Unix command sudo?

Hi all,
When launching my app, I need to display a sudo password entry dialog box with AuthorizationMBS in order to memorize it for the different uses provided by my application. How to do because, at launch, I am not trying to execute a particular command. I need to find a Unix command which requires “sudo” rights (otherwise I get a 60031 error) and which is “mute”, i.e. which has no particular effect on the system (for example , a display to >/dev/null for example). Anyone have an order idea?