#本脚本通过执行python脚本(3.0)，实现shell的sed字符串替换功能

#!/usr/bin/env python
# -*- UTF-8 -*-
# Author:Jerry
import sys
import os
import shutil
parameters=sys.argv
if len(parameters) !=4:
sys.exit("usage:sed.py old_text new_text file_name")
else:
py_scripts,old_text,new_text,file_name=parameters
if not os.path.exists(file_name):
sys.exit("文件 %s 不存在" % file_name)
else:
if os.path.isabs(file_name):
file_full_name=file_name
else:
file_full_name=os.path.realpath(file_name)
file_name=os.path.basename(file_full_name)
file_path=os.path.dirname(file_full_name)
backup_file=os.path.splitext(file_name)[0]+"_bak"+os.path.splitext(file_name)[1]
backup_file_name=file_path+os.path.sep+backup_file
shutil.copy(file_full_name,backup_file_name)
with open(file_full_name,'w',encoding='utf-8') as f,open(backup_file_name,'r',encoding='utf-8') as bak:
for line in bak:
f.write(line.replace(old_text,new_text))
file=open(file_full_name,'r',encoding='utf-8')
for i in file:
print(i.strip())
file.close()