title: Perl regex with exclamation marks
body: <p>How do you define/explain this Perl regex:</p>
  
  <pre><code>$para =~ s!//!/!g;
  </code></pre>
  
  <p>I know the <code>s</code> means search, and <code>g</code> means global (search), but not sure how the exclamation marks <code>!</code> and extra slashes <code>/</code> fit in (as I thought the pattern would look more like <code>s/abc/def/g</code>).</p>