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Chet Ramey
2011-12-07 09:25:28 -05:00
parent fdf670eaa1
commit 09767ff09d
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@@ -5,12 +5,12 @@
.\" Case Western Reserve University
.\" chet@po.cwru.edu
.\"
.\" Last Change: Sun Jun 29 22:44:15 EDT 2008
.\" Last Change: Sun Jul 6 14:33:52 EDT 2008
.\"
.\" bash_builtins, strip all but Built-Ins section
.if \n(zZ=1 .ig zZ
.if \n(zY=1 .ig zY
.TH BASH 1 "2008 June 29" "GNU Bash-4.0"
.TH BASH 1 "2008 July 6" "GNU Bash-4.0"
.\"
.\" There's some problem with having a `@'
.\" in a tagged paragraph with the BSD man macros.
@@ -871,6 +871,42 @@ The exit status of the \fBwhile\fP and \fBuntil\fP commands
is the exit status
of the last \fBdo\fP \fIlist\fP command executed, or zero if
none was executed.
.SS Coprocesses
.PP
A \fIcoprocess\fP is a shell command preceded by the \fBcoproc\fP reserved
word.
A coprocess is executed asynchronously in a subshell, as if the command
had been terminated with the \fB&\fP control operator, with a two-way pipe
established between the executing shell and the coprocess.
.PP
The format for a coprocess is:
.RS
.PP
\fBcoproc\fP [\fINAME\fP] \fIcommand\fP [\fIredirections\fP]
.RE
.PP
This creates a coprocess named \fINAME\fP.
If \fINAME\fP is not supplied, the default name is \fICOPROC\fP.
When the coproc is executed, the shell creates an array variable (see
.B Arrays
below) named \fINAME\fP in the context of the executing shell.
The standard output of
.I command
is connected via a pipe to a file descriptor in the executing shell,
and that file descriptor is assigned to \fINAME\fP[0].
The standard input of
.I command
is connected via a pipe to a file descriptor in the executing shell,
and that file descriptor is assigned to \fINAME\fP[1].
This pipe is established before any redirections specified by the
command (see
.SM
.B REDIRECTION
below).
The file descriptors can be utilized as arguments to shell commands
and redirections using standard word expansions.
.PP
The return status of a coprocess is the exit status of \fIcommand\fP.
.SS Shell Function Definitions
.PP
A shell function is an object that is called like a simple command and
@@ -2116,15 +2152,15 @@ parser to treat the rest of the line as a comment.
.SS Arrays
.B Bash
provides one-dimensional indexed and associative array variables.
Any variable may be used as an array; the
Any variable may be used as an indexed array; the
.B declare
builtin will explicitly declare an array.
There is no maximum
limit on the size of an array, nor any requirement that members
be indexed or assigned contiguously.
Indexed arrays are referenced using integers (including arithmetic
expressions) and are zero-based; associative arrays use arbitrary
strings.
expressions) and are zero-based; associative arrays are referenced
using arbitrary strings.
.PP
An indexed array is created automatically if any variable is assigned to
using the syntax \fIname\fP[\fIsubscript\fP]=\fIvalue\fP. The
@@ -2138,21 +2174,24 @@ use
.B SHELL BUILTIN COMMANDS
below).
.B declare \-a \fIname\fP[\fIsubscript\fP]
is also accepted; the \fIsubscript\fP is ignored. Attributes may be
is also accepted; the \fIsubscript\fP is ignored.
.PP
Associative arrays are created using
.BR "declare \-A \fIname\fP" .
.PP
Attributes may be
specified for an array variable using the
.B declare
and
.B readonly
builtins. Each attribute applies to all members of an array.
.PP
Associative arrays are created using
.BR declare \-A \fIname\fP .
.PP
Arrays are assigned to using compound assignments of the form
\fIname\fP=\fB(\fPvalue\fI1\fP ... value\fIn\fP\fB)\fP, where each
\fIvalue\fP is of the form [\fIsubscript\fP]=\fIstring\fP. Only
\fIstring\fP is required. When using indexed arrays, if
the optional brackets and subscript are supplied, that index is assigned to;
\fIvalue\fP is of the form [\fIsubscript\fP]=\fIstring\fP.
Indexed array assignments do not require the bracket and subscript.
When assigning to indexed arrays, if the optional brackets and subscript
are supplied, that index is assigned to;
otherwise the index of the element assigned is the last index assigned
to by the statement plus one. Indexing starts at zero.
.PP
@@ -2508,11 +2547,13 @@ If \fIoffset\fP evaluates to a number less than zero, the value
is used as an offset from the end of the value of \fIparameter\fP.
If \fIparameter\fP is \fB@\fP, the result is \fIlength\fP positional
parameters beginning at \fIoffset\fP.
If \fIparameter\fP is an array name indexed by @ or *,
If \fIparameter\fP is an indexed array name subscripted 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.
Substring expansion applied to an associative array produces undefined
results.
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
@@ -2653,6 +2694,43 @@ or
.BR * ,
the substitution operation is applied to each member of the
array in turn, and the expansion is the resultant list.
.TP
${\fIparameter\fP\fB^\fP\fIpattern\fP}
.PD 0
.TP
${\fIparameter\fP\fB^^\fP\fIpattern\fP}
.TP
${\fIparameter\fP\fB,\fP\fIpattern\fP}
.TP
${\fIparameter\fP\fB,,\fP\fIpattern\fP}
.PD
This expansion modifies the case of alphabetic characters in \fIparameter\fP.
