Daemon thread

#!/usr/bin/python

import threading
import time

class Update(threading.Thread):
    def __init__(self):
        threading.Thread.__init__(self)

    def run(self):
        while True:
            with open('/tmp/log.txt', 'w') as f:
                f.write('%d\n' % time.time())
                time.sleep(1.0)

continous = Update()
continous.daemon = True
continous.start()