrictions are enforced after any startup files are read.
.PP
-When a command that is found to be a shell script is executed (see
+.ie \n(zY=1 When a command that is found to be a shell script is executed,
+.el \{ When a command that is found to be a shell script is executed
+(see
.SM
.B "COMMAND EXECUTION"
above),
+\}
.B rbash
turns off any restrictions in the shell spawned to execute the
script.
.PP
Chet Ramey, Case Western Reserve University
.br
-chet@ins.CWRU.Edu
+chet@po.cwru.edu
.SH BUG REPORTS
If you find a bug in
.B bash,
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
-.B bash
-that you have.
+.BR bash .
+The latest version is always available from
+\fIftp://ftp.gnu.org/pub/bash/\fP.
.PP
Once you have determined that a bug actually exists, use the
.I bashbug
.PP
Comments and bug reports concerning
this manual page should be directed to
-.IR chet@ins.CWRU.Edu .
+.IR chet@po.cwru.edu .
.SH BUGS
.PP
It's too big and too slow.
.PP
Commands inside of \fB$(\fP...\fB)\fP command substitution are not
parsed until substitution is attempted. This will delay error
-reporting until some time after the command is entered.
+reporting until some time after the command is entered. For example,
+unmatched parentheses, even inside shell comments, will result in
+error messages while the construct is being read.
.PP
Array variables may not (yet) be exported.
.zZ
projects / platform / upstream / bash.git / blobdiff