If you're a developer of multiple projects, you'll find yourself needing to switch between multiple different version control systems. After working in one (e.g. SVN) for an hour, you may need to switch to a different one (e.g. git). Getting your fingers to switch is the difficult part, or remembering the right command line flags to use for the given tool. That's where The One Ring comes in: it provides a constant interface to all the version control systems, and your fingers only need to remember a single command regardless of what checkout directory your shell is sitting in.
