如何在 shell 脚本中杀死刚启动的 Java 进程？

Question

I have this simple script where I execute a.jar file and I'd need its PID for killing it after the sleep command:

java -jar test.jar &> output.txt & pid=$! sleep 10

The problem is: the PID changes after the application gets fully launched, this pid I get in first place is not the same PID the application has after 10 seconds sleeping (I checked it using ps ).

How can I track down the PID so that I can kill the fully launched application?

I've tried using pstree -p $pid but I get a long list of Java children processes and I thought there might be a better way to implement this other than getting every child process, extracting PID using grep and killing it, also because I'm not 100% sure this is working.

I found another solution using jps but I'd prefer use native linux commands for compatibility.

I don't necessarily need PID, using process name could be a way but I don't how to retrieve that either having only parent process' PID.

Answer 1

If you want to use process name, might run:

$ kill -9 $(ps aux | grep '[t]est.jar' | awk '{print $2}')

Options Details:

• kill : sends a kill signal (SIGTERM 15: Termination) to terminate any process gracefully.
• kill -9 : sends a kill signal (SIGTERM 9:Kill) terminate any process immediately.
• ps : listing all processes.
• grep : filtering, [p] prevent actual grep process from showing up in ps results.
• awk : gives the second field of each line, which is PID. (ps output: $1:user, $2:pid...)

Answer 2

Two ways.

1. use system. Exit() inbuilt function.

or

2. redirect the pid number to a file and use later to kill the process.

Ex:-

java -jar test.jar &> output.txt & echo $! > pid-logs
cat pid-logs | xargs kill -9