How to search string from file using batch file?

@Echo on

    Cd /d D:\
	setlocal enabledelayedexpansion
	set "file=newabc.c"
	
	for /F "tokens=1,* delims==" %%i in ('findstr " = {"NEL1.*"   " newabc.c') do (
	::{"*BLM1.*" xyz.c')
    set "versionVar=%%~i"
    set "versionVal=%%~j"
	echo %versionVal%
	set demo=%versionval:~7,5%
	set check=%demo:~0,-3%
	echo %check%
	::set "string=!versionVal:~2,5!"
	set /a sequence=!check!+1
	echo %sequence%
	)

	for /f "tokens=1,*delims=]" %%i in ('type "%file%" ^| find /v /n "" ^& break^>%file%') do (
    set "line=%%j"
    if "!line!" == "!versionVar!=!versionVal!" set line=!versionVar!= !sequence!
    echo(!line!>>!file!
	
	)
pause