xcode.md

$> xcrun --show-sdk-path # run or locate development tools
$> xed # Xcode text editor
$> xcodebuild # build Xcode projects and workspaces
$> xcode-select # Manages the active developer directory for Xcode and BSD tools.
$> ibtool # Interface Builder tool

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/include

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk

http://osxdaily.com/2014/02/12/install-command-line-tools-mac-os-x/

https://apple.stackexchange.com/questions/337940/why-is-usr-include-missing-i-have-xcode-and-command-line-tools-installed-moja

installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /

MacOS headers: /Library/Developer/CommandLineTools/Packages