This is a post to keep track of setting up ROS on Ubuntu 18.04LTS because the first tries made me sigh more than I wanted to.

ROS Melodic Morenia (EOL May, 2023)

ROS' Installation Guide for Ubuntu

I'm assuming you have a fresh, unmodified Ubuntu 18.04LTS install!

Repository Initializations

1. sudo apt update && sudo apt upgrade
2. Allow Ubuntu repositories "restricted," "universe," and "multiverse."
3. In the same window select "Other software" tab. Select Add, paste from below: deb http://mirror.umd.edu/packages.ros.org/ros/ubuntu bionic main This repo is hosted at the University of Maryland. The link given in ROS's guide is broken. If you want to use a different one, click below. ROS Mirrors
4. Apply/Close window. There's a good chance an error is thrown saying there's no public-key available.
5. There's a good chance a missing public key error is thrown. Open Terminal and run the command below:

   sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 5523BAEEB01FA116

It's 12:37 AM, I’m going to 🛌 😴 💤
Let the 🤖 🌚 💀 😂