实现简单sed替换功能的python脚本

#可以用来修改配置文件参数

 # -*- coding:utf-8 -*-
 import os,sys
 old = sys.argv[1]
 new = sys.argv[2]
 file = sys.argv[3]
 file2 = sys.argv[3]
 tmp_file ="tmpfile"
 f = open(file,"r")
 f2 = open(tmp_file,"r+")
 for line in f:
     if old in line:
         line= str.replace(line,old,new)
         f2.write(line)
     f2.write(line)
     f2.flush()
 f.close()
 f2.close()

 os.remove(file)
 os.rename(tmp_file,file2)

好用的sed

 def sed_file(file_name,old,new):
     f = open(file_name)
     f2 = open("%s.bak"%file_name,"a+")
     for line in f:
         if line.startswith(old):
             line = str.replace(line,old,new)
             f2.write(line)
             f2.flush()
             continue
         f2.write(line)
         f2.flush()

     f.close()
     f2.close()

     os.remove(file_name)
     os.rename("%s.bak"%file_name,file_name)