improve help by including parent command for subcommands

command.go

@@ -39,6 +39,9 @@ type Command struct {
 	// Boolean to hide built-in help command
 	HideHelp bool
 
+	// Name of parent command for help, defaults to app.Name and parent
+	// command.Name.
+	ParentName      string
 	commandNamePath []string
 }
 
@@ -196,6 +199,7 @@ func (c Command) startApp(ctx *Context) error {
 
 	var newCmds []Command
 	for _, cc := range app.Commands {
+		cc.ParentName = app.Name
 		cc.commandNamePath = []string{c.Name, cc.Name}
 		newCmds = append(newCmds, cc)
 	}

help.go

@@ -38,10 +38,10 @@ COPYRIGHT:
 // cli.go uses text/template to render templates. You can
 // render custom help text by setting this variable.
 var CommandHelpTemplate = `NAME:
-   {{.FullName}} - {{.Usage}}
+   {{.ParentName}} {{.Name}} - {{.Usage}}
 
 USAGE:
-   command {{.FullName}}{{if .Flags}} [command options]{{end}} {{.ArgsUsage}}{{if .Description}}
+   {{.ParentName}} {{.Name}}{{if .Flags}} [command options]{{end}} {{.ArgsUsage}}{{if .Description}}
 
 DESCRIPTION:
    {{.Description}}{{end}}{{if .Flags}}