Fast User Switching has been a popular Panther feature in my lab where several students share one computer. However, ocassionally a user forgets to log out, and I (logged in as Administrator) have not figured out how to log them out gracefully.
While not elegant (for instance, it will not save unsaved changes in open files), here is one way to kill another user who is logged in under Fast User Switching. Assume the logged-in user is named boo. From the Terminal, type ps -axuc grep boo. In the results, look for the process called loginwindowassociated with the user boo. Note the process ID (the first column of the output) of loginwindow -- for purposes of this example, assume it was 1234. To kill the logged-in user, just type:
% sudo kill -9 1234The user will immediately disappear from the list of logged-in users. It's not elegant, but it works.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20031124125304162