Why Nix?

THIS IS A WORK IN PROGRESS ESSAY

To someone new to it, Nix may not stand out as a package manager. We’re all used to how the average package manager works. You expect it to be able to install and uninstall apps and services and then mostly get out of the way. With that in mind, you look for ease-of-use, community support, and number of packages in your package manager. These are all important in any package manager and Nix compares well in some of these metrics¹. But just looking at this, you’ll miss what makes Nix useful.

Nix isn’t just a package manager. It’s a functional programming language that just happens to also be a really good package manager. At first, it might not make sense to have a programming language just for your package manager. The Nix model of package management takes some getting used to.

Packages are represented in Nix as a special data type called a derivation. The name derivation comes from the idea that each package is derived from some inputs like source code, libraries, and build tools². Each derivation has its own directory, unique to every unique derivation written in code.

Together, these ideas make Nix really useful. To demonstrate its usefulness, I’ve outlined three points where Nix is much better than an ordinary package manager. There are many others³ but these are the ones that I think are most convincing.