renamer.rb

#!/usr/bin/env ruby

require 'rubygems'
require 'mp3info'

series = { 1 => "I", 2 => "II", 3 => "III", 4 => "IV", 5 => "V"}

1.upto(5) do |i|
  Dir.glob("Nivel #{i}/*.mp3").each do |entry|
    dirname = File.expand_path(File.dirname(entry))
    filename = File.basename(entry)
    if lec_match = filename.match(/(\d{2})\.mp3$/)
      lec_no = lec_match[1]
      p "#{filename} ===> #{lec_no}"
      Mp3Info.open(File.join(dirname,filename)) do |mp3|
        mp3.tag.title = "Lektion #{lec_no}"
        mp3.tag.album = "Serie #{series[i]}"
        mp3.tag.artist = "Deustch Warum Nicht"
        mp3.tag.tracknum = lec_no.to_i
      end
      File.rename(File.join(dirname, filename), File.join(dirname, "Serie #{series[i]} - Lektion #{lec_no}.mp3"))
    else
      p "ERROR with #{dirname}/#{filename}"
    end
  end
end