error: selector 'bash' matches no derivations

[karelbilek]

I am absolute noob with Nix.

I am following your tutorial. I am stuck at step 6

"6. Decide what packages to install"

Well, I decided to install Bash. I do nix-env -i bash, I get

error: selector 'bash' matches no derivations

What should I do? All the tutorials I can find always assume I understand Nix :D

[karelbilek]

Also what does it mean

Review these files

darwin/casks ...

There are no files anywhere named like that?

[dustinlyons]

No worries! We were all Nix noobs at one time ;)

So on step 6, it just means you go to those files and add the packages you want. For example, I keep a bunch of stuff here:

https://github.com/dustinlyons/nixos-config/blob/main/modules/shared/packages.nix

Then when you run nixos-rebuild switch later, all those packages get installed.

You should review each file in the list from Step 6.

Finally, check this website to understand what packages are available:

https://search.nixos.org/packages

Sidenote, nix-env -i bash is an "imperative" way of installing packages. Now, with Nix, you'll just define a bunch of packages in a file and then Nix makes it so. This makes Nix "declarative", i.e describe what you want instead of running commands.

[dustinlyons]

I most always define what I want in my configuration and then let Nix install everything. But if I want to do something one-off, I run this command:

nix shell nixpkgs#<package name>

instead of nix-env.

If you see a dash in a command, that's the "legacy" way of doing Nix. If you see a space, like nix shell, that's using the latest experimental commands which will eventually become the standard way.

So I generally avoid anything with a - in it. I know, confusing.

https://nixos.org/manual/nix/stable/command-ref/experimental-commands

[karelbilek]

Ahhhh... ok... I guess? :D

After I did [ -f /etc/nix/nix.conf ] && sudo mv /etc/nix/nix.conf /etc/nix/nix.conf.before-nix-darwin

I cannot do

nix run .#build

anymore, I get

error: experimental Nix feature 'nix-command' is disabled; add '--extra-experimental-features nix-command' to enable it

Should I move it back?

So sorry for all the questions

[dustinlyons]

Just fixed the README in Step 6, you're right that was confusing. Those paths were before I did a big refactor.

Run

nix run .#build --extra-experimental-features nix-command

[dustinlyons]

Actually, pull the latest and try again. It was a bug in my command.

[dustinlyons]

Erg.. hold on. You probably used a template. I just fixed the apps/build and apps/build-switch command to use --extra-experimental-features instead of --experimental-features.

[dustinlyons]

You may have to do that in your local given your template won't update with the latest.

[dustinlyons]

Just fixed the templates as well, but you'd have to start over by initializing the template again. Or you can just fix the script like this:

https://github.com/dustinlyons/nixos-config/commit/073fac3baaccbedfa4de4c196f611f1e0d27b4f0

[karelbilek]

Thanks, now I am a bit confused what to do but will try :D

[dustinlyons]

Sorry, you're getting my responses in real time 😆

You can just grab the latest template and try again, I fixed it in the script.

Or edit the file at apps/build and apps/build-switch in your local environment to change --experimental-features to --extra-experimental-features.

Either will work.

[karelbilek]

No problem.

I.. don't have templates folder.

I just removed ~/nixos-config and started from zero. :) Hopefully.

[karelbilek]

Now I get

error: experimental Nix feature 'nix-command' is disabled; add '--extra-experimental-features nix-command' to enable it

[karelbilek]

I will try to nuke everything and start again

[karelbilek]

I got the same error.

See asciinema recording.

https://asciinema.org/a/jTfmol4P5z12bEppIOgPUNeaC (note, will get deleted in 7 days)

I will try to randomly put --extra-experimental-features nix-command to random places and see what fixes it

[karelbilek]

Why is the sudo mv /etc/nix/nix.conf /etc/nix/nix.conf.before-nix-darwin thing necessary? I think not doing it fixes things.

[karelbilek]

(and last question, should I be using these "experimental features"? According to nix manual, "Experimental features are considered unstable, which means that they can be changed or removed at any time")

[dustinlyons]

sudo mv /etc/nix/nix.conf /etc/nix/nix.conf.before-nix-darwin may not be necessary, I had a warning at one point about it but that may have gone away.

So the Nix community moves Nix forward, but they do so under 'experimental features'. They're just saying the APIs could change on you, so don't write production code on it. But the community has vastly moved on to Nix flakes, Nix commands, etc, instead of Nix channels, nix-env. It's just how the community iterates and adds new features to Nix and NixOS.

Eventually, stuff from experimental features will be stable and be part of the core.

[dustinlyons]

I wouldn't advise trying to throw --extra-experimental-features nix-command on random places :)

It just needs to be here

https://github.com/dustinlyons/nixos-config/blob/main/apps/aarch64-darwin/build https://github.com/dustinlyons/nixos-config/blob/main/apps/aarch64-darwin/build-switch

Make sure that doesn't say --experimental-features but instead it should say --extra-experimental-features.

[karelbilek]

I see that this whole repo is doing too many things at once, which is probably not for me. I try to understand 1/100 of it but it's too much. i guess it's not for newcomers to nix. Closing this issue, sorry

[dustinlyons]

Sorry this didn't work out for you. You may want to start with a few beginner-focused resources, and then once you get a grasp of the main concepts, try building your own configuration using this project as a reference.

Beginner focused resources:

• https://nixos-and-flakes.thiscute.world/

• https://zero-to-nix.com/

Best of luck!