count_log.py

#!/usr/bin/env python

import time
import subprocess
import select

filename = '/home/ubuntu/log/rel_stash.log'

f = subprocess.Popen(['tail','-n 20',filename],\
        stdout=subprocess.PIPE,stderr=subprocess.PIPE)
p = select.poll()
p.register(f.stdout)

counts = []
for i in range(0,21):
    if p.poll(1):
        if ":" in  f.stdout.readline():
            counts.append(f.stdout.readline())
    time.sleep(1)

begin = int((counts[0]).split(" ")[-1])
begin_line = counts[0]
end   = int((counts[-1]).split(" ")[-1])
end_line = counts[-1]
diff = end - begin

result = """
start {},
end {},
diff {}
""".format(begin_line, end_line, diff)

file = open("/home/ubuntu/log