title: How to filter files in directory in linux
body: <p>How to display the types of all the files in the personal directory in home directory<br>
  that:</p>
  
  <ol>
  <li>do not start with certain letters like <code>a</code>, <code>k</code></li>
  <li>and the third letter in their name is not a digit and not a letter 
  (upper or lower case)</li>
  </ol>