singleapp.py

import fcntl
import time
import sys


lock = file('singleapp.lock', "w+")
try:
    fcntl.lockf(lock, fcntl.LOCK_EX|fcntl.LOCK_NB)
except Exception, e:
    print "kill me before start again"
    sys.exit(0)
while(1):
    time.sleep(1)