有時候在提交的時候，中間提交出錯，導致有文件被lock，所以會報下面的錯誤：
fatal: Unable to create ‘/msg/.git/index.lock’: File exists.
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.
出現這種情況可以用以下解決辦法：
試着刪除 index.lock
1、命令行代碼 rm -f ./msg/.git/index.lock
2、直接去文件系統進行刪除該lock文件