Another git process seems to be running in this repository, e.g. an editor opened by ‘git commit‘.

在使用过程中，git add .之后很长时间没反应，强制关闭了git；再次打开git操作时，

提示：

“Another git process seems to be running in this repository, e.g.
an editor opened by 'git commit'. Please make sure all processes
are terminated then try again. If it still fails, a git process
may have crashed in this repository earlier:
remove the file manually to continue.”

原因：

Git在使用过程中遭遇了奔溃，部分被上锁资源没有被释放导致的。

解决方法：

直接删除 .git 文件夹内的 index.lock 文件就可以了。