http://www.liuyonghu.com/2019/08/22/%E6%9C%89%E5%A4%AA%E5%A4%9A%E4%B8%8D%E5%8F%AF%E8%BE%BE%E7%9A%84%E6%9D%BE%E6%95%A3%E5%AF%B9%E8%B1%A1-%E8%BF%90%E8%A1%8C-git-prune-%E5%88%A0%E9%99%A4%E5%AE%83%E4%BB%AC/
git gc --auto
