新装了Xcode之后，使用终端git的 gs（git status）命令时会出现
xcrun: error: active developer path ("/Volumes/Xcode/Xcode.app/Contents/Developer") does not exist, use xcode-select to change
解决：
It seems you had an Xcode installed in /Volumes/Xcode/Xcode.app, and then removed it.
Try executing this from a terminal:
sudo xcode-select --switch /Applications/Xcode.app然后会有一个警告提示：WARNING: Improper use of the sudo command could lead to data loss or the deletion of important system files. Please double-check your typing when using sudo. Type "man sudo" for more information.
To proceed, enter your password, or type Ctrl-C to abort.
Password:
此时输入密码，然后再gs一下就可以看到问题是否已经解决