#!/bin/sh
depth="-maxdepth 1"
case "$1" in
  -r|--recursive) depth="" ;;
  -h|--help)
    echo "Usage: $(basename "$0") [-r]"
    echo "  -r, --recursive   search subdirectories too"
    exit 0
    ;;
esac

find . $depth -type f -exec md5sum {} + | sort | awk '{
  if ($1 == prev) print "rm " $2
  prev = $1
}'