The \fIpattern\fP is expanded to produce a pattern just as in
pathname expansion.
The \fB^\fP operator converts lowercase letters matching \fIpattern\fP
to uppercase; the \fB,\fP operator converts matching uppercase letters
to lowercase.
The \fB^^\fP and \fB,,\fP expansions convert each matched character in the
expanded value; the \fB^\fP and \fB,\fP expansions match and convert only
the first character.
If \fIpattern\fP is omitted, it is treated like a \fB?\fP, which matches
every character.
If
.I parameter
is
.B @
or
.BR * ,
the case modification operation is applied to each positional
parameter in turn, and the expansion is the resultant list.
If
.I parameter
is an array variable subscripted with
.B @
or
.BR * ,
the case modification operation is applied to each member of the
array in turn, and the expansion is the resultant list.
.SS Command Substitution
.PP
\fICommand substitution\fP allows the output of a command to replace
@@ -6645,10 +6723,10 @@ is greater than the number of enclosing loops, the last enclosing loop
(the ``top-level'' loop) is resumed.
The return value is 0 unless \fIn\fP is not greater than or equal to 1.
.TP
\fBdeclare\fP [\fB\-aAfFirtx\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] ...]
\fBdeclare\fP [\fB\-aAfFilrtux\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] ...]
.PD 0
.TP
\fBtypeset\fP [\fB\-aAfFirtx\fP] [\fB\-p\fP] [\fIname\fP[=\fIvalue\fP] ...]
\fBtypeset\fP [\fB\-aAfFilrtux\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.
@@ -6702,6 +6780,11 @@ The variable is treated as an integer; arithmetic evaluation (see
.B "ARITHMETIC EVALUATION" ") "
is performed when the variable is assigned a value.
.TP
.B \-l
When the variable is assigned a value, all upper-case characters are
converted to lower-case.
The upper-case attribute is disabled.
.TP
.B \-r
Make \fIname\fPs readonly. These names cannot then be assigned values
by subsequent assignment statements or unset.
@@ -6712,6 +6795,11 @@ 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 \-u
When the variable is assigned a value, all lower-case characters are
converted to upper-case.
The lower-case attribute is disabled.
.TP
.B \-x
Mark \fIname\fPs for export to subsequent commands via the environment.
.PD
@@ -7505,9 +7593,7 @@ is supplied, or
.B logout
Exit a login shell.
.TP
\fBmapfile\fP [\fB\-n\fP \fIcount\fP] [\fB\-O\fP \fIorigin\fP] [\fB\-s\fP \fIcou
nt\fP] [\fB\-t\fP] [\fB\-u\fP \fIfd\fP] [\fB\-C\fP \fIcallback\fP] [\fB\-c\fP \f
Iquantum\fP] [\fIarray\fP]
\fBmapfile\fP [\fB\-n\fP \fIcount\fP] [\fB\-O\fP \fIorigin\fP] [\fB\-s\fP \fIcount\fP] [\fB\-t\fP] [\fB\-u\fP \fIfd\fP] [\fB\-C\fP \fIcallback\fP] [\fB\-c\fP \fIquantum\fP] [\fIarray\fP]
Read lines from the standard input into array variable
.IR array ,
or from file descriptor
@@ -7709,7 +7795,7 @@ The return status is 0 unless an error occurs while
reading the name of the current directory or an
invalid option is supplied.
.TP
\fBread\fP [\fB\-ers\fP] [\fB\-a\fP \fIaname\fP] [\fB\-d\fP \fIdelim\fP] [\fb\-\fP \fItext\fP] [\fB\-n\fP \fInchars\fP] [\fB\-p\fP \fIprompt\fP] [\fB\-t\fP \fItimeout\fP] [\fB\-u\fP \fIfd\fP] [\fIname\fP ...]
\fBread\fP [\fB\-ers\fP] [\fB\-a\fP \fIaname\fP] [\fB\-d\fP \fIdelim\fP] [\fB\-\fP \fItext\fP] [\fB\-n\fP \fInchars\fP] [\fB\-p\fP \fIprompt\fP] [\fB\-t\fP \fItimeout\fP] [\fB\-u\fP \fIfd\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
@@ -7798,8 +7884,8 @@ are supplied, the line read is assigned to the variable
.SM
.BR REPLY .
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.
times out (in which case the return code is greater than 128), or an
invalid file descriptor is supplied as the argument to \fB\-u\fP.
.RE
.TP
\fBreadonly\fP [\fB\-aApf\fP] [\fIname\fP[=\fIword\fP] ...]
@@ -8555,11 +8641,10 @@ by default.
Suspend the execution of this shell until it receives a
.SM
.B SIGCONT
signal. The
signal. A login shell cannot be suspended; the
.B \-f
option says not to complain if this is
a login shell; just suspend anyway. The return status is 0 unless
the shell is a login shell and
option can be used to override this and force the suspension.
The return status is 0 unless the shell is a login shell and
.B \-f
is not supplied, or if job control is not enabled.
.TP
@@ -9249,5 +9334,7 @@ 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.
.PP
There may be only one active coprocess at a time.
.zZ
.zY