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#!/usr/bin/env python

import os

import sys

def get_last_n_lines(logfile, n):

blk_size_max = 4096

n_lines = []

with open(logfile, 'rb') as fp:

fp.seek(0, os.SEEK_END)

cur_pos = fp.tell()

while cur_pos > 0 and len(n_lines) < n:

blk_size = min(blk_size_max, cur_pos)

fp.seek(cur_pos - blk_size, os.SEEK_SET)

blk_data = fp.read(blk_size)

assert len(blk_data) == blk_size

lines = blk_data.split('\n')

# adjust cur_pos

if len(lines) > 1 and len(lines[0]) > 0:

n_lines[0:0] = lines[1:]

cur_pos -= (blk_size - len(lines[0]))

else:

n_lines[0:0] = lines

cur_pos -= blk_size

fp.seek(cur_pos, os.SEEK_SET)

if len(n_lines) > 0 and len(n_lines[-1]) == 0:

del n_lines[-1]

return n_lines[-n:]

def main():

if len(sys.argv) != 3:

sys.exit('usage: %s logfile n_lines' % sys.argv[0])

for line in get_last_n_lines(sys.argv[1], int(sys.argv[2])):

print line

if __name__ == '__main__':

main()

Linux平台有一个tail命令，tail -f filename.log 就会打印文件最后新增加的内容e5a48de588b63231313335323631343130323136353331333361306461

这个也可以