title: Check if a line does not start with a specific string with grep
body: <p>I have a file app.log</p>
  
  <pre><code>Oct 06 03:51:43 test test
  Nov 06 15:04:53 text text text 
  more text more text
  Nov 06 15:06:43 text text text
  Nov 06 15:07:33
  more text more text
  Nov 06 15:14:23  test test
  more text more text
  some more text 
  Nothing but text
  some extra text
  Nov 06 15:34:31 test test test
  </code></pre>
  
  <p>How do I grep all the lines that does not begin with Nov 06 ?</p>
  
  <p>I have tried </p>
  
  <pre><code>grep -En "^[^Nov 06]" app.log
  </code></pre>
  
  <p>I am not able to get lines which have 06 in them.</p>