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 /
On macOS Sierra (10.12) :
Run the following command to see if CLT is installed:
xcode-select -p
this will return the path to the tool if CLT is already installed. Something like this -
/Applications/Xcode.app/Contents/Developer
Run the following command to see the version of CLT:
pkgutil --pkg-info=com.apple.pkg.CLTools_Executables
this will return version info, output will be something like this -
package-id: com.apple.pkg.CLTools_Executables
version: 8.2.0.0.1.1480973914
volume: /
location: /
install-time: 1486372375