who

查看當前系統中當前登錄的帳戶

$who
jiang    :0           2016-10-13 08:55 (:0)
jiang    pts/4        2016-10-13 09:03 (:0)
jiang    pts/1        2016-10-13 09:00 (:0)
jiang    pts/6        2016-10-13 09:59 (:0)

如果在tty7里$su，那麼$who不會識別root，需要在tty1里登錄$su root，就可以在任何終端里執行$who查看到root用戶

$su
# who
jiang    :0           2016-10-13 08:55 (:0)
jiang    pts/1        2016-10-13 10:01 (:0)

#切換到tty1里登錄root
$su
#再切換回來
# who
jiang    :0           2016-10-13 08:55 (:0)
root     tty1         2016-10-13 14:44
jiang    pts/1        2016-10-13 10:01 (:0)

#切換到tty1里退出root
$exit
#再切換回來
# who
jiang    :0           2016-10-13 08:55 (:0)
jiang    pts/1        2016-10-13 10:01 (:0)