Starting and killing java app with shell script (Debian)

Question

I'm new to UNIX. I want to start my java app with a script like so:

#!/bin/sh
java -jar /usr/ScriptCheck.jar &
echo $! > /var/run/ScriptCheck.pid

This is supposedly working. It does run the app and it does write the pid file. But when I try to stop the process with a different script which contains this:

#!/bin/sh
kill -9 /var/run/ScriptCheck.pid

the console gives me this error:

bash: kill: /var/run/ScriptCheck.pid: arguments must be process or job IDs

My best guess is that I'm not writing the right code in the stop script, maybe not giving the right command to open the .pid file. Any help will be very appreciated.

Answer 1

You're passing a file name as an argument to kill when it expects a (proces id) number, so just read the process id from that file and pass it to kill:

#!/bin/sh 
PID=$(cat /var/run/ScriptCheck.pid) 
kill -9 $PID

Answer 2

A quick and dirty method would be :

kill -9 $(cat /var/run/ScriptCheck.pid)

Answer 3

Your syntax is wrong, kill takes a process id, not a file. You also should not be using kill -9 unless you absolutely know what you are doing.

kill $(cat /var/run/ScriptCheck.pid)

or

xargs kill </var/run/ScriptCheck.pid