laravel change Env taking app_name to next line code example

Example: laravel update env file dynamically

protected function updateDotEnv($key, $newValue, $delim='')
{

    $path = base_path('.env');
    // get old value from current env
    $oldValue = env($key);

    // was there any change?
    if ($oldValue === $newValue) {
        return;
    }

    // rewrite file content with changed data
    if (file_exists($path)) {
        // replace current value with new value 
        file_put_contents(
            $path, str_replace(
                $key.'='.$delim.$oldValue.$delim, 
                $key.'='.$delim.$newValue.$delim, 
                file_get_contents($path)
            )
        );
    }
}