title: exec function does not work out
body: <pre><code>&lt;?php
      exec("whoami");
  
  ?&gt;
  </code></pre>
  
  <p>I can be more explicit with the code . Although When I'm trying to call the php file with my browser nothing happens (of course I'm using apache and the whole).</p>
  
  <p>Note : The safe_mode is activated, I'm using php5, php interpreter seems to be nice when running other functions, I'm a ubuntu user.</p>
  
  <p>Then what is wrong?</p>