# Because user might mis-configure EFI_STUB by values like '" ", "", "foobar" ...' # We will check such mis-configuration and bailout with error. # If both is_false $EFI_STUB and is_true $EFI_STUB return false, there is # something wrong with configuration ... is_false $EFI_STUB || is_true $EFI_STUB || Error "EFI_STUB=\"$EFI_STUB\" is incorrect option value pair."