VLC - how to show FPS

If by FPS you mean the frame rate at which a video is played, you can access that information while playing by clicking on Tools >>> Codec information. In the video stream there should be a row with that information. (I'm basing myself on a Windows 2.0.2 version but it should also be valid for any other GUI).

If on the other hand you're looking for a overlaid FPS display I believe VLC doesn't do that, as mentioned before, but there should be some third party solutions.

that isn't available. (fps) All other info is available in debug messages if you run vlc with the -vvv option.