ok, "who -u" will not show you the processes of a user, but rather *where* he's logged in
e.g.
Code:
# who -u
root tty1 Jun 14 05:54 00:03 9353
mat :0 Jun 14 05:54 ? 9391
mat pts/1 Jun 14 05:55 . 9538
so, root is logged in on terminal 1
and mat is logged in on X server display :0 and has an terminal window (like xterm or konsole) open.
now, to force mat to logout, simply kill the x-server process by issuing
# kill 9391
Mat