In those early days, controlling a computer was a daunting task that could require you to manually load memory locations, one at a time, with the data that would eventually be run as a program. There are a number of different shells you can use, but if you’re wondering why anyone would want to use a shell and a command line to control a computer, you need to take a trip back in time to the dawn of the computer age. Shells are usually interactive text-based interfaces that accept commands and present the results. In this Rocket Yard guide, we’ll look at how this change to Terminal and the command line affects you.Īt the simplest level, a shell is a program that allows you to control a computer, in this case, a Mac, using commands you enter with the keyboard. The quick take away is Apple is moving from the Bash (Bourne Again Shell) to a newer Zsh. MacOS Catalina has a number of new features and capabilities, but one change that’s often overlooked is the new shell used in Terminal to interact with the Mac via the command line.