[Iska]

Например, так:

Код:

@echo off
setlocal enableextensions enabledelayedexpansion

for /f "delims==" %%i in (list.txt) do (
	call :GetSecondLine "%%~i"
	echo %%~i: [!SecondLine!]
)

endlocal
exit /b 0

:GetSecondLine
	setlocal enableextensions enabledelayedexpansion
	
	set sOutName=%~0
	
	if exist "%~1" (
		for /f "usebackq skip=1 delims==" %%j in ("%~1") do (
			if not defined sResult set sResult=%%j
		)
	)
	
	endlocal & set %sOutName:~4%=%sResult%
	exit /b