Play random files with Ruby

I’ve written a class to play random files, you can define the player path and allowed file extentions. It will search recursively for all readable files, starting from execution from the folder passed as argument or, if miss, from current folder. Tested on a linux box with mplayer.

Usage:
$ ./shuffle # play recursively all files from current folder $ ./shuffle /path/to/files # play recursively all files from specified folder

That’s the source code.
#!/usr/bin/ruby


player = "/usr/local/bin/mplayer"
formats = ["mp3", "ogg", "flv"]
folder = ARGV[0] || ""

class ShufflePlayer
  @files
  @frx
  @player
  def initialize(player, formats, folder)
    @player = player
    gen_regex(formats)
    load_files(folder)
  end

  def play
    flag = 1
    while flag &amp;&amp; @files.length &gt; 0
      flag = system("#{@player} -quiet #{@files.delete(@files[rand(Time.now) % @files.length])}")
    end
  end

  private
  def load_files(folder)
    @files = Dir[folder+'**/*.*'].reject!{|f| f if @frx.match(f).nil? || !File.readable?(f) }
    @files.collect!{|f| f.gsub(/['"\-\s\[\]\(\)]/){ |m| "\\"+m }} unless @files.nil?
  end

  def gen_regex(formats)
    @frx = /(#{formats.join('|')})$/
  end
end

ShufflePlayer.new(player,formats,folder).play

Security disclaimer: this code is strong insecure, i’ve posted for study purpouses, I’m not responsable if someone use it to attack your system.