In the pane on the left, search for 'command line tools' and choose the package appropriate to your version of OS X. Go to /downloads/index.action, and sign in with your Apple ID (the download's free). If you do not have Xcode, they are available as a separate download from Apple: To open this pane click the 'Xcode' button in the top left of the screen near the Apple logo, then click 'Preferences', then click 'Downloads'. Xcode includes a new 'Downloads' preference pane to install optional components such as command line tools, and previous iOS Simulators. Running the command in terminal produces the following GUI: Inside Xcode (5.0)

For earlier versions, continue to use the in-app download in Xcode. Or via terminal (from the release docs): The Command Line Developer Tools package can be installed on demand using ' xcode-select -install” and the installed tools will be automatically updated using Software Update. This requires signing in with a developer account.

Instead they must be downloaded from the Apple Developer Tools site. With Xcode 5.0.1 and Mavericks 10.9 the command line tool is no longer available through Xcode. 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)

Brew install xcode