Difference between "Get Xcode" and "Install"
Get Xcode installs both the IDE and command line developer tools.

According to apple this is the contents of that package:


  This package enables UNIX-style development via Terminal by installing command line developer tools, as well as Mac OS X SDK frameworks and headers. Many useful tools are included, such as the Apple LLVM compiler, linker, and Make. If you use Xcode, these tools are also embedded within the Xcode IDE.


Source XCode Command Line Tools - Apple Developer