Tools You Should Know About: nix-shell
I've been aware of the Nix toolset for over a decade now, but until recently it's always looked like it required a pretty big investment. Most of the documentation I've come across explains what the benefits are and how the tooling works in order to deliver those benefits, but always from the perspective of wanting to build a project using Nix as your build system. And, well, I usually already have a build system I'm pretty happy with, and I've never bit the bullet and actually learned the pretty arcane syntax of the Nix language.
Source: Tools You Should Know About: nix-shell, an article by Gary Verhaegen.