CentOS kills process Kill method encyclopedia

The safest way to kill a process is simply to use the KILL command.

First use the PS-EF command to determine the PID to kill the process, and then enter the following command:
# Kill-pid
Note: The standard KILL command usually achieves the purpose. Terminate the problematic process and release the resources of the process to the system. However, if a process starts a child process and kills only the parent process, the child process is still running and therefore consumes resources.
To prevent these so-called "zombie processes", be sure to kill all of their child processes before killing the parent process.

* Determine the PID or ppid to kill the process
# Ps-ef | grep httpd
* End the process in an elegant way
# kill-l PID
The-l option tells the kill command to end the process as if the user who started the process has logged off. When this option is used, the kill command attempts to kill the left child process as well.
But this command is not always successful-it may still be necessary to manually kill the subprocess before killing the parent process.

*term Signal
Sends a term signal to the parent process, trying to kill it and its child processes.
# kill-term PPID

*killall command
The killall command kills all processes within the same process group. It allows you to specify the name of the process to terminate, not the PID.
# Killall HTTPD

* Stop and restart the process as follows:

# Kill-hup PID
This command lets the Linux gentle execution process shut down and then reboot immediately.
This command is handy when you configure your application, and you can execute this command when you need to reboot after modifying the profile (for example, restart Nginx often use this command).

* Must kill technology kill-9 PID

When using this command, be sure to confirm with ps-ef that there are no zombie processes left. Zombie processes can only be eliminated by terminating the parent process. If the zombie process is adopted by INIT, the problem is more serious. Killing the init process means shutting down the system.

If there is a zombie process in the system, and its parent process is init, and the zombie process consumes a large amount of system resources, it is necessary to reboot the machine at some point to clear the process table.