This is a naughty script that mimics linux watch command on Mac OS X.

watch.py

import os
import sys
import time


"""This is a naughty script 
   to mimic linux watch process 
   in Mac OS X terminal. It might be
   useful for other *BSD family.
"""


def run_watch(unix_command, delay_time):

	while True:
	
		os.system("clear")
		os.system(unix_command)
	
		time.sleep(float(delay_time))


def main():

	if len(sys.argv) != 3:

		print "python watch.py <UNIX_CMD> <DELAY_TIME>"

	else:

		run_watch(sys.argv[1], sys.argv[2])


if __name__ == "__main__":

	try:
	
		main()
	
	except KeyboardInterrupt:

		print "Process ended!"
		time.sleep(2)
		os.system("clear")