最近想要更新 Mac 上的 Homebrew 時，
突然出現 Git must be installed and in your PATH! 的錯誤訊息：
testuser@localhost ~ $ brew update Warning: git 2.15.1 is already installed Error: Git must be installed and in your PATH!
這真是莫名其妙，我的 git 裝的好好的，也可以正常執行…
跑跑看 brew doctor 檢測一下：
testuser@localhost ~ $ brew doctor Please note that these warnings are just used to help the Homebrew maintainers with debugging if you file an issue. If everything you use Homebrew for is working fine: please don't worry or file an issue; just ignore this. Thanks! Warning: Git could not be found in your PATH. Homebrew uses Git for several internal functions, and some formulae use Git checkouts instead of stable tarballs. You may want to install Git: brew install git Warning: No developer tools installed. Install the Command Line Tools: xcode-select --install
訊息的前半部叫我要裝 git => 但我早就裝了
訊息的後半部比較有參考價值 => 叫我要安裝 xcode 的命令列工具～
猜測應該是因為最近 xcode 有更新的關係…
就照著指令安裝 xcode 命令列工具吧：
testuser@localhost ~ $ xcode-select --install xcode-select: note: install requested for command line developer tools
testuser@localhost ~ $ brew doctor Your system is ready to brew.