CODEWITHSUNDEEP
linuxbashkill-process
user330612
user330612

Reputation: 2239

How to kill all child processes spawned by a process started from a script on kill or kill -9

I have a shell script called Launcher.sh that gets executed by a java process. The java process internally uses ProcessBuilder to execute the bash script.

Inside the Launcher.sh, I have the following code

#!/bin/bash
trap "kill -- -$$ && kill -INT -$PID" SIGINT SIGTERM SIGKILL
bash Process_A.sh &
pid=$!
echo $pid

The Process_A script will spawn another child process called Process_B.

I want to kill both Process_A and Process_B when the Launcher.sh script receives a "kill" command or "kill -9" command from its parent the java process.

So I added a trap command to trap SIGINT, SIGTERM and SIGKILL interrupts. But when I do 

kill $pid

it only kills Process_A but not the child Process_B. Both have the same PGID.

How can I kill all the child and grandchild processes spawned from my launcher.sh script correctly?

Here is an actual output of "ps j" before and after kill. Inside my script I do "dse spark" which inturn spawns a java process. I want this java process to be killed when the launcer script gets a kill signal

root@WeveJobs01:~# ps j
 PPID   PID  PGID   SID TTY      TPGID STAT   UID   TIME COMMAND
 2380  2381  2381  2281 pts/1    59265 S        0   0:00 /bin/bash
    1 58917 58916  1152 pts/0     1236 S        0   0:00 bash /usr/bin/dse spark
58917 59041 58916  1152 pts/0     1236 Sl       0   0:07 /usr/lib/jvm/java-8-oracle/jre//bin/java -cp /etc/dse/spark/:/usr/share/dse/dse-
 2381 59265 59265  2281 pts/1    59265 R+       0   0:00 ps j

root@WeveJobs01:~# kill 58917

root@WeveJobs01:~# ps j
 PPID   PID  PGID   SID TTY      TPGID STAT   UID   TIME COMMAND
 1152  1235  1235  1152 pts/0     1236 S        0   0:00 sudo -s
 1235  1236  1236  1152 pts/0     1236 S+       0   0:00 /bin/bash
    1 59041 58916  1152 pts/0     1236 Sl       0   0:23 /usr/bin/java -cp /etc/dse/spark/:/usr/share/dse/dse-
 2381 59513 59513  2281 pts/1    59513 R+       0   0:00 ps j

I tried this..and when I do "kill pid" where pid is that of the script. I get segmentation fault as it goes to infinite loop

trap 'echo "Kill All"; kill -TERM -$$' TERM INT
bash child.sh &
PID=$!
wait $PID
trap - TERM INT
wait $PID
EXIT_STATUS=$?

Upvotes: 4

Views: 3506

Answers (1)

user330612
user330612

Reputation: 2239

I need to reset kill -term in the trap statement to prevent infinite loop. This worked

trap "trap -INT && kill -- -$$"

Upvotes: 2

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