Best way to kill processes created by bash script?

Question

I have a script running in a server and it will create many sub-processes( around 800 ). I want to kill them all in one stretch. Below is the ps information.

root     26363  0.0  0.0 119216  1464 ?        Ss   Mar02   0:00 SCREEN -S website_status
root     26365  0.0  0.0 108472  1844 pts/12   Ss   Mar02   0:00  \_ /bin/bash
root      4910  0.0  0.0 161684  1956 pts/12   S    Mar02   0:00      \_ su webmon
webmon    4939  0.0  0.0 108472  1924 pts/12   S+   Mar02   0:00          \_ bash
webmon    1094  3.4  0.0 107256  2432 pts/12   S    05:37   2:26              \_ sh /home/webmon/scripts/for_html/website/website_status.sh
webmon    5159  0.0  0.0 100956  1288 pts/12   S    05:37   0:00                  \_ mysql -vvv -h 192.168.12.38 -uwebmon -px xxxxxxxxxxxxx -e show processlist;
webmon    5160  0.0  0.0 103252   816 pts/12   S    05:37   0:00                  \_ grep in set
webmon    5161  0.0  0.0 105952   900 pts/12   S    05:37   0:00                  \_ awk {print $1}
webmon   12094  0.0  0.0 100956  1288 pts/12   S    05:37   0:00                  \_ mysql -vvv -h 192.168.12.38 -uwebmon -px xxxxxxxxxxxxx -e show processlist;
webmon   12095  0.0  0.0 103252   820 pts/12   S    05:37   0:00                  \_ grep Sleep -c
webmon   15044  0.0  0.0  60240  3004 pts/12   S    05:37   0:00                  \_ ssh -q 192.168.12.38 uptime | grep -o load.* | cut -f2 -d:
webmon   15166  0.0  0.0 100956  1292 pts/12   S    05:37   0:00                  \_ mysql -vvv -h 192.168.12.38 -uwebmon -px xxxxxxxxxxxxx -e show processlist;
webmon   15167  0.0  0.0 103252   816 pts/12   S    05:37   0:00                  \_ grep in set
webmon   15168  0.0  0.0 105952   900 pts/12   S    05:37   0:00                  \_ awk {print $1}
webmon   18484  0.0  0.0 100956  1288 pts/12   S    05:38   0:00                  \_ mysql -vvv -h 192.168.12.38 -uwebmon -px xxxxxxxxxxxxx -e show processlist;
webmon   18485  0.0  0.0 103252   816 pts/12   S    05:38   0:00                  \_ grep in set
webmon   18486  0.0  0.0 105952   900 pts/12   S    05:38   0:00                  \_ awk {print $1}
webmon   25110  0.0  0.0  60240  3008 pts/12   S    05:38   0:00                  \_ ssh -q 192.168.12.38 uptime | grep -o load.* | cut -f2 -d:
webmon    2598  0.0  0.0 100956  1292 pts/12   S    05:38   0:00                  \_ mysql -vvv -h 192.168.12.38 -uwebmon -px xxxxxxxxxxxxx -e show processlist;
webmon    2599  0.0  0.0 103252   816 pts/12   S    05:38   0:00                  \_ grep in set
webmon    2600  0.0  0.0 105952   900 pts/12   S    05:38   0:00                  \_ awk {print $1}

Killing of script only didn't work out, what is the best and fastest way if I have many sub-process here?

Solution 1

Have you tried pkill -signal -P ppid?

From the pkill manual:

pkill - look up or signal processes based on name and other attributes

-signal Defines the signal to send to each matched process

-P ppid Only match processes whose parent process ID is listed

If you wanted to kill 2432, and all its children, you should first try pkill -15 -P 2432, and if that doesn't work and you're willing to use the nuclear option: pkill -9 -P 2432.

Solution 2

I made a little research and I think little explanation will help others.

So as @Schives answered, with PPID we will be able to terminate the all child and the parent process.

But how to get the PPID easily?

ps -o pid,ppid,sess,cmd -U webmon

or

root@87-109:~$ ps -o pid,ppid,sess,cmd -U webmon | grep 'website_status.sh\|PID'
  PID  PPID   SESS CMD
16848 16787  16787 sh website_status.sh
17667  4405  4405 grep --color=auto website_status.sh\|PID
root@87-109:~$

then, pkill -15 -P 16787

where webmon is the user running the process.

I came across other ways to kill parent and child process in a blog, I am pasting them here.

This requires PID,PPID,PGID,GID and how to get them?

ps -o pid,ppid,pgid,gid,sess,cmd -U username

1. kill a group of processes with negative PID(Process ID)

kill  -TERM -PID

Is to kill PID and all its child processes.

2. kill a group of processes with their PGID(Process Group ID)

kill -- -$PGID   Kill using the default signal (TERM = 15)
kill -9 -$PGID   Kill using the KILL signal (9)

3. kill a group processes with only PID info

kill -- -$(ps -o pgid= $PID | grep -o [0-9]*)

Actually, you may notice that it's just the way from #2

4. Using pkill, kill processes by PGID(Proess Group ID)

pkill -9 -g $PGID

5. Using pkill, kill processes by GID(Group ID)

pkill -9 -G $GID

6. Using pkill, kill processes by PPID(Parent Process ID)

pkill -9 -p $PPID

7. Using pkill, kill processes by terminal

pkill -9 -t $terminal

Note: without /dev/ prefix

8. Using pkill, kill processes by process name

pkill -9 -x $process_name

9. Using pkill, kill processes by session

pkill -9 -s $sess

Comments

[prado]

No. I don't want to kill the screen.

[VR_Code]

Oops I flagged this answer but did not intend to... I am not sure how to un-flag it

[terdon]

@unifex no worries, we all misclick sometimes! I dismissed the flag, but if this happens again, you can click on the "flag" link again and you should see a "retract flag" option.