1 # -*- coding:utf-8 -*-
 2 import os,sys
 3 old = sys.argv[1]
 4 new = sys.argv[2]
 5 file = sys.argv[3]
 6 file2 = sys.argv[3]
 7 tmp_file ="tmpfile"
 8 f = open(file,"r")
 9 f2 = open(tmp_file,"r+")
10 for line in f:
11     if old in line:
12         line= str.replace(line,old,new)
13         f2.write(line)
14     f2.write(line)
15     f2.flush()
16 f.close()
17 f2.close()
18 
19 os.remove(file)
20 os.rename(tmp_file,file2)