Nix journey part 0: Learning and reference materials

I think the most common use case is as a build system, but in this context you aren't limited to building packages, you can also build "environments". By "environments" I mean a shell with certain packages available in `$PATH`. You would use Nix like other build systems in the sense that you specify the build requirements (which other packages, libraries, etc you need to build _your_ stuff), then you specify how exactly to build your stuff. Here "stuff" could be as little as a shell script or as much a huge monorepo.

There are ways to use Nix like you would use Ansible or Terraform, but I wouldn't say that's the mainstream use case of Nix.

That capability turns out to be really powerful because you can materialize a program, a whole Unix tree, or even a script that converges the current host to a desired state.

I used to use Arch. I would always do a btrfs-snapshot before doing a system upgrade, then create another one after booting the new update (provided everything worked). In NixOS I don't have to because it has generations. The upgrade is entirely atomic and if it doesn't work I just use a previous generation.

Second I used to use pyenv and bunch of other tools to make sure I had the right development dependencies. Instead I just put the requirements in a shell.nix or flake.nix in the project directory, have those called with direnv. Now I can easily have python38 with clang_11 for one project and python311 with gcc48 for another.

Third the system of modules generally makes it easy to have my system setup in one place, and with the services I want. If I want zram, I just set `zramSwap.enable = true;` and that works. If I need ssh access: `services.openssh.enable = true;`, oh, but I have the firewall enabled (networking.firewall.enable = true;), that's okay because services.openssh.openFirewall defaults to true, so it handled automatically. And if I change services.openssh.ports to a better port, the firewall will be updated too.

Nix is so easy to share across machines (including Mac) that it ends up being pretty cool when you pair it with something like syncthing. I can jump around, get up to speed with something new, and have it everywhere without much setup now that my machines share some Nix code and data.

Mac support is pretty great with nix-darwin; I'm able to update my flake, run nix-build and my terminal/system level apps, Mac app store apps, homebrew apps, and dock shortcuts all get updated at once. My dock points to apps in the Nix store. Sure I could do that with some scripts, but Nix ends up being way more robust.

I also still use Emacs and the community emacs-overlay is pretty awesome.

But after you're up and running, Nix makes all this stuff generally seamless is my point. There have been times I can't update due to some upstream thing, but 80% of the time it's fixed for me in nixpkgs a few days later.

nixpkgs has like 80,000+ packages the last time I looked, and is growing.

I haven't had a use case to stray outside of Docker + terraform for my work related stuff, but it's amazing for sharing dev environments on a team. Flox is a new thing to check out

My repo if it helps anyone get started: https://github.com/dustinlyons/nixos-config