@echo off
set strOld=-t 1
set /a cpu=%number_of_processors%-1
set strNew=-t %cpu%
set file=%~dp0start.bat
setlocal enabledelayedexpansion
for /f "tokens=*" %%j in (%file%) do (
set "tmp=%%j"
if not !tmp!.==. (
set "tmp=!tmp:%strOld%=%strNew%!"
echo !tmp!>>temp.txt
)
)
move temp.txt %file%