Hello World program of WP CLI (WordPress Command Line Interface)

wp-cli-hello-world.php

<?php
/**
 * Common API's: WP CLI
 *
 * 1. Run `wp examples hello_world`     Simple Command.
 * 
 * @package wordpress-examples
 * @since 1.0.0
 */

if ( ! class_exists( 'WordPress_Examples_WP_CLI' ) && class_exists( 'WP_CLI_Command' ) ) :

	/**
	 * WordPress Examples
	 */
	class WordPress_Examples_WP_CLI extends WP_CLI_Command {

		/**
		 * hello_world
		 *
		 * ## EXAMPLES
		 *
		 *     # Simple Command
		 *     $ wp examples hello_world
		 *     ok
		 *
		 * @since 1.0.0
		 * @param  array $args        Arguments.
		 * @param  array $assoc_args Associated Arguments.
		 *
		 * @alias list
		 */
		public function hello_world( $args, $assoc_args ) {
			// Code Goes Here..
		}
	}

	/**
	 * Add Command
	 */
	WP_CLI::add_command( 'examples', 'WordPress_Examples_WP_CLI' );

endif;