1.首先查看当前账户

[hadoop@weekend01 ~]$ who

hadoop   tty1         2016-11-14 09:31 (:0)

hadoop   pts/0        2016-11-14 09:32 (:0.0)

hadoop   pts/1        2016-11-14 09:35 (:0.0)

hadoop   pts/2        2016-11-14 09:35 (:0.0)

hadoop   pts/3        2016-11-14 09:35 (:0.0)

hadoop   pts/4        2016-11-14 09:35 (:0.0)

hadoop   pts/5        2016-11-14 09:35 (:0.0)

hadoop   pts/6        2016-11-14 09:35 (:0.0)

查询每个用户最近登陆时间lastlog

Username         Port     From             Latest

root             pts/7    192.168.1.119    Wed Nov  9 12:57:40 +0800 2016

2.向所有用户广播一跳消息

[hadoop@weekend01 ~]$ wall "Hello,everyone I am sishen,what's your name?"

Broadcast message from hadoop@weekend01 (pts/0) (Mon Nov 14 10:01:59 2016):

Hello,everyone I am sishen,what's your name?

[hadoop@weekend01 ~]$

Broadcast message from hadoop@weekend01 (pts/0) (Mon Nov 14 10:01:59 2016):

Hello,everyone I am sishen,what's your name?

这样pts/0到pts/6都可以收到这条消息

3.向指定用户发送消息，使用write命令

[hadoop@weekend01 ~]$ who

hadoop   tty1         2016-11-14 09:31 (:0)

hadoop   pts/0        2016-11-14 09:32 (:0.0)

hadoop   pts/1        2016-11-14 10:08 (:0.0)

hadoop   pts/2        2016-11-14 10:08 (:0.0)

hadoop   pts/3        2016-11-14 10:08 (:0.0)

hadoop   pts/4        2016-11-14 10:08 (:0.0)

hadoop   pts/5        2016-11-14 10:08 (:0.0)

hadoop   pts/6        2016-11-14 10:08 (:0.0)

root     pts/7        2016-11-14 10:08 (192.168.1.119)

root     pts/8        2016-11-14 10:20 (192.168.1.119)

root     pts/9        2016-11-14 10:19 (192.168.1.119)

root     pts/10       2016-11-14 10:21 (weekend06)

[root@weekend06 ~]# ssh weekend01

[hadoop@weekend01 ~]$ write root pts/10

Hello,I am sishen,What's your name?

[root@weekend01 ~]#

Message from root@weekend01 (as hadoop) on pts/9 at 10:21 ...

Hello,I am sishen,What's your name?

使用Ctrl+d来结束对话

如果不想接收消息可以使用

[root@weekend01 ~]# mesg n来关闭，这样除了root之外的信息就不会接收了

也可以使用

[hadoop@weekend01 ~]$ who

hadoop   tty1         2016-11-14 09:31 (:0)

hadoop   pts/0        2016-11-14 09:32 (:0.0)

hadoop   pts/1        2016-11-14 10:08 (:0.0)

hadoop   pts/2        2016-11-14 10:08 (:0.0)

hadoop   pts/3        2016-11-14 10:08 (:0.0)

hadoop   pts/4        2016-11-14 10:08 (:0.0)

hadoop   pts/5        2016-11-14 10:08 (:0.0)

hadoop   pts/6        2016-11-14 10:08 (:0.0)

[hadoop@weekend01 ~]$ echo  "hello ,what are you doing?" >/dev/pts/3

[hadoop@weekend04 ~]$ hello ,what are you doing?