Hacking the Mainframe: Getting Acquaintedīefore we get started, let’s talk about the working directory. If Terminal is brand new for you, start here. Once you know how to launch Terminal and input commands, you can come back here to expand your knowledge. This can make learning Terminal tricky, and not a little bit daunting. Fortunately there’s nothing to be anxious about: great power is at your fingertips, and you need only learn the right macOS Terminal commands. But while it gives users more power, it also ditches the graphical interface we all know and love. Terminal, sometimes called the command line interface or CLI, is a text-based program for interacting with your computer’s deepest levels.