日常运维管理 常用命令（2）
[root@tyzz ~]# w
23:13:58 up 11 days, 9:15, 1 user, load average: 0.00, 0.01, 0.05
USER TTY LOGIN@ IDLE JCPU PCPU WHAT
root pts/0 23:03 6.00s 0.02s 0.00s w
[root@tyzz ~]# uptime
23:14:04 up 11 days, 9:15, 1 user, load average: 0.00, 0.01, 0.05
[root@tyzz ~]# ^C
[root@tyzz ~]#[root@tyzz ~]# vmstat 1 5
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
1 0 0 105532 124448 436356 0 0 1 23 5 27 0 0 99 0 0
0 0 0 105524 124448 436356 0 0 0 0 132 286 1 0 99 0 0
0 0 0 105524 124448 436356 0 0 0 0 126 272 0 0 100 0 0
4 0 0 102964 124452 436352 0 0 0 28 229 585 3 3 94 0 0
0 0 0 105276 124452 436356 0 0 0 32 227 528 2 4 94 0 0si：从交换分区到内存，so：从内存到交换分区；bi：从硬盘到内存，bo：从内存到硬盘；
如果bi,bo值很大 看是什么进程导致io高。 可以用命令 iotop 看看。如果没有这命令，yum install iotop 安装
top 动态查看
free
[root@tyzz ~]# free
total used free shared buffers cached
Mem: 1017992 898652 119340 12632 119056 420752
-/+ buffers/cache: 358844 659148
Swap: 0 0 0
[root@tyzz ~]# free -m
total used free shared buffers cached
Mem: 994 877 116 12 116 410
-/+ buffers/cache: 350 643
Swap: 0 0 0理解buffer cache
buffer is something that has yet to be "written" to disk.
A cache is something that has been "read" from the disk and stored for later use.
[root@tyzz ~]# ps aux
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.3 41096 3160 ? Ss Feb14 1:37 /usr/lib/systemd/systemd --system --deserialize 22
root 2 0.0 0.0 0 0 ? S Feb14 0:00 [kthreadd]
root 3 0.0 0.0 0 0 ? S Feb14 0:08 [ksoftirqd/0]
root 5 0.0 0.0 0 0 ? S< Feb14 0:00 [kworker/0:0H]
root 7 0.0 0.0 0 0 ? S Feb14 0:00 [migration/0]ps aux | grep xxx 判断xxx进程 是否启动
netstat查看当前系统所有监听端口的命令是（显示数字端口）
netstat -lnp
netstat查看系统所有网络连接状况的命令是（显示数字端口）？
netstat -an
tshark 常用命令
[root@tyzz ~]# tshark -n -t a -R http.request -T fields -e "frame.time" -e "ip.src" -e "http.host" -e "http.request.method" -e "http.request.uri"
tshark: -R without -2 is deprecated. For single-pass filtering use -Y.
Running as user "root" and group "root". This could be dangerous.
Capturing on 'eth0'
"Feb 27, 2017 21:45:55.823973593 CST" 221.11.20.100 119.29.138.182 GET /
"Feb 27, 2017 21:45:55.873451428 CST" 221.11.20.100 119.29.138.182 GET /noindex/css/bootstrap.min.css
"Feb 27, 2017 21:45:55.875604880 CST" 221.11.20.100 119.29.138.182 GET /noindex/css/open-sans.css
"Feb 27, 2017 21:45:56.007230812 CST" 221.11.20.100 119.29.138.182 GET /images/apache_pb.gif
"Feb 27, 2017 21:45:56.015858512 CST" 221.11.20.100 119.29.138.182 GET /images/poweredby.png
