python 截取某一天的日志,简单操作

#!/usr/bin/python
#Filename: Segmentation_log.py

import re,sys

def openfile(*args):
    try:
        f=open(args[0],'r')
        try:        
            while True:
                lines = f.readlines(100)
                if not lines:
                    break
                for line in lines:
                    if(line.find(args[1])>=0):
                        writenewfile(line,args[2])
        finally:
            f.close()
            print '*'*21+"END"+"*"*21
    except IOError:
        print args[0]+" not find!"



def writenewfile(*args):
    try:
        newfile=open(args[1],'a')
        try:
            newfile.write(args[0])
        finally:
            newfile.close()

    except IOError:
        print args[1]+"not find!!"

def chuli(*args):
    print '*'*20+"START"+"*"*20
    logre=re.split('.',args[0])
    newlogfile=logre[0]+args[1]+"."+logre[1]
    openfile(args[0],args[1],newlogfile)


if __name__=='__main__':
    chuli(sys.argv[1],sys.argv[2])

有一客户发过来一个日志,谁知道太大了, 打不开,打开了,编辑器操作也很慢,好吧,自己动手.