diff --git a/usr.sbin/arp/arp.c b/usr.sbin/arp/arp.c
index aee3da4f4743..b0d8b8769fe4 100644
--- a/usr.sbin/arp/arp.c
+++ b/usr.sbin/arp/arp.c
@@ -627,8 +627,8 @@ usage(void)
 		"       arp [-n] [-i interface] -a",
 		"       arp -d hostname [pub]",
 		"       arp -d [-i interface] -a",
-		"       arp -s hostname ether_addr [temp] [pub]",
-		"       arp -S hostname ether_addr [temp] [pub]",
+		"       arp -s hostname ether_addr [temp] [pub [only]]",
+		"       arp -S hostname ether_addr [temp] [pub [only]]",
 		"       arp -f filename");
 	exit(1);
 }