I recently tried switching from Arch to NixOS and the experience I had can best be described as apalling. I have not had a new user experience this bad since my first dip into Ubuntu dependency hell back in 2016. I'd like to preface this by saying I've been a Linux user in one form or another for almost half my life at this point, and in that time this may well be the most I've struggled to get things to work.
Apparently they have this thing called home-manager which looks pretty cool. I'd like to give that a shot. Apparently I have to enable a new Nix channel before I can install it. I'm guessing that's the equivalent of a PPA? Well, alright. nix-channel --add ..., nix-channel --update (oh, so it waits until now to tell me I typo'd the URL. Alright), and now to run the installation command and... couldn't find home-manager? Huh?? I just installed it. I google the error message and apparently you have to reboot after adding a new nix-channel and doing nix-channel --update before it will actually take effect, and the home-manager guide didn't tell me that. Ah well, at least it works now.
I didn't want to wait for KDE and its 6 morbillion dependencies to download, so I opted for Weston. It wasn't a thing in configuration.nix (programs.weston.enable=true; threw an error and there was no page for it on the NixOS wiki), but it was available in nix-env (side note: why does nix-env -i take upwards of 30 seconds just to locate a package?), so I installed it, tried to run it, and promptly got an inscrutable "Permission denied" error with one Google result that had gone unresolved. Oh well, that's alright, I guess that's not supported just yet -- I'll install Sway instead. Great, now I have a GUI and all I need is a browser. nix-env -i firefox gave me the firefox-beta binary which displayed the crash reporter before even opening a browser window. Okay, note to self: always use configuration.nix. One programs.firefox.enable=true; and one nixos-rebuild switch later, I'm off to the races. Browser is up and running. Success! Now I'd like to install a Rust development environment so I can get back to work. According to NixOS wiki, I can copy paste this incantation into a shell.nix file and have rustup in there. Cool. After resolving a few minor hangups regarding compiler version, manually telling rustc where the linker is, and telling nix-shell that I also need cmake (which was thankfully pretty easy), I'm met with a "missing pkg-config file for openssl" error that I have absolutely no idea how to begin to resolve.
I'm trying to stick with it, I really am -- I love the idea that I can just copy my entire configuration to a brand new install by copying one file and the contents of my home directory and have it be effectively the same machine -- but I'm really struggling here. Surely people wouldn't rave about NixOS as much as they do if it was really this bad? What am I doing wrong?
Also unrelated but am I correct in assuming that I cannot install KDE without also installing the X server?
I'm not sure why
nix-envis so slow exactly but it's the wrong tool to use anyways as it just throws away everything NixOS has going for itself in favour of pretending to be a normal package manager. You really just want to use the configuration file.The "normal" way to install packages in NixOS would be using
environment.systemPackages. The variousprograms.<name>options are intended for packages requiring additional setup, like shells or desktop environments (e.g. iirc for sway it creates a systemd target and adds the .desktop files for login managers to see it). Weston has a package but not an option, so you'd have to figure that additional stuff out yourself (but running Weston from a tty should just work).There are additional ways to install packages for single users or using home-manager but you don't need those.
This does kinda demonstrate why (I personally think) NixOS is so hard to learn: There's a million different ways to do anything and each has it's own weird gotchas. And critically most of them, even when they are honestly just legacy cruft, are not actually deprecated and may even have users advocating their use, or even if they don't nobody bothered to remove that part from the wiki (if it was ever there to begin with).
You can also see this in the flake/channel split: One person in this very thread is telling you to use flakes, while another is telling you to stick with the default (channels).
And in some (fortunately relatively rare) cases even things that everyone agrees are bad ideas still get promoted in official documentation or other prominent places, like using
nix-env -iunder any circumstances, ever.And it is definitely a learning problem you are having. You are facing the same problems as a new Linux user who just installed Manjaro with KDE 6 on Wayland and is wondering why
apt-getandxrandrare not working even though those are accepted answers on Stackoverflow posts from 2012. Of course as experienced Linux users we know why, but a new one has to learn a lot of stuff before "getting it" and will probably stumble onto poor advice more than once in their journey. (And learning Nix is arguably worse than learning Linux for the first time, but that depends a bit on your exact experience and background.)If you stick to learning NixOS there will be a point when these things seem trivial, but it will be a lot of effort to get there. Is that effort worth it? Well, if the term "declarative package management" doesn't mean anything to you, maybe not. You do sacrifice a lot of things "just" to declare your entire system state in one configuration file (or more likely, directory). But I do think the things Nix does are really cool, if you can get over the, uh, everything.
Also coming from Arch will induce a bit of a culture shock regarding documentation as the NixOS wiki is just... not very good. It's neither complete nor reliably accurate for the current release. And some wiki pages are actually just snippets with no explanation for either what they do or why they do it.
nix-envmust evaluate all ofnixpkgsand the reference implementation of Nix is not very fast. It's not a big mystery, although it appears that a rewrite of Nix will be required to improve it.