ss命令用來顯示處於活動狀態的套接字信息。功能和netstat類似，但比netstat更快更高效。
ss -h
Usage: ss [ OPTIONS ]
ss [ OPTIONS ] [ FILTER ]
-h, --help this message
-V, --version output version information
-n, --numeric don't resolve service names 不解析服務名稱
-r, --resolve resolve host names 解析主機名
-a, --all display all sockets
-l, --listening display listening sockets 展示監聽套接字
-o, --options show timer information 顯示計時器信息
-e, --extended show detailed socket information 顯示詳細套接字信息
-m, --memory show socket memory usage
-p, --processes show process using socket 顯示進程消息
-i, --info show internal TCP information
-s, --summary show socket usage summary 摘要信息
-4, --ipv4 display only IP version 4 sockets
-6, --ipv6 display only IP version 6 sockets
-0, --packet display PACKET sockets
-t, --tcp display only TCP sockets
-u, --udp display only UDP sockets
-d, --dccp display only DCCP sockets
-w, --raw display only RAW sockets
-x, --unix display only Unix domain sockets
-f, --family=FAMILY display sockets of type FAMILY
-A, --query=QUERY, --socket=QUERY
QUERY := {all|inet|tcp|udp|raw|unix|packet|netlink}[,QUERY]
-D, --diag=FILE Dump raw information about TCP sockets to FILE
-F, --filter=FILE read filter information from FILE
FILTER := [ state TCP-STATE ] [ EXPRESSION ]查看進程監聽端口
ss -pl