makaihanta

А какие тогда права посоветуешь выдать директории?

Видит. Предустановленные он видеть может

кароч, вот код

/var/www/html/TestServer/wp-conten/plugins/footer-function/footer-function.php:

<?php
/*
Plugin Name: Функция Футера
Description: Добавление текста в футер
Version: 1.0.2
Author: 魔界ハンター
Text Domain: FooterFunction
*/

/*  Copyright ГОД  ИМЯ_АВТОРА_ПЛАГИНА  (email: E-MAIL_АВТОРА)

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

//Подключение ff-functions.php
require_once plugin_dir_path(__FILE__) . "includes/ff-functions.php";

/var/www/html/TestServer/wp-conten/plugins/footer-function/includes/ff-function.php:

<?php

add_action("wp_footer", "FooterFunction");

function FooterFunction()
{
    echo "ここは何かのテキストが書いてある";
}