GETOPT
Section: User Commands (1)
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BSD mandoc
NAME
getopt
- parse command options
SYNOPSIS
args=`getopt optstring $*`
set -- `getopt optstring $*`
DESCRIPTION
is used to break up options in command lines for easy parsing by
shell procedures, and to check for legal options.
[Optstring]
is a string of recognized option letters (see
getopt(3)
);
if a letter is followed by a colon, the option
is expected to have an argument which may or may not be
separated from it by white space.
The special option
``--''
is used to delimit the end of the options.
will place
``--''
in the arguments at the end of the options,
or recognize it if used explicitly.
The shell arguments
($1 $2 ...) are reset so that each option is
preceded by a
``-''
and in its own shell argument;
each option argument is also in its own shell argument.
EXAMPLE
The following code fragment shows how one might process the arguments
for a command that can take the options
[a]
and
[b]
and the option
[o]
which requires an argument.
args=`getopt abo: $*`
if test $? != 0
then
echo 'Usage: ...'
exit 2
fi
set -- $args
for i
do
case "$i"
in
-a|-b)
flag=$i; shift;;
-o)
oarg=$2; shift; shift;;
--)
shift; break;;
esac
done
This code will accept any of the following as equivalent:
cmd -aoarg file file
cmd -a -o arg file file
cmd -oarg -a file file
cmd -a -oarg -- file file
St -p1003.2
mandates that the
sh(1)
set command return the value of 0 for the exit status. Therefore,
the exit status of the
command is lost when
and the
sh(1)
set command are used on the same line. The example given
is one way to detect errors found by
SEE ALSO
sh(1),
getopt(3)
DIAGNOSTICS
prints an error message on the standard error output when it
encounters an option letter not included in
[optstring]
HISTORY
Written by Henry Spencer, working from a Bell Labs manual page.
Behavior believed identical to the Bell version.
BUGS
Whatever
getopt(3)
has.
Arguments containing white space or embedded shell metacharacters
generally will not survive intact; this looks easy to fix but isn't.
The error message for an invalid option is identified as coming
from
rather than from the shell procedure containing the invocation
of
this again is hard to fix.
The precise best way to use the
set
command to set the arguments without disrupting the value(s) of
shell options varies from one shell version to another.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- EXAMPLE
-
- SEE ALSO
-
- DIAGNOSTICS
-
- HISTORY
-
- BUGS
-
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Time: 04:29:47 GMT, April 24, 2025