title: What does =~ do in Perl?
body: <p>I guess the tag is a variable, and it is checking for <code>9eaf</code> - but does this exist in Perl?</p>
  
  <p>What is the "=~" sign doing here and what are the "/" characters before and after <code>9eaf</code> doing?</p>
  
  <pre><code>if ($tag =~ /9eaf/)
  {
      # Do something
  }
  </code></pre>