==> /usr/bin/sudo /bin/rm -f /tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress
==> /usr/bin/sudo /usr/bin/xcode-select --switch /Library/Developer/CommandLineTools
xcode-select: error: invalid developer directory '/Library/Developer/CommandLineTools'
Failed during: /usr/bin/sudo /usr/bin/xcode-select --switch /Library/Developer/CommandLineTools
重启Mac，按住Command + R键直到Apple Logo出现，进入Recovery Mode模式-Terminal（终端）-输入csrutil disable -重启 -
输入
sudo chflags norestricted /usr/local && sudo chown -R $(whoami):admin /usr/local
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
还是一样
==> /usr/bin/sudo /usr/bin/touch /tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress
==> Installing Command Line Tools (macOS High Sierra version 10.13) for Xcode-9.2
==> /usr/bin/sudo /usr/sbin/softwareupdate -i Command\ Line\ Tools\ (macOS\ High\ Sierra\ version\ 10.13)\ for\ Xcode-9.2
Software Update Tool
Done.
==> /usr/bin/sudo /bin/rm -f /tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress
==> /usr/bin/sudo /usr/bin/xcode-select --switch /Library/Developer/CommandLineTools
xcode-select: error: invalid developer directory '/Library/Developer/CommandLineTools'
Failed during: /usr/bin/sudo /usr/bin/xcode-select --switch /Library/Developer/CommandLineTools
注意 （仔细看）
sudo softwareupdate -i "Command Line Tools (macOS High Sierra version 10.13) for Xcode-9.2"
Software Update Tool
Downloading Command Line Tools (macOS High Sierra version 10.13) for Xcode
Done.
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/universal-darwin17/rbconfig.rb:214: warning: Insecure world writable dir /usr/local in PATH, mode 040777
brew 问题，请参见，暴力 解决 https://www.jianshu.com/p/a89d8e11cd4d