Rename mp3s based on tags

renamer.rb

#!/usr/bin/env ruby

# Thanks to: Ahmad Azizan
# http://blog.lab69.com/2012/02/renaming-mp3-files-with-ruby.html

# You need to require this..
require 'rubygems'
require 'mp3info'

# This variable will hold your first argument as directory
# that contains mp3 files
dir = ARGV[0]
dir = File.expand_path(dir)

# Scan for files with .mp3 extension
mp3_list =  Dir.glob("#{dir}/*.mp3")

# Initialize variable 'artist' and 'song'
artist = ''
song = ''

# Loop all the list of files inside the array
mp3_list.each do |mp3_file|
  Mp3Info.open(mp3_file) do |mp3|
    if mp3.tag.artist.nil?
      # If artist tag not found, set as 'Unknown'
      artist =  "Unknown"
    else
      # If found, assign to variable artist.
      # replace character '/' to '\' to avoid
      # problem in renaming the file.
      artist = mp3.tag.artist.gsub(/\//,"\\")
    end
  
    if mp3.tag.title.nil?
      # If title tag not found, set as 'Unknown'
      song =  "Unknown"
    else
      # If found, assign to variable song.
      # replace character '/' to '\' to avoid
      # problem in renaming the file.
      song =  mp3.tag.title.gsub(/\//,"\\")
    end
  
    # combine as a new path
    new_name = "#{dir}/#{artist} - #{song}#{File.extname(mp3_file)}"
  
    unless mp3_file == new_name
      # If looping filename != newly combined path,
      # rename the file
      puts new_name
      File.rename(mp3_file, new_name)
    end
  end
end