my_shellscript_templete.sh

#!/bin/bash

function usage () {
cat << EOS

Usage:
    $(basename ${0}) [OPTIONS]... MUST_ARG

Options:
    --help, -h        print this
    --option, -o      optional arg

EOS
}

OPT=`getopt -o ho: -l help,option: -- "$@"`
if [ $? != 0 ] ; then
  usage
  exit 1
fi
eval set -- "$OPT"

MUST_ARG=""
OPT_ARG=""

while true
do
  case $1 in
    -o | --option)
        OPT_ARG=$2
        shift 2
        ;;
    --)
        MUST_ARG=$2
        shift
        break
        ;;
    *)
        usage
        exit 1
        ;;
  esac
done

if [ -z $MUST_ARG ]; then
  echo "Must have MUST_ARG"
  usage
  exit 1
fi

if [ -z $OPT_ARG ]; then
  OUT_ARG=default_val
  echo "OUT_ARG is default($OUTDIR)"
fi

echo $MUST_ARG
echo $OUT_ARG