BAT修改文本内容

@echo off
(for /f "delims=" %%a in (文件名) do (
set "str=%%a"
setlocal enabledelayedexpansion
set "str=!str:老字符串=新字符串!"
echo,!str!
endlocal
))>"setup.tmp"
move /y "tmp.tmp" "文件名"