From b03205870bed8f8015ec3c5c03f90f5e6ce5acd1 Mon Sep 17 00:00:00 2001
From: Magnus Jacobsson <magnus.jacobsson@berotec.se>
Date: Fri, 2 Oct 2020 15:23:25 +0200
Subject: [PATCH] Show usage and exit non-zero for unsupported option in tred

Towards https://gitlab.com/graphviz/graphviz/-/issues/1843.
---
 cmd/tools/tred.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/cmd/tools/tred.c b/cmd/tools/tred.c
index a96053735..386b1f23d 100644
--- a/cmd/tools/tred.c
+++ b/cmd/tools/tred.c
@@ -259,9 +259,11 @@ static void init(int argc, char *argv[])
 	case '?':
 	    if (optopt == '?')
 		usage(0);
-	    else
-		fprintf(stderr, "%s: option -%c unrecognized - ignored\n",
+	    else {
+		fprintf(stderr, "%s: option -%c unrecognized\n",
 			CmdName, optopt);
+		usage(1);
+	    }
 	    break;
 	}
     }
-- 
2.40.0