If no other git process is currently running, this probably means a git process crashed in this repo

在使用git时候出现如下问题：

vmuser@Linux-host:rootfs$ git add dev/
fatal: Unable to create '/home/vmuser/tiny4412/.git/index.lock': ?????.

If no other git process is currently running, this probably means a
git process crashed in this repository earlier. Make sure no other git
process is running and remove the file manually to continue.
vmuser@Linux-host:rootfs$ ls dev/

解决方法：

rm -f ./.git/index.lock