How to kill a process by PID on Linux

Methods to terminate the process by PID in Linux include: 1. Use ps or pgrep to find the process PID; 2. Use the kill command to send SIGTERM (default) to try to end the process normally; 3. If there is no response, use kill -9 to send SIGKILL to force termination; 4. You can terminate multiple processes at one time or combine with pkill for batch processing; 5. After termination, it is recommended to use ps to confirm whether the process has ended. Note that normal kill should be tried first to ensure that the process can be terminated safely.

In Linux systems, terminating a process by PID (process ID) is a common system management operation. If you encounter a program that is stuck, takes up too much resources, or behaves abnormally, you can quickly end it through the command line. Here are some practical tips and considerations.

Check the PID of the process

Before terminating a process, you need to know its PID. The most common way is to use the ps or pgrep command to find:

• Use ps :

   ps aux | grep process name

  For example, if you want to find the PID of Firefox:

   ps aux | grep firefox

• Using pgrep is more straightforward:

   pgrep firefox

The first column in the output result is the corresponding PID.

Use the kill command to terminate the process

After finding the PID, you can use the kill command to send a signal to the process. By default, kill sends SIGTERM (15), indicating that the requesting process exits normally.

The basic syntax is as follows:

 kill [PID]

for example:

 kill 1234

If the process is unresponsive, you can try sending SIGKILL (9) to force termination:

 kill -9 1234

Note: SIGKILL forcefully kills the process and does not give it a chance to save data or clean up resources. It is recommended to try ordinary kill first, and then use -9 if it fails.

Other common methods and techniques

• Kill multiple processes at once
  If multiple PIDs are found, they can be listed directly:

   kill 1234 5678 9012

• Combined with pipeline batch processing
  For example, if you want to directly kill all processes named firefox :

   pkill firefox

• Confirm whether it is really killed
  After killing it, it is recommended to check whether it still exists:

   ps -p 1234

  If it prompts "Process not found", it means it has been terminated successfully.

That's basically it. By mastering these commands, you can easily handle most scenarios where processes need to be terminated based on PID. It's not complicated but easy to overlook. Don't use -9 as soon as you start. It's safer to give the program a chance to finish by itself.

The above is the detailed content of How to kill a process by PID on Linux. For more information, please follow other related articles on the PHP Chinese website!