@echo off
Setlocal EnableExtensions
Set infile=%1
Set find=что_меняем
Set replace=на_что_меняем
SetLocal EnableDelayedExpansion
for /f "usebackq delims= eol=" %%n in (!infile!) do (
set LINE=%%n
set TMPR=!LINE:%find%=%replace%!
Echo !TMPR!>>!infile!-TMP.TXT
)
copy %infile% %infile%.bak
move %infile%-TMP.TXT %infile%