windows 更改后缀名的bat

更改文件名的bat，桌面创建.txt然后更改后缀名为.bat,复制粘贴进取使用即可

@echo -----------change file prefix---------

@echo off

set before=
set /p before=before suffix:  


set after=
set /p after=after suffix:

ren *.%before% *.%after%