Index: uspace/app/date/date.c
===================================================================
--- uspace/app/date/date.c	(revision e34111072568504c0b5937e096001777dd84f73b)
+++ uspace/app/date/date.c	(revision 0885f7e7ca67ef126dce91bf140c9ec7e9f04289)
@@ -59,4 +59,5 @@
 	sysarg_t      battery_ok;
 	struct tm     t;
+	int           n_args = argc;
 
 	while ((c = getopt(argc, argv, "hd:t:")) != -1) {
@@ -66,10 +67,20 @@
 			return 0;
 		case 'd':
+			if (wdate) {
+				usage();
+				return 1;
+			}
 			wdate = (char *)optarg;
 			read_only = false;
+			n_args -= 2;
 			break;
 		case 't':
+			if (wtime) {
+				usage();
+				return 1;
+			}
 			wtime = (char *)optarg;
 			read_only = false;
+			n_args -= 2;
 			break;
 		case '?':
@@ -77,4 +88,10 @@
 			return 1;
 		}
+	}
+
+	if (n_args != 1) {
+		printf(NAME ": Unrecognized parameter\n");
+		usage();
+		return 1;
 	}