In case Xcode is not installed:
$ xcrun --show-sdk-version xcrun: error: unable to read SDK settings for '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk' xcrun: error: unable to lookup item 'SDKVersion' in SDK '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk' $ xcrun --sdk macosx --show-sdk-version 12.1