NAME

getopt − parse command options

SYNOPSIS

set −− `getopt optstring $∗`

DESCRIPTION

Getopt 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(3C)); 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.  Getopt 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. 

DIAGNOSTICS

Getopt prints an error message on the standard error when it encounters an option letter not included in optstring.

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. 

set −− `getopt abo: $∗`
if [ $? != 0 ]
then
echo $USAGE
exit 2
fi
for i in $∗
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

SEE ALSO

sh(1), getopt(3C). 

May 16, 1980