Docker for Beginners: Complete Setup + Essential Commands Cheatsheet

Docker for Beginners: Complete Setup + Essential Commands Cheatsheet If you've heard the phrase "works on my machine" — Docker exists to kill it. It's one of those tools that sounds complicated from the outside but clicks instantly once you run your first container. This guide walks you through everything: what Docker actually is, how to install it, the concepts you need to understand, and a cheatsheet of 20+ commands you'll use every day. What Is Docker — and Why Not Just Use a VM? Docker is a platform for packaging and running applications in containers . A container bundles your app with everything it needs to run: the runtime, libraries, config files, and dependencies. You build it once, and it runs identically anywhere Docker is installed — your laptop, a teammate's machine, a CI server, or a cloud VM. The key difference from virtual machines: Virtual Machine Docker Container Includes OS kernel Yes (full OS) No (shares host kernel) Startup time Minutes Seconds Size Gigabytes Megab