Lancer un script en tâche de fond en PHP

<?php
  $cmd = 'php toto.php';
 
  if(isset($_SERVER['PWD']) //unix
  {
    $nullResult = `$cmd > /dev/null &`;
  }
  else //windows
  {
    $WshShell = new COM("WScript.Shell");
    $oExec = $WshShell->Run($cmd, 7, false);
  }
?>