linux tricks

1. kill -9 PID does not release memory

I recently faced this problem. You can see in the below screen, even I used kill -9 2707867, the memory had not been released. I supposed that this process became a zoombie.

Actually, the PID shown (2707867) is the child process of a parent process, which actually was holding the memory. By using this command, I was able to find the parent process ID.

Then, we can just use kill -9 2707866 to get the memory back. Cheers :)