wipe free space as command line option

can wipe free space be added as a command line option, this wound be useful in conjunction with the shutdown switch to do a free space wipe overnight as opposed to pare of a general clean

In the mean time you could right click the wfs option and click clean, have ccleaner minimize to tray, then right click the system tray icon and click "shut down after clean " or what ever it is called.

You know WFS only deletes already deleted files, doesn't free space, and doesn't improve performance at all, right ?