mp_set_title.rb

#!/usr/bin/env ruby

require 'taglib'

MP_FILE_CLASSES = {'.mp3' => TagLib::MPEG::File, '.m4a' => TagLib::MP4::File}

def set_mp_audio_file_to_title(path, title)
  MP_FILE_CLASSES[File.extname(path)].open(path) {|mp| mp.tag.title = title; mp.save}
  puts "  set #{path} title=#{title}"
rescue
  puts "  error: #{$!}"
  exit(-1)
end

if ARGV.count < 2
  puts "Usage: #{$0} MPEG_AUDIO_FILE TITLE  or"
  puts "       #{$0} -f FILE_AND_TITLE_LIST"
elsif ARGV[0] == '-f'
  IO.readlines(ARGV[1]).each do |line| 
    path_title = line.split("\t")
    set_mp_audio_file_to_title(*path_title) if path_title.length == 2
  end
else
  set_mp_audio_file_to_title(ARGV[0], ARGV[1])
end

exit(0)