Add support for custom help templates.

app.go

@@ -85,6 +85,10 @@ type App struct {
 	ErrWriter io.Writer
 	// Other custom info
 	Metadata map[string]interface{}
+	// CustomAppHelpTemplate the text template for app help topic.
+	// cli.go uses text/template to render templates. You can
+	// render custom help text by setting this variable.
+	CustomAppHelpTemplate string
 
 	didSetup bool
 }

command.go

@@ -59,6 +59,11 @@ type Command struct {
 	// Full name of command for help, defaults to full command name, including parent commands.
 	HelpName        string
 	commandNamePath []string
+
+	// CustomHelpTemplate the text template for the command help topic.
+	// cli.go uses text/template to render templates. You can
+	// render custom help text by setting this variable.
+	CustomHelpTemplate string
 }
 
 type CommandsByName []Command
@@ -250,6 +255,7 @@ func (c Command) startApp(ctx *Context) error {
 
 	// set CommandNotFound
 	app.CommandNotFound = ctx.App.CommandNotFound
+	app.CustomAppHelpTemplate = c.CustomHelpTemplate
 
 	// set the flags and commands
 	app.Commands = c.Subcommands

context.go

@@ -186,9 +186,23 @@ func (a Args) First() string {
 	return a.Get(0)
 }
 
+// Last - Return the last argument, or else a blank string
+func (a Args) Last() string {
+	return a.Get(len(a) - 1)
+}
+
+// Head - Return the rest of the arguments (not the last one)
+// or else an empty string slice
+func (a Args) Head() Args {
+	if len(a) == 1 {
+		return a
+	}
+	return []string(a)[:len(a)-1]
+}
+
 // Tail returns the rest of the arguments (not the first one)
 // or else an empty string slice
-func (a Args) Tail() []string {
+func (a Args) Tail() Args {
 	if len(a) >= 2 {
 		return []string(a)[1:]
 	}

help.go

@@ -120,9 +120,19 @@ var HelpPrinter helpPrinter = printHelp
 // VersionPrinter prints the version for the App
 var VersionPrinter = printVersion
 
+// ShowAppHelpAndExit - Prints the list of subcommands for the app and exits with exit code.
+func ShowAppHelpAndExit(c *Context, exitCode int) {
+	ShowAppHelp(c)
+	os.Exit(exitCode)
+}
+
 // ShowAppHelp is an action that displays the help.
 func ShowAppHelp(c *Context) error {
-	HelpPrinter(c.App.Writer, AppHelpTemplate, c.App)
+	if c.App.CustomAppHelpTemplate != "" {
+		HelpPrinter(c.App.Writer, c.App.CustomAppHelpTemplate, c.App)
+	} else {
+		HelpPrinter(c.App.Writer, AppHelpTemplate, c.App)
+	}
 	return nil
 }
 
@@ -138,6 +148,12 @@ func DefaultAppComplete(c *Context) {
 	}
 }
 
+// ShowCommandHelpAndExit - exits with code after showing help
+func ShowCommandHelpAndExit(c *Context, command string, code int) {
+	ShowCommandHelp(c, command)
+	os.Exit(code)
+}
+
 // ShowCommandHelp prints help for the given command
 func ShowCommandHelp(ctx *Context, command string) error {
 	// show the subcommand help for a command with subcommands
@@ -148,7 +164,11 @@ func ShowCommandHelp(ctx *Context, command string) error {
 
 	for _, c := range ctx.App.Commands {
 		if c.HasName(command) {
-			HelpPrinter(ctx.App.Writer, CommandHelpTemplate, c)
+			if c.CustomHelpTemplate != "" {
+				HelpPrinter(ctx.App.Writer, c.CustomHelpTemplate, c)
+			} else {
+				HelpPrinter(ctx.App.Writer, CommandHelpTemplate, c)
+			}
 			return nil
 		}
 	}