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

This is actually pretty easy. Just drop the trailing colon after the R and use OPTIND

while getopts "hRd:" opt; do
   case $opt in
      h) echo -e $USAGE && exit
      ;;
      d) DIR="$OPTARG"
      ;;
      R)       
        if [[ ${@:$OPTIND} =~ ^[0-9]+$ ]];then
          LEVEL=${@:$OPTIND}
          OPTIND=$((OPTIND+1))
        else
          LEVEL=1
        fi
      ;;
      \?) echo "Invalid option -$OPTARG" >&2
      ;;
   esac
done
echo $LEVEL $DIR

count.sh -d test

test

count.sh -d test -R

1 test

count.sh -R -d test

1 test

count.sh -d test -R 2

2 test

count.sh -R 2 -d test

2 test