通知并关闭指定的用户，ssh

查看当前系统的用户，who，w

$ w
15:05:42 up  4:49,  3 users,  load average: 0.02, 0.01, 0.00
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
server   tty7     :0               14:06    4:43m  1:42   0.08s pam: gdm-passwo
server   pts/0    :0.0             14:18    0.00s  0.23s  1.65s gnome-terminal
server   pts/1    :0.0             14:47    4:43   0.01s  0.01s bash

$ who
bluebird tty1         2013-08-13 14:45 (:0)
bluebird pts/0        2013-08-13 14:45 (:0.0)

通知特定用户

通过设备文件通知，设备文件可以通过who命令看到

echo "I will close your connection" > /dev/pts/2

关闭用户连接

# fuser -k /dev/pts/2