git show-ref 查看.git存储的分支
git checkout [分支名] 定位到某个分支即可
https://blog.csdn.net/whu_zhangmin/article/details/12040493
git clone时，提示warning: remote HEAD refers to nonexistent ref, unable to checkout.
原文：https://www.cnblogs.com/CreatorKou/p/11517027.html
