PHP wp-config file for multiple wordpress environments.

wp-config.multi.php

<?php
$current_config = __DIR__ . '/' . $_SERVER['HTTP_HOST'] . '.config.php';
if (file_exists($current_config))
    require_once $current_config;
else {
    
    /**
     * The base configurations of the WordPress.
     *
     * This file has the following configurations: MySQL settings, Table Prefix,
     * Secret Keys, WordPress Language, and ABSPATH. You can find more information
     * by visiting {@link http://codex.wordpress.org/Editing_wp-config.php Editing
     * wp-config.php} Codex page. You can get the MySQL settings from your web host.
     *
     * This file is used by the wp-config.php creation script during the
     * installation. You don't have to use the web site, you can just copy this file
     * to "wp-config.php" and fill in the values.
     *
     * @package WordPress
     */

    // ** MySQL settings - You can get this info from your web host ** //
    /** The name of the database for WordPress */
    define('DB_NAME', 'db');

    /** MySQL database username */
    define('DB_USER', 'user');

    /** MySQL database password */
    define('DB_PASSWORD', 'pass');

    /** MySQL hostname */
    define('DB_HOST', 'localhost');

    /** Database Charset to use in creating database tables. */
    define('DB_CHARSET', 'utf8');

    /** The Database Collate type. Don't change this if in doubt. */
    define('DB_COLLATE', '');

    /**#@+
     * Authentication Unique Keys and Salts.
     *
     * Change these to different unique phrases!
     * You can generate these using the {@link https://api.wordpress.org/secret-key/1.1/salt/ WordPress.org secret-key service}
     * You can change these at any point in time to invalidate all existing cookies. This will force all users to have to log in again.
     *
     * @since 2.6.0
     */
    define('AUTH_KEY',         'Jv{-db;bcpcP,wSqxxX8&~,K2R-AOs*GJ.xl8q<>Rv+f+ir-!}uJ!=<mSPU6eGP-');
    define('SECURE_AUTH_KEY',  'qK~-TMz_w0%Qr>I#1N kKSxA{;5;@*le8!/]Yv[-IE3@kW&)$~k+<exM@]kZZy-c');
    define('LOGGED_IN_KEY',    '.+`i9`9~N)9DYa.b:#|pb#s:}rKhsYJ.S-gMjm@$LU>=n5Jjw=1Iu],1i|ST)&%U');
    define('NONCE_KEY',        '}40j`h)z6O:~Yu|fvG&#H&|c-$Y+_.lAW{L#<?.1#mD$rc@9$q3F@3H+MKeo|R4e');
    define('AUTH_SALT',        'K@,Uc*oJr36`+*IaHW;sDyhy{##o5NH%4|PXt_f9&-Da R%bTd?]cn}%xC+eAQR/');
    define('SECURE_AUTH_SALT', ':?+2IRvVX!V(A6h5[h#3d0!/t|q+Z+hg|MF0.=%s[<@)j.ed#$7C%Nay=>WWi`M3');
    define('LOGGED_IN_SALT',   'h(:_#1<O$PT+2q~r%)PU.IeKA:0%90BZ|a%uEC)f{@;-]f]E+d+Pa=q@z~PWd(pg');
    define('NONCE_SALT',       'C nO[Z]pHM-^BbQdr=.Hwl2rTP25hs4#d@3?Qz!A&}nwwUL*Uq-PL|M6>e|{+)Vv');

    /**#@-*/

    /**
     * WordPress Database Table prefix.
     *
     * You can have multiple installations in one database if you give each a unique
     * prefix. Only numbers, letters, and underscores please!
     */
    $table_prefix  = 'wp_';

    /**
     * WordPress Localized Language, defaults to English.
     *
     * Change this to localize WordPress. A corresponding MO file for the chosen
     * language must be installed to wp-content/languages. For example, install
     * de_DE.mo to wp-content/languages and set WPLANG to 'de_DE' to enable German
     * language support.
     */
    define('WPLANG', '');

    /**
     * For developers: WordPress debugging mode.
     *
     * Change this to true to enable the display of notices during development.
     * It is strongly recommended that plugin and theme developers use WP_DEBUG
     * in their development environments.
     */
    define('WP_DEBUG', false);

    /* That's all, stop editing! Happy blogging. */

    /** Absolute path to the WordPress directory. */
    if ( !defined('ABSPATH') )
        define('ABSPATH', dirname(__FILE__) . '/');

    /** Sets up WordPress vars and included files. */
    require_once(ABSPATH . 'wp-settings.php');

}