Attempt to completely fork from parent process.

fork.py

#!/usr/bin/python
import time, os, sys

# do the UNIX double-fork magic
pid = os.fork() 
if pid > 0:
	# parent process, exit
	sleep(5)
	sys.exit(0)

# os.setsid()

# do second fork
pid = os.fork() 
if pid > 0:
	# exit from second parent
	sleep(10)
	os._exit(os.EX_OK)

# do stuff
time.sleep(15)

# all done
os._exit(os.EX_OK)