title: How to Add a filter to single.php only in wordpress?
body: <p>I want to add nofollow rel to tag cloud on single post only. This function code in functions.php works fine but I couldn't figure it out how to restrict it to single.php only.</p>
  
  <pre><code>function szub_nofollow_tag($text) {
  return str_replace('&lt;a href=', '&lt;a rel="nofollow" href=',  $text);
  }
  
  
  add_filter('wp_tag_cloud', 'szub_nofollow_tag');    
  </code></pre>
  
  <p>Could you please tell me how to do it??</p>