Parses script/function options. Simple parsing, just for reference

options_parse_simple

#!/bin/bash
local _optstring=':f:'
while getopts "${_optstring}" _opt; do
	case "${_opt}" in
        	f)
        		_f="${OPTARG}"
        	;;
        	*)
        		return 255
        	;;
	esac
done
shift $((${OPTIND}-1))