diff --git a/lldb/source/Commands/CommandObjectHelp.cpp b/lldb/source/Commands/CommandObjectHelp.cpp
index f73d9d2..f6fd9f6 100644
--- a/lldb/source/Commands/CommandObjectHelp.cpp
+++ b/lldb/source/Commands/CommandObjectHelp.cpp
@@ -54,9 +54,10 @@
 OptionDefinition
 CommandObjectHelp::CommandOptions::g_option_table[] =
 {
-    { LLDB_OPT_SET_ALL, false, "show-aliases", 'a', OptionParser::eNoArgument, NULL, NULL, 0, eArgTypeNone,         "Show aliases in the command list."},
+    { LLDB_OPT_SET_ALL, false, "hide-aliases", 'a', OptionParser::eNoArgument, NULL, NULL, 0, eArgTypeNone,         "Hide aliases in the command list."},
     { LLDB_OPT_SET_ALL, false, "hide-user-commands", 'u', OptionParser::eNoArgument, NULL, NULL, 0, eArgTypeNone,         "Hide user-defined commands from the list."},
-    { 0, false, NULL, 0, 0, NULL, NULL, 0, eArgTypeNone, NULL }
+    { LLDB_OPT_SET_ALL, false, "show-hidden-commands", 'h', OptionParser::eNoArgument, NULL, NULL, 0, eArgTypeNone,         "Include commands prefixed with an underscore."},
+    { 0, false, NULL, NULL, 0, 0, NULL, 0, eArgTypeNone, NULL }
 };
 
 bool
@@ -75,6 +76,8 @@
             cmd_types |= CommandInterpreter::eCommandTypesAliases;
         if (m_options.m_show_user_defined)
             cmd_types |= CommandInterpreter::eCommandTypesUserDef;
+        if (m_options.m_show_hidden)
+            cmd_types |= CommandInterpreter::eCommandTypesHidden;
 
         result.SetStatus (eReturnStatusSuccessFinishNoResult);
         m_interpreter.GetHelp (result, cmd_types);  // General help
@@ -136,17 +139,19 @@
                 else if (!sub_cmd_obj)
                 {
                     result.AppendErrorWithFormat("'%s' is not a known command.\n"
-                                                 "Try 'help' to see a current list of commands.\n",
-                                                 cmd_string.c_str());
+                                                 "Try '%shelp' to see a current list of commands.\n",
+                                                 cmd_string.c_str(),
+                                                 m_interpreter.GetCommandPrefix());
                     result.SetStatus (eReturnStatusFailed);
                     return false;
                 }
                 else
                 {
                     result.GetOutputStream().Printf("'%s' is not a known command.\n"
-                                                   "Try 'help' to see a current list of commands.\n"
+                                                   "Try '%shelp' to see a current list of commands.\n"
                                                     "The closest match is '%s'. Help on it follows.\n\n",
                                                    cmd_string.c_str(),
+                                                   m_interpreter.GetCommandPrefix(),
                                                    sub_cmd_obj->GetCommandName());
                 }
             }
@@ -183,8 +188,9 @@
             else
             {
                 result.AppendErrorWithFormat 
-                    ("'%s' is not a known command.\nTry 'help' to see a current list of commands.\n",
-                     command.GetArgumentAtIndex(0));
+                    ("'%s' is not a known command.\nTry '%shelp' to see a current list of commands.\n",
+                     command.GetArgumentAtIndex(0),
+                     m_interpreter.GetCommandPrefix());
                 result.SetStatus (eReturnStatusFailed);
             }
         }