http://linuxcommand.org/lc3_wss0120.php

parse_arg.sh

#!/bin/bash

interactive=
filename=~/sysinfo_page.html

while [ "$1" != "" ]; do
    case $1 in
        -f | --file )           shift
                                filename="$1"
                                ;;
        -i | --interactive )    interactive=1
                                ;;
        -h | --help )           usage
                                exit
                                ;;
        * )                     usage
                                exit 1
    esac
    shift
done