public function showLog($refStart, $refEnd, $path = null, $limit = null, $offset = null, $firstParent = false)
    {
        $this->clearAll();

        $this->addCommandName(self::GIT_LOG);
        $this->addCommandArgument('-s');
        $this->addCommandArgument('--pretty=raw');
        $this->addCommandArgument('--no-color');

        if (null !== $limit) {
            $limit = (int)$limit;
            $this->addCommandArgument('--max-count=' . $limit);
        }

        if (null !== $offset) {
            $offset = (int)$offset;
            $this->addCommandArgument('--skip=' . $offset);
        }

        if (true === $firstParent) {
            $this->addCommandArgument('--first-parent');
        }

        if ($refStart instanceof TreeishInterface) {
            $refStart = $refStart->getSha();
        }

        if ($refEnd instanceof TreeishInterface) {
            $refEnd = $refEnd->getSha();
        }

        if (null !== $path && !empty($path)) {
            $this->addPath($path);
        }

        $this->addCommandSubject($refStart . '..' . $refEnd);

        return $this->getCommand();
    }