while getopts ab: arg
do
     case $arg in
	a)    echo "option is -a"
              ;;
        b)    echo "option is -b"
              echo "option value for option \"-b\" is: $OPTARG"
              ;;
        :)    printf "$0: You must supply an argument to bash %OPTARG." >&2
              ;;
       \?)    echo "Usage: get_0 [-ab {arg}] " >&2
              exit 1
              ;;
     esac
done

exit 0
