Restarting Jack with alternative settings using script

[atmosfaere]

I am trying to use this script to kill Jack and restart it with applicable settings when my usb audio device is removed or plugged in. I am doing this using udev events and a systemd service, but even if I just run this script on it's own Jack doesn't start and stay running. The commands work perfectly fine in a terminal. Any ideas? I think it must be something to do with process management?

#!/bin/bash
killall -9 jackd jackdbus qjackctl
JACK_NO_AUDIO_RESERVATION=1 jackd -dalsa -dhw:0 -r48000 -p512 -n3 </dev/null &>/dev/null &