The Command Line
Everything you’ve done up to this point has been inside the safe confines of the Xcode sandbox. There’s nothing wrong with that; professional programmers spend most of their time inside Xcode. But ultimately, the goal is create a “real” program that runs on its own. A program you can copy to another computer and run there. Maybe one day, a program you upload to the App Store and sell to multitudes of people around the world.
All of the projects in this book build a single executable file. A binary executable, as they are known, is the simplest form of a program that the operating system understands: a single file that contains machine code. It doesn’t get much simpler than that. When an executable is run, those ...