Ubuntu – How to find (and delete) duplicate files

Here's a bash script that renames the files passed to it based on their guessed format. It calls file to figure out the format by looking at characteristic patterns in the first few bytes. file -i prints lines like /path/to/file: type/subtype where type/subtype is a MIME type. The script then associates extensions to known types and renames the file to have the extension. Files that already have the extension are left alone. Files that have an unrecognized type are left alone. The script will prompt before overwriting a target file.

#!/bin/bash
# usage:
# fixmime ./{**/,}*
file --mime-type "$@" |
while read -r line; do
  file=${line%:*}
  type=${line##* }
  case $type in

    #Audio
    audio/x-flac) ext=flac;;
    audio/mpeg) ext=mp3;;
    application/ogg) ext=ogg;;

    #Video
    video/mp4) ext=mp4;;
    video/x-flv) ext=flv;;
    application/octet-stream) ext=webm;;
    application/x-shockwave-flash) ext=swf;;

    #Images
    image/png) ext=png;;
    image/jpeg) ext=jpg;;
    image/gif) ext=gif;;
    image/x-ico) ext=ico;;

    #Text
    text/plain) ext=md;; #markup your notes, even when they are plain
    text/html) ext=html;;
    text/x-pascal) ext=py;;
    text/x-c++) ext=js;; #conflicts with .cpp, so use prefered
    text/x-c) ext=scss;; #usualy it is .c
    text/x-shellscript) ext=sh;;
    application/pdf) ext=pdf;;

    #Fonts
    application/x-font-ttf) ext=ttf;;
    application/vnd.ms-opentype) ext=otf;;

    #Archive
    application/x-gzip) ext=tar.gz;;
    application/x-bzip2) ext=tar.bz;;

    *) continue;;
  esac
  [[ $file = *.$ext ]] || mv -i -- "$file" "$file.$ext"
done

Save the script as ~/bin/rename-based-on-content-type (or whatever you like) and make it executable (chmod +x ~/bin/rename-based-on-content-type). Pass the names of the files you want to rename to the script on the command line. If you have a directory tree /path/to/music/directory that you want to traverse recursively, invoke the script as

~/bin/rename-based-on-content-type /path/to/music/directory/{**/,}*

Puddletag should do everything you asked for. There's also an article on it at Ubuntu Geek

MusicBrainz Picard can automatically identify albums via audio finger-printing. If the music is not popular enough to be entered into their open database, you can add an entry and finger-prints for future users.