getopt works quite marvelously, and re-inventing the wheel is pretty retarded.

Six levels of nesting, just to parse parameters looks like a maintainability nightmare, compared to a single, simple while/case loop.

http://codesnippets.joyent.com/posts/show/1697

help getopt;

It’s a bash built-in (and mostly compatible binaries that the built-in was based off of exist on any sane system even without bash!).

Example usage:

# Parse commandline options.
GETOPT=”$(getopt -o c:olhdfs –long children:,stdout,syslog,help,dry-run,force,status -n “$0″ — “$@”)”
if [ "$?" -gt '0' ]; then
echo “$USAGE”
exit 1
fi

eval set — “$GETOPT”

while true; do
case “$1″ in
-h|–help) echo “$USAGE”; exit 0 ;;
-c|–children) if [ "$2" -gt '0' ] >/dev/null 2>&1; then
MAXCHILDREN=”$2″;
shift;
shift;
else
echo “Number of children MUST be an integer.”;
exit 1;
fi
;;
-o|–stdout) TTYOUT=1; shift ;;
-l|–syslog) SYSLOGOUT=1; shift ;;
-d|–dry-run) TTYOUT=1; DRYRUN=1; shift ;;
-s|–status) TTYOUT=1; STATUSONLY=1; shift ;;
-f|–force) FORCE=1; shift ;;
–) shift; break ;;
*) echo “Invalid Option ${1}.”; echo “$USAGE”; exit 1 ;;
esac
done

Watching closer on the script I discovered, that the script already support that style of arguments.

However, it doesn’t support other things. Imagine

mv -i oldname newname

This would lead to i=oldname and newname -> ???

In short: This script helps in parsing command line options, but it isn’t the non-plus-ultra yet.

Regards, Bodo

@Milian Wolff:

It doesn’t make a difference if you write

run.sh –file “foobar” –arguments “–foo”

or if you write

run.sh –file “foobar” –arguments –foo

For this reason the script should be updates to allow for arguments like “–arguments=–foo”

Regards, Bodo

1. Instead of

OIFS=$IFS; IFS=$(echo -e “\n”); getopt $@; IFS=$OIFS

you could also just write

getopt “$@”

2. It may be a security problem if the getopt function may write any variable in the normal namespace of the script. So, it’s better to prefix each variable by e.g. “arg_”. So –name bothie won’t get name=”bothie” but arg_name=”bothie”.

Regards, Bodo

Thanks for sharing!

-Jeremy