Kill a running shell script, and kill all process running within it

I have a shell script running in the background, which runs 5 different jobs. When I run the shell script all 5 jobs start running in order. When I kill this shell, whichever process is running, will still continue to run, even though I have killed the shell. $ bash shell.sh & echo $! this gives me the PID of the shell, which allows me to kill it later if I wish to do so at some point. #!/bin/bash JOB1 JOB2 JOB3 JOB4 JOB5 How can I make the shell kill all process running within, once it has been killed?