title: System shutdown without password in ubuntu 11.04
body: <p>I'm writing a QT application which has a shutdown button. I want to shutdown system with this button but when I use the shell command "shutdown -h now" the system asks for password.<br>
  I want to shutdown without password.</p>
  
  <p>My QT code is:</p>
  
  <pre><code>QObject *parent;
  myProcess = new QProcess(this);
  QString command= "sudo shutdown";
  QStringList arguments;
  arguments &lt;&lt; "-h " &lt;&lt; "now"  ;
  myProcess-&gt;start(command,arguments);
  </code></pre>