# 命令为 lsof -i
[root@onepiece ~]# lsof -i
# 将会显示 命令 + 进程ID + 进程所属用户, 以及监听的协议、状态等信息
COMMAND  PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
dhclient 728 root 6u IPv4 11262  0t0 UDP *:bootpc
ntpd  839 ntp 16u IPv4 13671  0t0 UDP *:ntp
ntpd  839 ntp 18u IPv4 13677  0t0 UDP localhost:ntp

[root@onepiece ~]# lsof -i
-bash: lsof: command not found
[root@onepiece ~]# yum install -y lsof
......
Installed:
 lsof.x86_64 0:4.87-6.el7
Complete!
# 出现上述的 "Complete!"，说明安装成功。

[root@onepiece ~]# lsof -i:22
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
sshd 3187 root 3u IPv4 16278  0t0 TCP *:ssh (LISTEN)
sshd 9528 root 3u IPv4 4436480  0t0 TCP onepiece:ssh->120.253.xx.xx:30214 (ESTABLISHED)

# 命令如下：
[root@onepiece ~]# killall sshd
# 这样，所有sshd的进程都会被结束掉 —— 我这里通过ssh远程操作阿里云服务器, 杀死之后将退出连接, 提示如下:
Connection to 47.52.xx.xx closed by remote host.
Connection to 47.52.xx.xx closed.
# 此时需要从阿里云控制台通过终端进入, 并开启sshd服务, 命令如下:
service sshd start

# 命令示例如下：
[root@onepiece ~]# netstat -anp | grep 22
tcp  0  0 0.0.0.0:22    0.0.0.0:*    LISTEN  9646/sshd
tcp  0  36 172.31.xx.xx:22  120.253.xx.xx:30307  ESTABLISHED 9649/sshd: root@pts
unix 2  [ ]   DGRAM     15722 476/dbus-daemon
unix 3  [ ]   STREAM  CONNECTED  11122 476/dbus-daemon  

# 命令为fuser：
[root@onepiece ~]# fuser -v -n tcp 22
      USER  PID ACCESS COMMAND
22/tcp:    root  9646 F.... sshd
      root  9649 F.... sshd

[root@onepiece ~]# kill -s 9 9646(进程号)