#!/usr/bin/env python
import time
import os

def run(file_name):
    data = ''
    last_data_len = len(data)
    last_size = os.stat(file_name).st_size

    while True:
        st_size = os.stat(file_name).st_size
        if st_size != last_size:
            print 'size changed @ %s' % time.asctime()

        data = open(file_name).read()

        if len(data) != last_data_len:
            print 'new data arrived @ %s' % time.asctime()
            print repr(data[-50:])


        if '\0' in data:
            first_index = data.index('\0')
            data_fragment = data[first_index-50:first_index+50]
            print 'Detected NULL @ %d %s' % (first_index, repr(data_fragment))
            break

        time.sleep(0.250)

        last_data_len = len(data)
        last_size = st_size

if __name__ == '__main__':
    run('test-nfs')