# File lib/webby/filters/tidy.rb, line 48
  def process
    cmd = "tidy %s -q -f #{@err.path}" % ::Webby.site.tidy_options
    out = IO.popen(cmd, 'r+') do |tidy|
      tidy.write @str
      tidy.close_write
      tidy.read
    end

    if File.size(@err.path) != 0
      @log.warn File.read(@err.path).strip
    end

    return out
  end