1 files changed, 38 insertions, 5 deletions

diff --git a/src/WixToolset.Core/CommandLine/HelpCommand.cs b/src/WixToolset.Core/CommandLine/HelpCommand.cs
index 78845189..3af442aa 100644
--- a/src/WixToolset.Core/CommandLine/HelpCommand.cs
+++ b/src/WixToolset.Core/CommandLine/HelpCommand.cs
@@ -3,27 +3,60 @@
 namespace WixToolset.Core.CommandLine
 {
     using System;
+    using System.Collections.Generic;
+    using System.Linq;
     using System.Threading;
     using System.Threading.Tasks;
+    using WixToolset.Extensibility;
     using WixToolset.Extensibility.Data;
     using WixToolset.Extensibility.Services;
 
     internal class HelpCommand : ICommandLineCommand
     {
+        private static readonly ExtensionCommandLineSwitch[] BuiltInSwitches = new ExtensionCommandLineSwitch[]
+        {
+            new ExtensionCommandLineSwitch { Switch = "build", Description = "Build a wixlib, package or bundle." },
+            new ExtensionCommandLineSwitch { Switch = "decompile", Description = "Decompile a package or bundle into source code." },
+        };
+
+        public HelpCommand(IEnumerable<IExtensionCommandLine> extensions)
+        {
+            this.Extensions = extensions;
+        }
+
         public bool ShowLogo => true;
 
         public bool StopParsing => true;
 
+        private IEnumerable<IExtensionCommandLine> Extensions { get; }
+
         public Task<int> ExecuteAsync(CancellationToken _)
         {
-            Console.WriteLine("TODO: Show list of available commands");
+            var commandLineSwitches = new List<ExtensionCommandLineSwitch>(BuiltInSwitches);
+            commandLineSwitches.AddRange(this.Extensions.SelectMany(e => e.CommandLineSwitches).OrderBy(s => s.Switch, StringComparer.Ordinal));
+
+            Console.WriteLine();
+            Console.WriteLine("Usage: wix [option]");
+            Console.WriteLine("Usage: wix [command]");
+            Console.WriteLine();
+            Console.WriteLine("Options:");
+            Console.WriteLine("  -h|--help         Show command line help.");
+            Console.WriteLine("  --version         Display WiX Toolset version in use.");
+            Console.WriteLine();
+
+            Console.WriteLine("Commands:");
+            foreach (var commandLineSwitch in commandLineSwitches)
+            {
+                Console.WriteLine("  {0,-17} {1}", commandLineSwitch.Switch, commandLineSwitch.Description);
+            }
+
+            Console.WriteLine();
+            Console.WriteLine("Run 'wix [command] --help' for more information on a command.");
+            AppCommon.DisplayToolFooter();
 
             return Task.FromResult(-1);
         }
 
-        public bool TryParseArgument(ICommandLineParser parseHelper, string argument)
-        {
-            return true; // eat any arguments
-        }
+        public bool TryParseArgument(ICommandLineParser parseHelper, string argument) => true; // eat any arguments
     }
 }