https://blog.gongquiz.com/2020/10/09/%eb%8b%a4%ec%9d%8c-%ec%a4%91-echo-shell-gtgt-a-txt-%eb%aa%85%eb%a0%b9%ec%9d%84-%ec%8b%a4%ed%96%89%ed%96%88%ec%9d%84-%eb%95%8c-%ea%b4%80%eb%a0%a8-%ec%84%a4%eb%aa%85%ec%9c%bc-%eb%a6%ac/