How to check if command line tools is installed

Question

I have a macbook pro with OS X 10.8.2. XCode is installed. I know this as it appears in the Applications directory. There are also the xcodebuild and xcode-select files in /

Answer 1

Because Xcode subsumes the CLI tools if installed first, I use the following hybrid which has been validated on 10.12 and 10.14. I expect it works on a lot of other versions:

installed=$(pkgutil --pkg-info=com.apple.pkg.CLTools_Executables 2>/dev/null || pkgutil --pkg-info=com.apple.pkg.Xcode)

Salt with awk to taste for branching logic.

Of course xcode-select -p handles the variations with a really short command but fails to give the detailed package, version, and installation date metadata.