Bash script to kill a process via PID

Question

I am making a basic bash script. I am trying to get a PID value and store it in a variable. I got my script setup like this:

getPID = pgrep -f app.jar
kill -9 $getPID

And then, I realized that I was only printing pgrep -f app.jar onto the terminal. So I tried:

getPID = $(pgrep -f app.jar)
kill -9 $getPid

And still no luck, is there a way to get pgrep value and store it in the variable?
I came across multiple questions. And still no luck. I also tried this, not too sure what does $$ does.

pgrep -f app.jar
getPid = $$
kill $getPid

I am using Ubuntu 16.04 terminal.

http://shellcheck.net/ will catch your problem here. (You can't have spaces around `=` in an assignment). — Charles Duffy, Mar 13 '17 at 23:47
... isn't the best idea using `SIGKILL` e.g. the `-9`. It really kills the process immediatelly and the program couldn't handle the correct termination... Just use `kill` without any number - the default is `-15` e.g. `SIGTERM`, and only if absolutely needed use the `-9`. — clt60, Mar 13 '17 at 23:48
Thanks jm666, yeah one of my colleagues was telling me to use ```SIGTERM``` instead of `SIGKILL`. Unless the program is not really closing properly, but thanks for the advice.. — IntFooBar, Mar 14 '17 at 14:06

score 4 · Accepted Answer · edited May 23 '17 at 12:09

$$ stands for the PID of the current shell, not the output of the previous command.

The correct way of capturing the output of pgrep into a variable is:

getPid=$(pgrep -f app.jar)  # note: no spaces around =
kill $getPid

To make it more resilient to pgrep finding no matching processes, do:

getPid=$(pgrep -f app.jar)
[[ $getPid ]] && kill $gitPid

Or you can use pkill to do this in one shot:

pkill -f app.jar

Bash script to kill a process via PID

1 Answers1