title: How do you diff a directory for only files of a specific type?
body: <p>I have a question about the diff command
  if I want a recursive directory diff but only for a specific file type, how to do that?</p>
  
  <p>I tried using the exclude option but can only use one pattern only:</p>
  
  <pre><code>$ diff /destination/dir/1 /destination/dir/2 -r -x *.xml
  </code></pre>
  
  <p>with the command I can only exclude xml file type, even though there are files in the folder image type (<code>png</code>, <code>gif</code>, <code>jpg</code>), <code>txt</code>, <code>php</code>, etc</p>
  
  <p>how to diff only certain file types.</p>