optarg.md

shlib / core / optarg()

shlib.optarg

Given an option from the cmdline, extract the argument. The idea here is that when a command-line parser has identified a command-line option, this interface can extract the optional argument from the option, or from the argument following the option.

Example:

while test "$#" -gt '0'; do
	case "${1}" in
	(-a|-arg|--arg|--arg=*)
		OPTARG="$(shlib.optarg "${1}" "${2}")"
		test -z "${OPTARG}" || echo "argument=${OPTARG}";;
	esac
	shift
done

In the above example the argument may follow $1, or it may be embedded as part of $1, as in the case of --arg=Hello. The optarg() routine will parse $1 to extract the = condition. If no argument is found it will then evaluate $2 to see if it starts with a -, if it does not, then optarg returns $2, else it returns nothing.

See also: getarg