diff --git a/stagit-index.c b/stagit-index.c
index 735775b..6402296 100644
--- a/stagit-index.c
+++ b/stagit-index.c
@@ -179,7 +179,7 @@ main(int argc, char *argv[])
 	int i, ret = 0;
 
 	if (argc < 2) {
-		fprintf(stderr, "%s [repodir...]\n", argv[0]);
+		fprintf(stderr, "usage: %s [repodir...]\n", argv[0]);
 		return 1;
 	}
 
diff --git a/stagit.c b/stagit.c
index 2a9c3fe..61c9a53 100644
--- a/stagit.c
+++ b/stagit.c
@@ -1184,7 +1184,7 @@ writerefs(FILE *fp)
 void
 usage(char *argv0)
 {
-	fprintf(stderr, "%s [-c cachefile | -l commits] "
+	fprintf(stderr, "usage: %s [-c cachefile | -l commits] "
 	        "[-u baseurl] repodir\n", argv0);
 	exit(1);
 }