title: PHP preg_match url
body: <p>I have a problem with preg_match in PHP.</p>
  
  <p>I have URLs:</p>
  
  <pre><code>http://mysite.com/file/w867/2612512232
  http://mysite.com/file/c3233/2123255464
  etc.
  </code></pre>
  
  <p>I need URLs:</p>
  
  <pre><code>http://mysite.com/file/2612512232
  http://mysite.com/file/2123255464
  </code></pre>
  
  <p>I must remove:</p>
  
  <pre><code>w867/
  c3233/
  etc.
  </code></pre>