title: Find all file names that match a pattern
body: <p>I am trying to find a way to list all file names in a folder that matches this pattern :</p>
  
  <pre><code>20131106XXXXX.pdf 
  </code></pre>
  
  <p>The prefix is the date, and the content and length of <code>XXXX</code> vary across files, and I only care about pdf files. </p>
  
  <p>Anyone could advise a way to do this?</p>