protected function toMarkdown($content)
    {
        $tmpfname = tempnam(sys_get_temp_dir(), 'fillet'); // good
        file_put_contents($tmpfname, $content);
        $cmd = $this->config['pandoc']['bin'] . ' --no-wrap -f html -t markdown ' . $tmpfname;
        $content = shell_exec($cmd);
        unlink($tmpfname);
        return $content;
    }