Linux实现查看某一端口是否开放

[root@localhost ~]# lsof -i:6379
command      pid user   fd   type    device size/off node name
redis-ser 431717 root    4u  ipv4 133236252      0t0  tcp *:6379 (listen)

[root@localhost ~]# netstat -aptn |grep -i 6379
tcp        0      0 0.0.0.0:6379            0.0.0.0:*               listen      431717/./bin/redis- 

[root@localhost ~]# netstat -lptn |grep -i 6379
tcp        0      0 0.0.0.0:6379            0.0.0.0:*               listen      431717/./bin/redis- 

[root@localhost ~]# netstat -lpun |grep -i 6379
[root@localhost ~]# 

telnet 127.0.0.1 6379   
   trying 127.0.0.1...
   connected to 127.0.0.1.
   escape character is '^]'.