--- ray/src/px/ra_avs.c	1993/10/27 09:37:37	2.5
+++ ray/src/px/ra_avs.c	1993/11/18 09:55:29	2.6
@@ -65,7 +65,7 @@ char  *argv[];
 		exit(1);
 	}
 	if (i == argc-2 && freopen(argv[i+1], "w", stdout) == NULL) {
-		fprintf(stderr, "can't open output \"%s\"\n",
+		fprintf(stderr, "%s: can't open output \"%s\"\n",
 				progname, argv[i+1]);
 		exit(1);
 	}