Optional option argument with getopts

Question

while getopts \"hd:R:\" arg; do
  case $arg in
    h)
      echo \"usgae\" 
      ;;
    d)
      dir=$OPTARG
      ;;
    R)
      if [[ $OPTARG =~ ^[0-9]+$ ]];then         


        

Answer 1

I think there are two way.

First is calandoa's answer, Using OPTIND and no silent mode.

Second is Using OPTIND and silent mode.

while getopts ":Rr:" name; do
    case ${name} in
        R)
            eval nextArg=\${$OPTIND}
            # check option followed by nothing or other option.
            if [[ -z ${nextArg} || $nextArg =~ ^-.* ]]; then
                level=1
            elif [[ $nextArg =~ ^[0-9]+$ ]]; then
                level=$nextArg
                OPTIND=$((OPTIND + 1))
            else
                level=1
            fi
            ;;
        r)
            # check option followed by other option.
            if [[ $OPTARG =~ ^-.* ]]; then
                OPTIND=$((OPTIND - 1))
                level2=2
            elif [[ $OPTARG =~ ^[0-9]+$ ]]; then
                level2="$OPTARG"
            else
                level2=2
            fi
            ;;
        :)
            # check no argument
            case $OPTARG in
                r)
                    level2=2
                    ;;
            esac
    esac
done

echo "Level 1 : $level"
echo "Level 2 : $level2"