function hexdiff {
  if [ "$#" -ne 3 ]; then
      echo "Usage: hexdiff size file1 file2" >&2
      return 1
  fi
  local size=$1
  local file1=$2
  local file2=$3
  if [ ! -e "$file1" ]; then
      echo "File '$file1' not found"
      return 1
  fi
  if [ ! -e "$file2" ]; then
      echo "File '$file2' not found"
      return 1
  fi
  echo $size
  diff <(tail -c $size $file1 | od -t x1 -A x) <(tail -c $size $file2 | od -t x1 -A x)
}