Detailed explanation of port occupancy check operation in Linux

Detailed explanation of port occupancy check operation in Linux

In the Linux operating system, network communication is realized through ports, and different ports correspond to different network services or application. During the development or operation and maintenance process, we often encounter the need to check whether a certain port is occupied to ensure that the service can start normally. This article will introduce in detail how to check port occupancy in a Linux environment, including code examples written using command line tools and programming languages.

1. Use command line tools to check port occupancy

1. netstat command

netstat is a command line tool used to display network status information. Through it, you can view the open ports and corresponding processes in the system. The following are some common options for the netstat command:

• -t: Display TCP ports
• -u: Display UDP ports
• -n: Display number format (not Resolve domain name)
• -p: Display process identifier and process name

By combining these options, you can use the following command to view all listening ports and corresponding processes in the system:

netstat -tulnp

2. ss command

ss is an alternative tool to netstat, with better performance and simpler usage. Similar to netstat, ss can also check port occupancy. The following is an example of a commonly used ss command:

ss -tlnp

This command will display all TCP ports in the listening state and the corresponding processes in the system.

2. Use programming language to write code to check port occupancy

In addition to command line tools, we can also use programming language to write code to check port occupancy. The following uses Python as an example to show how to check port occupancy through the programming language.

import socket def check_port(port): try: s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.bind(("0.0.0.0", port)) s.close() return True except Exception as e: return False port_to_check = 8080 if check_port(port_to_check): print(f"端口 {port_to_check} 可用") else: print(f"端口 {port_to_check} 已被占用")

The above is a simple Python script that checks whether the specified port is occupied by creating a socket connection. By calling the check_port function and passing in the port number to be checked, the occupancy of the port can be obtained.

Summary:

This article details how to check port occupancy through command line tools and programming languages in the Linux environment. By using netstat, ss commands or writing Python code, we can easily obtain the port occupancy status, helping us ensure the normal startup and operation of system services. I hope the above content will be helpful to readers in practical work.

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