NT Syntax
LOGOFF.exe (Resource Kit)

Log a user off.

      LOGOFF [/f] [/n] 

   /f   Force running processes to close, but will ask for user confirmation.
         The user will not be asked to save unsaved data. 

   /n   Force running processes to close without confirmation. 
        The user will be prompted to save unsaved data. 

By default LOGOFF will ask for user confirmation and prompt to save unsaved data.

Windows XP includes the SHUTDOWN command that can now logoff a user.

"The man who is tired of London is tired of looking for a parking space" - Paul Theroux

Related Commands:

shutgui.exe - is a GUI version of SHUTDOWN.exe
SHUTDOWN - Shutdown the computer

Equivalent Linux BASH commands:

Simon Sheppard