The solution is to download directly, see 'Separate Download' below. In late February 2014 the command started only displaying help. In early February 2014 xcode-select -install has been reporting that 'Can't install the software because it is not currently available from the Software Update server'. So, try xcode-select -install and if that does not work download as described below.
Xcode-select -install worked with version 2333, failed with version 2003. (also works with Xcode 5.1.1 + OSX 10.10)
