How to check which ports are occupied in Linux

How to check which ports are occupied under Linux: You can use the netstat command to check. The netstat command can display all ports and process services on the current server. Combined with the grep command, you can also view a specific port and service status.

When using Linux, you need to know which ports are currently open in the system, and to view the specific processes and users that open these ports, you can use the netstat command. Simple query.

How to check which ports are occupied under Linux:

The parameters of the netstat command are explained as follows:

　　-t : 指明显示TCP端口
　　-u : 指明显示UDP端口
　　-l : 仅显示监听套接字(所谓套接字就是使应用程序能够读写与收发通讯协议(protocol)与资料的程序)
　　-p : 显示进程标识符和程序名称，每一个套接字/端口都属于一个程序。
　　-n : 不进行DNS轮询，显示IP(可以加速操作)

can display all ports on the current server and process services. Combined with grep, you can check a specific port and service status.

netstat -ntlp   //查看当前所有tcp端口·
netstat -ntulp |grep 80   //查看所有80端口使用情况·
netstat -ntulp | grep 3306   //查看所有3306端口使用情况·

Check the program port occupancy on Linux

Use the command:

ps -aux | grep tomcat

Found that there is no Tomcat process on port 8080.

Use command:

netstat –apn

View all processes and port usage. Found the following process list, the last column of which is PID/Program name

Found that port 8080 is occupied by the Java process with PID 9658.

Further use the command: ps -aux | grep java, or directly: ps -aux | grep pid. Check

to know clearly which program is occupying port 8080! Then determine whether to use the KILL command to kill it!

Method 2: Directly use netstat -anp | grep portno

That is: netstat -anp|grep 8080

netstat -anp|grep 8080 --> tcp     0   0 0.0.0.0:8080     0.0.0.0:*  LISTEN      28500/java
ps -aux | grep 28500  --> r/local/tomcat9-jforum/tomcat

Install lsof list open files//---You can also netstat -tunlp|grep port number netstat -anp|grep port number

yum install lsof
lsof -i:8080 查看8080端口占用
lsof abc.txt 显示开启文件abc.txt的进程
lsof -c abc 显示abc进程现在打开的文件
lsof -c -p 1234 列出进程号为1234的进程所打开的文件
lsof -g gid 显示归属gid的进程情况
lsof +d /usr/local/ 显示目录下被进程开启的文件
lsof +D /usr/local/ 同上，但是会搜索目录下的目录，时间较长
lsof -d 4 显示使用fd为4的进程
lsof -i 用以显示符合条件的进程情况
lsof -i[46] [protocol][@hostname|hostaddr][:service|port]

  46 --> IPv4 or IPv6
  protocol --> TCP or UDP
  hostname --> Internet host name
  hostaddr --> IPv4地址
  service --> /etc/service中的 service name (可以不止一个)
  port --> 端口号 (可以不止一个)
  lsof -i //显示所有打开的端口
lsof -i:80 //显示所有打开80端口的进程
lsof -i -U //显示所有打开的端口和UNIX domain文件

Recommended: linux video tutorial

The above is the detailed content of How to check which ports are occupied in Linux. For more information, please follow other related articles on the PHP Chinese website!