--- a/src/java.base/share/classes/sun/security/tools/keytool/Main.java	Thu Jan 11 20:19:50 2018 -0800
+++ b/src/java.base/share/classes/sun/security/tools/keytool/Main.java	Tue Jan 16 08:48:34 2018 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -523,9 +523,11 @@
 
             if (c != null) {
                 command = c;
-            } else if (collator.compare(flags, "-help") == 0 ||
-                    collator.compare(flags, "-h") == 0 ||
-                    collator.compare(flags, "-?") == 0) {
+            } else if (collator.compare(flags, "--help") == 0 ||
+                       collator.compare(flags, "-h") == 0 ||
+                       collator.compare(flags, "-?") == 0 ||
+                       // -help: legacy.
+                       collator.compare(flags, "-help") == 0) {
                 help = true;
             } else if (collator.compare(flags, "-conf") == 0) {
                 i++;
@@ -4610,6 +4612,8 @@
             }
             System.err.println();
             System.err.println(rb.getString(
+                    "Use.keytool.help.for.all.available.commands"));
+            System.err.println(rb.getString(
                     "Use.keytool.command.name.help.for.usage.of.command.name"));
         }
     }