转载自：https://mp.weixin.qq.com/s/FvmlnV-oKNxrK5glrFKPHA
如何看查占用cpu最多的进程？
方法一核心指令：ps实际命令：ps H -eo pid,pcpu | sort -nk2 | tail执行效果如下：[work@test01 ~]$ ps H -eo pid,pcpu | sort -nk2 | tail31396 0.631396 0.631396 0.631396 0.631396 0.631396 0.631396 0.631396 0.630904 1.030914 1.0结果：瞧见了吧，最耗cpu的pid=30914。
画外音：实际上是31396。
方法二
核心指令：top实际命令：topShift + t
找到了最耗CPU的进程ID，对应的服务名是什么呢？
方法一核心指令：ps实际命令：ps aux | fgrep pid执行效果如下：[work@test01 ~]$ ps aux | fgrep 30914work 30914 1.0 0.8 309568 71668 ? Sl Feb02 124:44 ./router2 –conf=rs.conf结果：瞧见了吧，进程是./router2
方法二直接查proc即可。实际命令：ll /proc/pid执行效果如下：[work@test01 ~]$ ll /proc/30914lrwxrwxrwx 1 work work 0 Feb 10 13:27 cwd -> /home/work/im-env/router2lrwxrwxrwx 1 work work 0 Feb 10 13:27 exe -> /home/work/im-env/router2/router2画外音：这个好，全路径都出来了。
如何查看某个端口的连接情况？
方法一核心指令：netstat实际命令：netstat -lap | fgrep port执行效果如下：[work@test01 ~]$ netstat -lap | fgrep 22022tcp 0 0 1.2.3.4:22022 *:* LISTEN 31396/imuitcp 0 0 1.2.3.4:22022 1.2.3.4:46642 ESTABLISHED 31396/imuitcp 0 0 1.2.3.4:22022 1.2.3.4:46640 ESTABLISHED 31396/imui
方法二核心指令：lsof实际命令：lsof -i :port执行效果如下：[work@test01 ~]$ /usr/sbin/lsof -i :22022COMMAND PID USER FD TYPE DEVICE SIZE NODE NAMErouter 30904 work 50u IPv4 69065770 TCP 1.2.3.4:46638->1.2.3.4:22022 (ESTABLISHED)router 30904 work 51u IPv4 69065772 TCP 1.2.3.4:46639->1.2.3.4:22022 (ESTABLISHED)router 30904 work 52u IPv4 69065774 TCP 1.2.3.4:46640->1.2.3.4:22022 (ESTABLISHED)