--- ray/src/px/ra_skel.c	1993/10/27 09:37:35	2.7
+++ ray/src/px/ra_skel.c	1993/11/18 09:55:24	2.8
@@ -74,7 +74,7 @@ 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);
 	}