How to kill a linux process using pid from php?

Question

I am facing one issue regarding killing a Linux process from my php code. I am running a Scrapy tool from my php code using the proc_open() function in the background.

It works fine, but now I want to kill this process using its process id. To do that I'm using exec("sudo kill -9 $pid"); where $pid is the process id which I'm getting from my php code.

The problem is this process is running on behalf of the apache user. I thought there might be some permissions issue, so I added apache user to the sudoers file like this apache ALL=(ALL) NOPASSWD:ALL but I'm still not able to kill it. Somehow, the same kill command works from my putty console.

My code is on an Amazon EC2 instance.

My question is, how can I kill that process identified by a pid from php?

Also, if `apache` is the owner of the process, did you try simply `kill -9 $pid`? — Sudipta Chatterjee, Oct 08 '13 at 05:40
Thanks @SudiptaChatterjee.. Simply kill -9 $pid worked.. I had wasted so many days on this.. Thanks once again! — kishan, Oct 08 '13 at 06:11
Also, never use kill -9 - it can mess up all sorts of things, much better practice to use kill -15 and wait a little, and then only as a last resort, use kill -9. — Brian C, Jan 27 '20 at 02:39

score 28 · Accepted Answer · answered Oct 08 '13 at 06:18

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Never, ever, give apache sudo permissions!

Use exec("kill -9 $pid"); - your apache process started it, it can kill it :)

answered Oct 08 '13 at 06:18

Sudipta Chatterjee

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i couldn't do it with exec so i just needed to use shell_exec but anyway thanks it helped me a lot :) – virusivv Dec 21 '15 at 00:29
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Don't use `exec()` for this, use `posix_kill()` instead. Also, it's bad practice to routinely use kill -9 as it forces the process to die instantly without cleanup (see other answer). Instead, reserve kill -9 for when a process won't die. with kill -15 or kill -1 (SIGHUP). – Brian C Jan 27 '20 at 02:42

score 10 · Answer 2 · edited Jun 20 '20 at 09:12

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Try posix_kill:

bool posix_kill ( int $pid , int $sig )
Send the signal sig to the process with the process identifier pid.

edited Jun 20 '20 at 09:12

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answered Jun 01 '16 at 18:34

Viacheslav aka Lordz

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score 0 · Answer 3 · edited May 23 '17 at 11:54

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You can use exec with sudo privileges for skill that is more safer check out kill users processes in linux with php

Thanks & Regards,
Alok Thaker

edited May 23 '17 at 11:54

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answered Oct 08 '13 at 05:51

linux_fanatic

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skill is obsolete? pkill is something you should look at. – MarcoZen Feb 11 '14 at 11:54

How to kill a linux process using pid from php?

3 Answers3

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