How to check the process number and kill the process in Linux

Linux method to view and kill processes: First use the "ps -aux | grep program name" command to view the relevant processes and obtain the process number PID; then use the "kill -9 PID" command to kill it process.

The operating environment of this tutorial: Red Hat Enterprise Linux 6.1 system, Dell G3 computer.

Problem description:

Use nohup & to run the background program, the command is as follows:

nohup python server.py &

This command can keep the program running in the background (guarantee your xshell disconnected but the service will not stop)

But when restarting server.py, the server will prompt that the port is occupied

At this time, it needs to be killed first Kill the previous program and restart it.

Steps:

1. Check the process and get the process number

1) Use lsof -i:port number to view Process number (when the port number is known), for example, check the process number of port 1500:

lsof -i:1500

This PID 79297 is the process number

2) When When the system does not support lsof, you can use netstat

netstat -ntlp | grep [port]

3) When you do not know the port number but know the program name, use ps aux to view

ps -aux | grep server.py

The column that is not S corresponds to PID.

Which column Sl represents the running status STAT, and S represents interruption? Anyway, after looking it up, I don’t understand. What I understand is that S represents the temporary process number of your query command, not the process number of the program running. Generally, S, Sl or Sl represents the running program.

(In addition, I found that when using ps aux, why does other people's USER display the name, but mine displays the 515 user ID? After checking, I found that there is a problem with the Linux mechanism itself. When the user name exceeds 8 characters, the system The user's corresponding ID will be automatically displayed.)

2. Kill him

kill -9 PID

Remarks ：

1) The process name can be queried according to the PID. The command is as follows:

ll /proc/PID

This way you can locate the path of the running program

Related recommendations:《Linux video tutorial》

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