title: Hidden features of Windows batch files
body: <p>What are some of the lesser know, but important and useful features of Windows batch files?</p>
  
  <p>Guidelines:</p>
  
  <ul>
  <li>One feature per answer</li>
  <li>Give both a short <strong>description</strong> of the feature and an <strong>example</strong>, not just a link to documentation</li>
  <li>Limit answers to <strong>native funtionality</strong>, i.e., does not require additional software, like the <em>Windows Resource Kit</em></li>
  </ul>
  
  <p>Clarification: We refer here to scripts that are processed by cmd.exe, which is the default on WinNT variants.</p>
  
  <p>(See also: <a href="https://stackoverflow.com/questions/148968/windows-batch-files-bat-vs-cmd">Windows batch files: .bat vs .cmd?</a>)</p>