title: clearing a list of domains / remove subdomains
body: <p>I have a large list of domains which is mixed with subdomains.</p>
  
  <pre><code>google.de
  spiegel.de
  sub1.google.de
  zeit.de
  sub1.spiegel.de
  </code></pre>
  
  <p>Is there a tool or a workaround in an editor (e.g. Sublime or Notepad++) to get all before domain.tld deleted?</p>
  
  <p>Notepad++ helped me to get this list cleared from all the other content, which has been inside. But at this point a stopped.</p>