title: PHP error with user agent
body: <pre><code> &lt;?php
     $os = $_SERVER['HTTP_USER_AGENT'];
     echo $os();
   ?&gt;
  </code></pre>
  
  <p>This code does not work at all, but <code>echo $_SERVER['HTTP_USER_AGENT'];</code> does work. </p>
  
  <p>EDIT: Please ignore this, I fixed it with <code>print_r()</code>;</p>