diff --git a/sbin/mksnap_ffs/mksnap_ffs.c b/sbin/mksnap_ffs/mksnap_ffs.c
index 1c3fb613e0aa..132843b84145 100644
--- a/sbin/mksnap_ffs/mksnap_ffs.c
+++ b/sbin/mksnap_ffs/mksnap_ffs.c
@@ -49,11 +49,13 @@
 #include <sysexits.h>
 #include <unistd.h>
 
+void usage(void);
+
 void
 usage()
 {
 
-	fprintf(stderr, "usage: mksnap_ffs mountpoint file\n");
+	fprintf(stderr, "usage: mksnap_ffs mountpoint snapshot_name\n");
 	exit(EX_USAGE);
 }