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

This document was created by man2html, using the manual pages.
Time: 04:29:47 GMT, April 24, 2025