Linux之系统管理员笔记

1.查看最近一次启动时间

who -b
system boot  2014-07-27 18:48

2.who命令实现带有“表头”的查询结果

who -H 
NAME     LINE         TIME             COMMENT
root     pts/1        2017-10-19 09:29 (22.113.28.213)
root     pts/2        2017-10-19 15:16 (117.132.10.124)

3.通过who命令来查看运行级别

who -r
 run-level 3  2017-07-27 18:48

4.who命令查看带有消息状态标志的结果（+：表示可接受消息；-：表示禁止接收消息）

who -T
root     + pts/1        2017-10-19 09:29 (22.112.24.213)
root     + pts/2        2017-10-19 15:16 (111.121.10.194)

5.通过who命令查看服务器登录记录

last -f /var/log/wtmp

 

6.查看当前终端是否允许被访问

mesg
is y

7.禁止当前终端被访问

mesg n

 

8.通过write命令实现终端间的交互

#lisi pts/2
write zhagnsan pts/3
hello,what are u doing

 这时张三所在终端会显示

Message from lisi@localhost on pts/2 at 15:55 ...

hello,what are u doing

注意：接收方想重新回到cli，enter即可。crtl+d即可结束会话。

 

9.下载网页保存到文件并记录日志

wget -o quote.log -O Daily_Quote.html $url

-o 记录日志

-O 自定义文件名

 10.检测一个网址是否有效

wget --spider www.baidu.com
Spider mode enabled. Check if remote file exists.
--2017-10-19 17:50:01--  http://www.baidu.com/
Resolving www.baidu.com... 115.239.211.112, 115.239.210.27
Connecting to www.baidu.com|115.239.211.112|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 277 [text/html]
Remote file exists and could contain further links,
but recursion is disabled -- not retrieving.

 更为简洁的方式：

wget -nv --spider www.baidu.com
2017-10-19 17:53:32 URL: http://www.baidu.com/ 200 OK