Linux Check port occupancy status (super detailed)

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1. Use netstat Instruction

netstat is a command used to display network status information. To see if a specific port is occupied, you can use the following command:

netstat -tuln | grep 端口号

• -t: Display TCP connection information
• -u: Display UDP connection information
• -l: Only show ports in listening status
• -n: Use numeric format to display the port number instead of the service name
• grep 端口号: Use the grep command to filter out the specified port number information

For example, to check whether port number 80 is occupied, you can execute:

netstat -tuln | grep 80

2. Use ss Instruction

ss is a more modern tool for displaying socket statistics. It is faster and more efficient than netstat . To check the port usage, you can use the following command:

ss -tuln | grep 端口号

• -t: Display TCP connection information
• -u: Display UDP connection information
• -l: Only show ports in listening status
• -n: Use numeric format to display the port number instead of the service name
• grep 端口号: Use the grep command to filter out the specified port number information

For example, to check whether port number 80 is occupied, you can execute:

ss -tuln | grep 80

3. View all port occupancy status

If you want to view the occupancy of all ports on the system, just omit the grep command:

Use netstat:

netstat -tuln

Used by someone ss：

ss -tuln

This will show all TCP and UDP ports listening.

at last

Now you have learned how to check the port usage on your Linux system! This is useful for diagnosing network problems and understanding system status.