Start the wonderful Boris PHP REPL (https://github.com/d11wtq/boris) with Yii2. Handy for trying things out. Both files go in my home directory

.borisrc

<?php

require __DIR__ . '/startYii2.php';

$boris->setPrompt('yii2> ');

startYii2.php

<?php

// Derived from Yii2's phpunit bootstrap

// ensure we get report on all possible php errors
error_reporting(-1);

define('YII_ENABLE_ERROR_HANDLER', false);
define('YII_DEBUG', true);
$_SERVER['SCRIPT_NAME'] = '/' . __DIR__;
$_SERVER['SCRIPT_FILENAME'] = __FILE__;

$yii2dir = '/Volumes/Sites/yii2';
// require composer autoloader if available
$composerAutoload = $yii2dir . '/vendor/autoload.php';
if (is_file($composerAutoload)) {
    require_once($composerAutoload);
}
require_once($yii2dir . '/framework/Yii.php');

new \yii\console\Application([
    'id' => 'boris',
    'basePath' => __DIR__,
]);