in the line syntax, at the beginning theres
set pass=%1
set user=%2
a batch file always knows what its name is %0 is its name, these are variables set inside a open batch file, %0 is the name of the batch file, in the syntax there is line positions
%0 %1 %2 %3 %4 %5 %6 %7 %8 %9 so for example if = %0 /? = %1
the next part with if statement, its the same thing as typing if %input%==asus goto bd only its set in an if array , an array is started with ( and ended with )
for example
::1 if "%user%"=="password" (
::2 if "%user%"=="password" (
goto second
) ELSE (
::3
if "%user%"=="password" (
goto second
::4::ELSE is another part of the if statement, example:
:: if "%var%"=="ok" goto good ELSE goto fail
) ELSE (
::5 if "%user%"=="password" (
goto second
) ELSE (
goto fail
)