How To Use WP-CLI v2 to Manage Your WordPress Site from the Command Line by Ayooluwa Isaiah (DigitalOcean)
In this tutorial, you’ll use many of the features of WP-CLI and discover how it can fit into your workflow. You’ll cover common operations such as managing plugins and themes, creating content, working with the database, and updating WordPress. The capabilities of WP-CLI go beyond this tutorial; however, you’ll be able to transfer how to work with thes more common options to other WP-CLI features.

I can’t remember if I bookmarked this at an earlier date, and I’m too lazy to look, so I’m bookmarking for when I decided to dig up the motivation to do WPCli things on this server.

UFW Essentials: Common Firewall Rules and Commands (DigitalOcean)
UFW (uncomplicated firewall) is a firewall configuration tool that runs on top of iptables, included by default within Ubuntu distributions. It provides a streamlined interface for configuring common firewall use cases via the command line. This cheat sheet-style guide provides a quick reference to common UFW use cases and commands, including examples of how to allow and block services by port, network interface, and source IP address.