You may, or may not, know that by using a Mac with macOS, you are using a system based upon the Unix operating system. When Apple acquired NeXT in 1996, it also gained the use of the NeXTSTEP operating system. NeXTSTEP had its roots in an earlier Unix system, BSD. Apple released macOS (then called Mac OS X) in 2001.
Now one of the notable things about macOS is that instead of using the traditional user interface to the operating system, NeXT had infused NeXTSTEP with a number of innovative GUI (Graphical User Interface) features which made the system far more user-friendly. For most user operations, they rarely, if ever, need to open up a Terminal and interact with the system through the command line.
This short book is for anyone who wants to open up a terminal and give commands to their system through just the keyboard. The book is only 100 pages long, so it is not an in-depth look at using the command line. It is enough to get someone started and guide them through the essentials.
You can download the free PDF at Unix for the Beginning Mage. As you might expect from the name, the book takes a bit of a tongue-in-cheek approach to learning some of the basic features of the Unix shell.
If you found this of interest you might also be interested in my CLI (Command Line Interface) page.