[Shell] OptionParamをもらう＋OptionParamを判定して必要な値が設定されていなければHelpMessageを表示する

manner.sh

while getopts f:t:r:h opt; do
    case $opt in
    f) FROM_DATE="${OPTARG}" ;;
    t) TO_DATE="${OPTARG}" ;;
    h) HELP="true" ;;
    *) ERROR="true" ;;
    esac
done

function help()
{
    echo "Usage : `basename $0` -f {FROM_DATE} -t {TO_DATE} " 1>&2
    echo "      {FROM_DATE} : YYYYmmdd" 1>&2
    echo "      {TO_DATE} : YYYYmmdd" 1>&2
    echo "      ex) `basename $0` -f 20101001 -t 20102001" 1>&2
}

if [ "${HELP}" == "true" -o "${ERROR}" == "true" -o "${FROM_DATE}" == "" -o "${TO_DATE}" == "" ]; then
    help
    exit 1
fi

if [[ ! $FROM_DATE =~ '^([0-9]{8,8})$' ]] || [[ ! $TO_DATE =~ '^([0-9]{8,8})$' ]] ; then
    help
    exit 1
fi


# logic start
...