Log a user off.

Syntax
      LOGOFF [/f] [/n] 

Key
   /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.