arguments

#!/bin/sh
# This script is licensed under the unlicense, please view the LICENSE file or go to https://unlicense.org/ for more information 
# Basic POSIX shell script which showcases arguments
HELP="Usage: arguments [-hvabcd]

This is a posix shell script to help study and understand commandline arguments

-h			help command
-v			version info
-a \"string\"		first parameter argument (required to exit with 0)
-b			b argument
-c			c argument
-d \"string\"		second parameter argument"
VERSION="1.1"
# getopts syntax is simple, single letter arguments only, : = argument with a parameter
while getopts ":vha:bcd:" opt; do
	case "$opt" in
		"h") echo "$HELP" # help information from above
			 exit 1;;
		"v") echo "$VERSION" # version information from above
			 exit 1;;
		"a") parameterA="$OPTARG";; # required parameter
		"b") echo "argument b";;
		"c") echo "argument c";;
		"d") parameterD="$OPTARG";; # required parameter
		*)   echo "$HELP"
			 exit 1;;
	esac
done

[ -z "$parameterA" ] && exit 1
echo "arg a: $parameterA"
[ -z "$parameterD" ] || echo "arg d: $parameterD" && exit