magento ship order

$orderId = 2;
$order = Mage::getModel('sales/order')->load($orderId);

$shipment = $order->prepareShipment();
 $shipment->register();
 $order->setIsInProcess(true);
 $order->addStatusHistoryComment('ship by aditya.', false);
 $transactionSave = Mage::getModel('core/resource_transaction')->addObject($shipment)      
  ->addObject($shipment->getOrder())
   ->save();