diff --git a/cassh.sh b/cassh.sh
index f48ee96..37c8978 100644
--- a/cassh.sh
+++ b/cassh.sh
@@ -19,6 +19,7 @@ Usage:
 	    [-V validity_interval]
 	${0##*/} mkfile authorized_keys [options ...]
 	${0##*/} mkfile known_hosts [hostnames ...]
+	${0##*/} revoke [-qv] file ...
 EOF
 	exit 1
 }