Run script when exiting LinuxCNC

Shutting down and cleaning up LinuxCNC...
Running HAL shutdown script
hm2_eth: HostMot2 ethernet driver unloaded
hm2: unloading
Note: Using POSIX realtime
igor@igor:~/Schreibtisch$ halui: emcCommandSend: no echo from Task after 5.000 seconds
halui: sendMdiCommand: failed to send mdi command 20

#!/usr/bin/python

import time
import hal
import urllib3
import atexit
import time


delta_t = 1 # seconds poll interval, hold inputs at least this long

#hal
h = hal.component("compressor")
h.newpin("active",hal.HAL_BIT,hal.HAL_IN)
h.ready()

def finaloff():
    r = http.request('GET', 'http://192.168.178.89/relay/1?turn=off')
atexit.register(finaloff)
old_start_pin_value = False
started = False
http = urllib3.PoolManager()
while True:
    time.sleep(delta_t)
    #print h["active"]
    start_pin_value = h["active"]
    if start_pin_value != old_start_pin_value:
        #print("changed")
        if started:
            started = False
            print("compressor off")
            r = http.request('GET', 'http://192.168.178.89/relay/1?turn=off')
        else:
            started = True
            print("compressor on")
            r = http.request('GET', 'http://192.168.178.89/relay/1?turn=on')
    old_start_pin_value = start_pin_value