I had one gigantic directory of all my tagged and organized mp3 files. Problem is it was too big to use. This bloated my library and I have since not been able to fit my music on my laptop. I needed to manipulate mp3 files by genre and extract them out of this single directory to create smaller libraries. I spent all of about two minutes looking for a program to do this before deciding to write a script. Truthfully, it was worse: once upon a time I over-enthusiastically downloaded StepMania and 493 DDR games/songs. And then, I added all the songs into my music library. It’s a great party game, but not the kind of music I want to listen to.

Many implementations exist for reading ID3 tags. I first tried ruby-mp3info, however it didn’t read my custom genre (‘DDR’) so then I moved to id3lib-ruby which uses the c++ id3lib library.

This worked like a charm. I ran the script over all my directories and built up a list of the directories.

#!/usr/bin/env ruby
# find_music.sh
require "rubygems"
require 'id3lib'
require 'find'
require 'set'
 
ddr_files = []
ddr_dirs = Set.new
 
search_dir = '~/media/music/music_categorized'
 
Find.find(search_dir) do |file|
  next if file !~ /.*mp3$/
  mp3 = ID3Lib::Tag.new(file)
  next if mp3.genre != 'DDR'
  ddr_dirs << File.dirname(file)
  ddr_files << file   puts "%s, %s --> AT: %s" % [mp3.genre, mp3.album, file]
end
 
File.open('result-ddr-files.txt', 'w') do |f|
  f.write(ddr_files.join("\n"))
end
 
File.open('result-ddr-dirs.txt', 'w') do |f|
  ddr_dirs.each { |d| f.write("%s\n" % d)}
end

Next I reviewed the two output files, then ran the file result-ddr-dirs.txt in as an argument into this next script. That removed almost a gig of music from my library.

#!/usr/bin/env ruby
 
if (ARGV.length != 1)
  puts "Usage: #{__FILE__} input_file"
  exit(1)
end
 
destination="/home/jwolter/media/music/music_ddr_questionable_value/"
 
File.foreach(ARGV[0]) do |line|
  next if line.strip == ""
  cmd =  "mv \"#{line.strip}\" \"#{destination}\""
  #puts cmd
  `#{cmd}`
end

Bonus: In the process searching for this, I ran into the ID3 Tags RubyQuiz.

One of the nicest benefits of being a software engineer is I avoid doing boring manual tasks on my computer. Writing a script is more fun, and faster. I’ve got many scripts to automate file manipulation, online banking, and more. What bit of your automation scripts do you think is the most helpful?