diff --git a/cansequence.c b/cansequence.c
index 63322b8..5d09e8a 100644
--- a/cansequence.c
+++ b/cansequence.c
@@ -273,7 +273,7 @@ int main(int argc, char **argv)
 		{ 0, 0, 0, 0 },
 	};
 
-	while ((opt = getopt_long(argc, argv, "ei:pq::rvh", long_options, NULL)) != -1) {
+	while ((opt = getopt_long(argc, argv, "ei:pq::rvh?", long_options, NULL)) != -1) {
 		switch (opt) {
 		case 'e':
 			extended = true;
@@ -312,6 +312,7 @@ int main(int argc, char **argv)
 			break;
 
 		case 'h':
+		case '?':
 			print_usage(basename(argv[0]));
 			exit(EXIT_SUCCESS);
 			break;