class File

  # Clean out all the empty dirs
  def File.clean(file_name)

    if File.directory? file_name
      # clean all subdirs
      subdirs = Dir.entries(file_name).select { |p| File.directory?(File.join(file_name, p)) }
      subdirs.reject! { |p| %w{. ..}.include? p }
      subdirs.each { |sd| File.clean File.join(file_name, sd) }

      # if its empty then delete it
      contents = Dir.entries(file_name).reject { |p| %w{. ..}.include? p }
      Dir.delete file_name if contents.empty?
    end
    
  end

end