title: Delete lines that contain two strings
body: <p>I am trying to delete some lines in a text file using <code>sed</code>. I only want to delete lines that contains two strings. The command <code>\|</code> is equivalent to the boolean <code>OR</code>. What is the command for the boolean operator <code>AND</code>?</p>
  
  <p>I am looking for something like this:</p>
  
  <pre><code>sed '/strA'AND'strB/d' file.txt
  </code></pre>