could do some more work on the formatting, but features are complete now

GoCommando/DescriptionAttribute.cs

@@ -6,7 +6,7 @@ namespace GoCommando
     /// Apply this attribute to a property of a command class (which is also decorated with <see cref="ParameterAttribute"/>) in
     /// order to provide a description of the parameter
     /// </summary>
-    [AttributeUsage(AttributeTargets.Property)]
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Class)]
     public class DescriptionAttribute : Attribute
     {
         public string DescriptionText { get; }

GoCommando/Go.cs

@@ -81,13 +81,16 @@ static void InnerRun()
                     {
                         if (command.Parameters.Any())
                         {
-                            Console.WriteLine(@"Type
+                            Console.WriteLine(@"{0}
+
+Type
 
-    {0} {1} <args>
+    {1} {2} <args>
 
 where <args> can consist of the following parameters:
 
-{2}", 
+{3}", 
+command.Description,
 exe, 
 command.Command,
 string.Join(Environment.NewLine, command.Parameters.Select(parameter => FormatParameter(parameter, settings))));
@@ -102,13 +105,11 @@ static void InnerRun()
                         }
                         return;
                     }
-                    else
-                    {
-                        Console.WriteLine("Unknown command '{0}'", helpSwitch.Value);
-                    }
+
+                    throw new GoCommandoException($"Unknown command: '{helpSwitch.Value}'");
                 }
 
-                var availableCommands = string.Join(Environment.NewLine, commandTypes.Select(c => "    " + c.Command));
+                var availableCommands = string.Join(Environment.NewLine, commandTypes.Select(c => $"    {c.Command} - {c.Description}"));
 
                 Console.WriteLine($@"The following commands are available:
 
@@ -157,30 +158,32 @@ static string FormatParameter(Parameter parameter, Settings settings)
                 additionalProperties.Add("optional");
             }
 
-            var additionalPropertiesText = additionalProperties.Any() ? $" ({string.Join("/", additionalProperties)})" : "";
+            var additionalPropertiesText = additionalProperties.Any()
+                ? $" ({string.Join("/", additionalProperties)})"
+                : "";
 
-            var helpText = parameter.DescriptionText ?? "";
+            var helpText = "        " + (parameter.DescriptionText ?? "(no help text available)");
 
             var examplesText = !parameter.ExampleValues.Any()
                 ? ""
                 : FormatExamples(parameter, settings);
 
-            return $@"    {settings.SwitchPrefix}{parameter.Name}{shorthand}{additionalPropertiesText}
+            var switchText = $"{settings.SwitchPrefix}{parameter.Name}{shorthand}{additionalPropertiesText}";
 
+            return $@"    {switchText} 
 {helpText}
-{examplesText}
-";
+{examplesText}";
         }
 
         static string FormatExamples(Parameter parameter, Settings settings)
         {
             var examples = string.Join(Environment.NewLine, parameter.ExampleValues
-                .Select(e => $"    {settings.SwitchPrefix}{parameter.Name} {e}"));
+                .Select(e => $"          {settings.SwitchPrefix}{parameter.Name} {e}"));
 
             return $@"
-Examples:
-
-{examples}";
+        Examples:
+{examples}
+";
         }
 
         internal static List<CommandInvoker> GetCommands(Settings settings)

GoCommando/GoCommando.csproj

@@ -51,6 +51,7 @@
     <Compile Include="GoCommandoException.cs" />
     <Compile Include="Internals\Command.cs" />
     <Compile Include="Internals\Parameter.cs" />
+    <Compile Include="Internals\StringExtensions.cs" />
     <Compile Include="ParameterAttribute.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Internals\Settings.cs" />

GoCommando/Internals/Command.cs

@@ -55,6 +55,10 @@ static TAttribute GetSingleAttributeOrNull<TAttribute>(PropertyInfo p) where TAt
         public Type Type { get; }
         public IEnumerable<Parameter> Parameters { get; }
 
+        public string Description => Type.GetCustomAttribute<DescriptionAttribute>()?.DescriptionText ??
+                                     "(no help text for this command)";
+
+
         public void Invoke(IEnumerable<Switch> switches)
         {
             var commandInstance = (ICommand)Activator.CreateInstance(Type);

GoCommando/Internals/StringExtensions.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Linq;
+using System.Text;
+
+namespace GoCommando.Internals
+{
+    static class StringExtensions
+    {
+        public static string WrappedAt(this string str, int width)
+        {
+            var twoLineBreaks = Environment.NewLine + Environment.NewLine;
+
+            var sections = str.Split(new[] { twoLineBreaks },
+                StringSplitOptions.RemoveEmptyEntries);
+
+            return string.Join(twoLineBreaks, sections.Select(section => WrapSection(section, width)));
+        }
+
+        static string WrapSection(string section, int width)
+        {
+            var oneLongString = string.Join(" ",
+                section.Split(new[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries));
+
+            var words = oneLongString.Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries);
+
+            var builder = new StringBuilder();
+
+            var currentLineLength = 0;
+
+            for (var index = 0; index < words.Length; index++)
+            {
+                var word = words[index];
+                builder.Append(word);
+                currentLineLength += word.Length;
+
+                if (index < words.Length - 1)
+                {
+                    var nextWord = words[index];
+
+                    var spaceLeftOnCurrentLine = width - currentLineLength - 1; // -1 to leave room for space...
+                    var nextWordIsTooLong = nextWord.Length > spaceLeftOnCurrentLine;
+
+                    if (nextWordIsTooLong)
+                    {
+                        builder.AppendLine();
+                        currentLineLength = 0;
+                    }
+                    else
+                    {
+                        builder.Append(" ");
+                        currentLineLength++;
+                    }
+                }
+            }
+
+            return builder.ToString();
+        }
+
+        public static string Indented(this string str, int indent)
+        {
+            var indentedLines = str
+                .Split(new[] { Environment.NewLine }, StringSplitOptions.None)
+                .Select(line => string.Concat(new string(' ', indent), line));
+
+            return string.Join(Environment.NewLine, indentedLines);
+        }
+    }
+}

TestApp/Commands/RunCommand.cs

@@ -4,6 +4,7 @@
 namespace TestApp.Commands
 {
     [Command("run")]
+    [Description("Runs the program")]
     public class RunCommand : ICommand
     {
         [Description("Specifies the path with which stuff is to be done")]