windows 更改后綴名的bat

更改文件名的bat，桌面創建.txt然后更改后綴名為.bat,復制粘貼進取使用即可

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

@echo off

set before=
set /p before=before suffix:  


set after=
set /p after=after suffix:

ren *.%before% *.%after%