title: php preg_replace subpattern
body: <p>I would like to highlight the last slug in url like this:</p>
  
  <p><a href="http://www.domain.org/" rel="nofollow">http://www.domain.org/</a><strong>school</strong>.html</p>
  
  <p>Here's the pattern to capture the slug:</p>
  
  <pre><code>$pattern = "/\/([^/]+)\.html$/";
  </code></pre>
  
  <p>How do I run preg_replace on url to replace the slug with <code>&lt;b&gt;slug&lt;/b&gt;</code>?</p>