diff --git a/Tools/autogsdoc.m b/Tools/autogsdoc.m
index 0fc49320d..edbe27510 100644
--- a/Tools/autogsdoc.m
+++ b/Tools/autogsdoc.m
@@ -855,7 +855,7 @@ standard PropertyList format (not the XML format of OS X), using
 
 	  if (![@"help" isEqual: opt])
 	    {
-	      GSPrintf(stderr, @"Unknown option:\ '%@'\n", opt);
+	      GSPrintf(stderr, @"Unknown option: '%@'\n", opt);
 	    }
 	  GSPrintf(stderr, @"Usage:\n");
 	  GSPrintf(stderr, [NSString stringWithFormat: