#!/bin/bash
unset VERBOSE
while getopts 'smv' c
do
  echo "Processing $c : OPTIND is $OPTIND"
  case $c in
    s) ACTION=sha1sum ;;
    m) ACTION=md5sum ;;
    v) VERBOSE=true ;;
  esac
done

echo "Out of the getopts loop. OPTIND is now $OPTIND"
shift $((OPTIND-1))
if [ $VERBOSE ]; then
  set -x
fi
$ACTION $@