public function set($key, $value, $linebreak = false)
    {
        $oldValue = $this->get($key);

        if (! preg_match('/\d/', $value) || preg_match('/=/', $value)) {
            $value = "\"$value\"";
        }

        $new = $linebreak ? "\n$key=$value" : "$key=$value";

        if (! is_null($oldValue)) {
            return $this->replaceInFile("$key=$oldValue", $new);
        }

        file_put_contents($this->getPath(), "\n$new", FILE_APPEND);

        return $this;
    }