Starting with macOS Catalina, your Mac uses Zsh as the default login shell and interactive shell. Zsh provides the user with more flexibility by providing various features such as plug-in support, better customization, theme support, spelling correction, etc. The purpose of this guide is to provide an introduction to shell scripting. No prior shell script experience is required to follow along with this guide. We recommend using a non-production Mac computer when following along with the lessons in this guide.