title: Delete FTP files with name containing a string (matching mask)
body: <p>I would like to delete all files on an FTP server, whose names contain a certain string.</p>
  
  <p>For example I have these files on the FTP:</p>
  
  <pre><code>pippo_1.jpg
  pippo_2.jpg
  pippo_3.jpg
  pluto_1.jpg
  </code></pre>
  
  <p>I would like delete all file that contain <code>pippo</code>.</p>
  
  <p>How can I delete all these files with a single operation?</p>
  
  <p>Thank you!</p>