source: trunk/essentials/app-shells/bash/tests/getopts6.sub

aflag=
bflag=

while getopts :ac name "$@"
do
        case $name in
        a)      aflag=1 ;;
        c)      cflag=1 ;;
        ?)      exit 2;;
        esac

        # this came in in a bug report -- it's really a usage error
        # but it shouldn't cause the shell to crash
        shift
done

if [ ! -z "$aflag" ] ; then echo -a specified ; fi
if [ ! -z "$cflag" ] ; then echo -c specified ; fi

if [ "$OPTIND" -gt 1 ]
then
        shift $(( $OPTIND - 1 ))
fi

echo remaining args: "$*"

exit 0