You've mastered the command line. You understand your operating system and your development environment. Now it's time to learn how modern developers leverage the work of others: through packages, registries, and package managers.
Everything that comes next—Claude Code, Docker, OpenClaw, web applications—builds on the concepts you're about to learn. And at the center of all of it is a simple idea: reusable code, stored in a central place, installed with a single command. This is where we leverage the power of the Internet and begin to see the open-source community come into play.
Let's start with the why, then move to the how.
What is a Package?
A package (also called a module or library) is a collection of reusable code that someone else wrote, tested, and shared. Instead of writing authentication from scratch, you install a package that handles it. Instead of building a web server from the ground up, you install a package that does it for you.
