diff --git a/dev/udp/udp-perturb.c b/dev/udp/udp-perturb.c
index 824628d36..3df0f797f 100644
--- a/dev/udp/udp-perturb.c
+++ b/dev/udp/udp-perturb.c
@@ -36,6 +36,7 @@
 #include <netdb.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <getopt.h>
 #include <signal.h>
 #include <stdarg.h>
 #include <sys/stat.h>
@@ -409,31 +410,53 @@ int handle_bck(int fd, struct pollfd *pfd, struct conn *conns, int nbconn)
 	return ret;
 }
 
+/* print the usage message for program named <name> and exit with status <status> */
+void usage(int status, const char *name)
+{
+	if (strchr(name, '/'))
+		name = strrchr(name, '/') + 1;
+	die(status,
+	    "Usage: %s [-h] [options] [<laddr>:]<lport> [<saddr>:]<sport>\n"
+	    "Options:\n"
+	    "  -h           display this help\n"
+	    "  -r rate      reorder/duplicate/lose around <rate>%% of packets\n"
+	    "  -s seed      force initial random seed (currently %#x)\n"
+	    "", name, prng_state);
+}
+
 int main(int argc, char **argv)
 {
 	struct errmsg err;
 	struct pollfd *pfd;
+	int opt;
 	int i;
 
 	err.len = 0;
 	err.size = 100;
 	err.msg = malloc(err.size);
 
-	if (argc < 3)
-		die(1, "Usage: %s [<laddr>:]<lport> [<saddr>:]<sport> [rand_rate%% [seed]]\n", argv[0]);
+	while ((opt = getopt(argc, argv, "hr:s:")) != -1) {
+		switch (opt) {
+		case 'r': // rand_rate%
+			rand_rate = atoi(optarg);
+			break;
+		case 's': // seed
+			prng_state = atol(optarg);
+			break;
+		default: // help, anything else
+			usage(0, argv[0]);
+		}
+	}
 
-	if (addr_to_ss(argv[1], &frt_addr, &err) < 0)
+	if (argc - optind < 2)
+		usage(1, argv[0]);
+
+	if (addr_to_ss(argv[optind], &frt_addr, &err) < 0)
 		die(1, "parsing listen address: %s\n", err.msg);
 
-	if (addr_to_ss(argv[2], &srv_addr, &err) < 0)
+	if (addr_to_ss(argv[optind+1], &srv_addr, &err) < 0)
 		die(1, "parsing server address: %s\n", err.msg);
 
-	if (argc > 3)
-		rand_rate = atoi(argv[3]);
-
-	if (argc > 4)
-		prng_state = atol(argv[4]);
-
 	pfd = calloc(sizeof(struct pollfd), MAXCONN + 1);
 	if (!pfd)
 		die(1, "out of memory\n");