#!/bin/bash

opt_b=0
opt_c=0
scriptName=`basename $0`
showUsage() { echo "Usage: $scriptName -a <3333|7777> [-b] [-c]" 1>&2; exit 1; }

while getopts ":a:bc" opt; do
    case "${opt}" in
        a)
            opt_a=${OPTARG}
            ((opt_a == 3333 || opt_a == 7777)) || showUsage
            ;;
        b)
            opt_b=1
            ;;
        c)
            opt_c="yes"
            ;;
        \?)
            echo "Invalid option: $OPTARG" 1>&2
            exit 1;
            ;;
        :)
            echo "Invalid option: -$OPTARG requires an argument" 1>&2
            exit 1;
            ;;
    esac
done
shift $((OPTIND-1))

# if [ -z "${opt_a}" ] || [ -z "${opt_b}" ]; then

if [ -z "${opt_a}" ]; then
    showUsage
fi

echo "Results:"
echo "a = ${opt_a}"
echo "b = ${opt_b}"
echo "c = ${opt_c}"