This course is a concise crash-course into Linux Shell. Although it is short, it introduces you to several commands to interact with files and directories and build a chain of commands into pipelines: ls, cp, chmod, grep, find, less, head, and even more. Whether you are in an urgent need to get familiar with common shell commands or want to take your time and discover a command-line interface, this course will help you to get started.
What is Command Line Interface (CLI, or just Shell)? Wikipedia says it is "a means of interacting with a computer program where the user (or client) issues commands to the program in the form of successive lines of text (command lines). A program which handles the interface is called a command language interpreter or shell (computing)". Command-Line gives you great control over functions of the operating system, as well as the hardware of your computers, such as a network or a sound card. Many end-user applications have a user interface that simplifies the user experience, and if you want better flexibility, the Command-Line gives you this option.
Command Line Interface is the core of the operating system, it gives you access to the lowest level of interactions with it. This course will focus on the Linux/Unix interface, but most of the commands in the course are also available in macOS.
You should have Linux, e.g. Ubuntu, installed on your computer. A Linux running on a virtual machine, e.g. VirtualBox, would also work.