Why can't I call my command in the Yii2 console?

Question

Yii

There is a basic application yii2.
I created a copy of the HelloController.php controller in the /basic/commands/ folder but named it differently (both the file name and directly in the code), but it gives an error Error: Unknown command "xls".
What should I do so that the application sees my commands?
Controller code

<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace app\commands;

use yii\console\Controller;

/**
 * This command echoes the first argument that you have entered.
 *
 * This command is provided as an example for you to learn how to create console commands.
 *
 * @author Qiang Xue <[e-mail]>
 * @since 2.0
 */
class XlsController extends Controller
{
    /**
     * This command echoes what you have entered as the message.
     * @param string $message the message to be echoed.
     */
    public function actionIndex($message = 'hello world')
    {
        echo $message . "\n";
    }
}

The contents of the folder /opt/lampp/htdocs/basic/commands/
HelloController.php and XlsController.php
I invoke the following command
***@********:/opt/lampp/htdocs/basic$ php yii xls
Error: Unknown command "xls".

Answer 1

Drive in the command
And you will understand everything.