$ who
root     tty1         Aug 18 15:16
user1    tty2         Aug 18 21:26
john     :0           Aug 18 10:52
john     pts/0        Aug 18 10:52 (:0.0)
john     pts/1        Aug 18 10:52 (:0.0)
$

who: output explained
In a graphical display environment (X11) a non-graphical application like a Shell can be executed using a terminal emulator (e.g. xterm). In the example above user “john” is logged in at local display “:0” running two terminal emulator sessions. Each terminal emulator has its own “pseudo terminal” (pts/0, pts/1).

Copyright © 2004 Integrated Services; tux4u.nl
Author: ing. J.M. Waldorp; process-cycle.html 2004-11-01