tail.py

import sys
import time


def follow(filename):
    log_file = open(filename, 'r')
    log_file.seek(0, 2)
    while True:
        line = log_file.readline()
        if not line:
            time.sleep(0.1)
            continue
        yield line


print sys.argv[1]
for line in follow(sys.argv[1]):
    print line