老男孩教育每日一题-2017年4月7日-请给出linux中查看系统已经登录用户的命令

[root@show regular]# w
20:01:54 up 6 days, 46 min,  5 users,  load average: 0.00, 0.00, 0.00
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/0    10.0.0.1         08:23    0.00s  0.43s  0.00s w
root     pts/1    10.0.0.1         20:01    5.00s  0.00s  0.00s -bash
root     pts/2    10.0.0.1         20:01    4.00s  0.01s  0.01s -bash
root     pts/3    10.0.0.1         20:01    3.00s  0.00s  0.00s -bash
root     pts/4    10.0.0.1         20:01    2.00s  0.00s  0.00s -bash

w不只能看用户的登录状态，还能看他们在执行什么命令。
同时还可以看当前系统运行了多久和系统负载----第一行就行  这个相当于uptime命令。

[root@show ~]# who
root     pts/0        2017-04-07 08:23 (10.0.0.1)
root     pts/1        2017-04-07 20:01 (10.0.0.1)
root     pts/2        2017-04-07 20:01 (10.0.0.1)
root     pts/3        2017-04-07 20:01 (10.0.0.1)
root     pts/4        2017-04-07 20:01 (10.0.0.1)
root     pts/5        2017-04-07 21:10 (10.0.0.1)

[root@show ~]# last |head -20
root     pts/5        10.0.0.1         Fri Apr  7 21:10   still logged in
root     pts/4        10.0.0.1         Fri Apr  7 20:01   still logged in
root     pts/3        10.0.0.1         Fri Apr  7 20:01   still logged in
root     pts/2        10.0.0.1         Fri Apr  7 20:01   still logged in
root     pts/1        10.0.0.1         Fri Apr  7 20:01   still logged in
root     pts/0        10.0.0.1         Fri Apr  7 08:23   still logged in
root     pts/0        10.0.0.1         Thu Apr  6 08:25 - 22:16  (13:50)
root     pts/1        10.0.0.1         Wed Apr  5 20:26 - 10:16  (13:50)
root     pts/0        10.0.0.1         Tue Apr  4 23:12 - 21:52  (22:39)
root     pts/1        10.0.0.1         Fri Mar 31 20:36 - 09:46  (13:09)
root     pts/0        10.0.0.1         Fri Mar 31 15:47 - 21:55  (06:08)
root     pts/0        10.0.0.1         Fri Mar 31 15:36 - 15:47  (00:11)
reboot   system boot  2.6.32-573.8.1.e Fri Mar 31 15:35 - 21:12 (7+05:36)
root     pts/0        10.0.0.1         Thu Mar 30 08:02 - 22:26  (14:24)
root     pts/1        10.0.0.1         Wed Mar 29 22:24 - 10:06  (11:42)
root     pts/0        10.0.0.1         Tue Mar 28 21:50 - 00:02 (1+02:11)
root     pts/0        10.0.0.1         Mon Mar 27 18:16 - 13:49  (19:32)
root     pts/4        10.0.0.1         Sun Mar 26 22:29 - 10:11  (11:42)
root     pts/3        10.0.0.1         Sun Mar 26 08:00 - 10:11 (1+02:10)
root     pts/2        10.0.0.1         Sun Mar 26 07:51 - 08:43 (1+00:51)

still logged in
就表示，现在正在远程登录的用户

[root@show ~]# lastlog
Username         Port     From             Latest
root             pts/5    10.0.0.1         Fri Apr  7 21:10:15 +0800 2017
bin                                        **Never logged in**
daemon                                     **Never logged in**
adm                                        **Never logged in**
lp                                         **Never logged in**
sync                                       **Never logged in**
shutdown                                   **Never logged in**
halt                                       **Never logged in**
mail                                       **Never logged in**
uucp                                       **Never logged in**
operator                                   **Never logged in**
games                                      **Never logged in**
gopher                                     **Never logged in**
ftp                                        **Never logged in**
nobody                                     **Never logged in**
dbus                                       **Never logged in**
vcsa                                       **Never logged in**
abrt                                       **Never logged in**
haldaemon                                  **Never logged in**
ntp                                        **Never logged in**
saslauth                                   **Never logged in**
postfix                                    **Never logged in**
sshd                                       **Never logged in**
tcpdump                                    **Never logged in**
nginx                                      **Never logged in**
ntop                                       **Never logged in**
www                                        **Never logged in**
oldgirl                                    **Never logged in**