Shell - Get command line arguments

getopt.sh

#!/bin/bash

args=$(getopt -o a:,b --long alpha:,beta -n "" -- "$@")
if [ $? != 0 ] ; then echo "Terminating..." >&2 ; exit 1 ; fi
eval set -- "${args}"

while true; do
    case "${1}" in
        -a | --alpha ) ALPHA="${2}"; shift 2 ;;
        -b | --beta ) BETA=gamma; shift 1 ;;
        * ) echo "${1}"; break ;;
    esac
done