Add help template support

command_test.go

@@ -2026,8 +2026,9 @@ func TestCommand_Run_SubcommandFullPath(t *testing.T) {
 	out := &bytes.Buffer{}
 
 	subCmd := &Command{
-		Name:  "bar",
-		Usage: "does bar things",
+		Name:      "bar",
+		Usage:     "does bar things",
+		ArgsUsage: "[arguments...]",
 	}
 
 	cmd := &Command{

examples_test.go

@@ -104,6 +104,7 @@ func ExampleCommand_Run_appHelp() {
 				Aliases:     []string{"d"},
 				Usage:       "use it to see a description",
 				Description: "This is how we describe describeit the function",
+				ArgsUsage:   "[arguments...]",
 				Action: func(context.Context, *cli.Command) error {
 					fmt.Printf("i like to describe things")
 					return nil
@@ -162,6 +163,7 @@ func ExampleCommand_Run_commandHelp() {
 				Aliases:     []string{"d"},
 				Usage:       "use it to see a description",
 				Description: "This is how we describe describeit the function",
+				ArgsUsage:   "[arguments...]",
 				Action: func(context.Context, *cli.Command) error {
 					fmt.Println("i like to describe things")
 					return nil
@@ -220,6 +222,7 @@ func ExampleCommand_Run_subcommandNoAction() {
 				Name:        "describeit",
 				Aliases:     []string{"d"},
 				Usage:       "use it to see a description",
+				ArgsUsage:   "[arguments...]",
 				Description: "This is how we describe describeit the function",
 			},
 		},

help.go

@@ -377,6 +377,11 @@ func printHelpCustom(out io.Writer, templ string, data interface{}, customFuncs
 	if _, err := t.New("helpNameTemplate").Parse(helpNameTemplate); err != nil {
 		handleTemplateError(err)
 	}
+
+	if _, err := t.New("argsTemplate").Parse(argsTemplate); err != nil {
+		handleTemplateError(err)
+	}
+
 	if _, err := t.New("usageTemplate").Parse(usageTemplate); err != nil {
 		handleTemplateError(err)
 	}

template.go

@@ -1,7 +1,8 @@
 package cli
 
 var helpNameTemplate = `{{$v := offset .FullName 6}}{{wrap .FullName 3}}{{if .Usage}} - {{wrap .Usage $v}}{{end}}`
-var usageTemplate = `{{if .UsageText}}{{wrap .UsageText 3}}{{else}}{{.FullName}}{{if .VisibleFlags}} [command [command options]]{{end}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}[arguments...]{{end}}{{end}}`
+var argsTemplate = `{{if .Arguments}}{{range .Arguments}}{{.Usage}}{{end}}{{end}}`
+var usageTemplate = `{{if .UsageText}}{{wrap .UsageText 3}}{{else}}{{.FullName}}{{if .VisibleFlags}} [command [command options]]{{end}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}{{template "argsTemplate" .}}{{end}}{{end}}`
 var descriptionTemplate = `{{wrap .Description 3}}`
 var authorsTemplate = `{{with $length := len .Authors}}{{if ne 1 $length}}S{{end}}{{end}}:
    {{range $index, $author := .Authors}}{{if $index}}