sub check_input {
	my ($type, $input) = @_;

	return $input if length($input) != 1;
	exit if $input eq 'q'; # etc for universal options

	# handle prompt types
	if ($type eq 'start') {
		if ($input eq 'n') {
			# do something useful with currently out-of-scope variables
			...
			# (uh oh)
		}
	}
	# etc, etc
}