exec('top') doesn't return anything?
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/6653567/why-doesnt-exectop-work-on-linux">Why doesn&#39;t exec(&ldquo;top&rdquo;); work on Linux?</a>  </p>
</blockquote>



<p>exec('top') command doesn't return anything? How to fix this?</p>

<pre><code>$out = exec('whoami');

echo $out; //apache

$out = exec('top');
echo $out; //doesn't work why?
</code></pre>
