Mine

#!/bin/bash

if [ "$#" == "0" ]; then
 echo "$0 file1 file2 file3 ... fileN"
 exit 1
fi

while (( "$#" )); do
 if [ ${1##*.} == "mp3" ]; then
  id3v2 --list "$1"
 else
  metaflac --export-tags-to=- "$1"
 fi
 shift
done