The program 'nix-build' is not in your PATH

gvolpe · April 8, 2024, 12:16pm

Hi all,

A bit puzzled about my NixOS system with all the nix-* commands going AWOL , not even sure where to start looking.

$ nix-build
The program 'nix-build' is not in your PATH. It is provided by several packages.
You can make it available in an ephemeral shell by typing one of the following:
....

$ nix --version
nix (Nix) 2.20.5

I’ve been messing around with flake-schemas recently, which require a specific nix version, and it seems I screwed things up. I don’t use nix-build directly, but it’s required by Home Manager, so for now I can workaround this issue by using nix shell, but it would be great to fix this properly.

I tried setting nix.package = pkgs.nixVersions.stable; # nix 2.18.1 but no luck either. This value was set to nixVersions.unstable before (nix 2.20.5), and previously to the custom nix version with schema support, and I think that’s when the problem started.

I’ve restarted my system to boot into the nix stable config as well, but commands are still gone.

Any ideas on where to start looking for a fix?

wamserma · April 8, 2024, 12:57pm

How does your $PATH look like?

Meanwhile you can access nix-build directly from the store, e.g. with `/nix/store/m28r6mf37cc8bwwq52kqdzdkc9yrq3ag-nix-2.18.1/bin/nix-build --help

gvolpe · April 8, 2024, 1:13pm

It looks as follows:

$ echo $PATH
/run/wrappers/bin /home/gvolpe/.nix-profile/bin /nix/profile/bin /home/gvolpe/.local/state/nix/profile/bin /etc/profiles/per-user/gvolpe/bin /nix/var/nix/profiles/default/bin /run/current-system/sw/bin

Yes, I can do the following, for instance:

$ nix shell nixpkgs#nix
$ which nix-build  
/nix/store/6r0bm8shswm9v08kzvq24ib48mx3kxmn-nix-2.18.1/bin/nix-build

But nix-build is needed by Home Manager, I don’t use it directly.

gvolpe · April 8, 2024, 1:17pm

Here’s something interesting from further inspecting one of the paths declared in PATH:

$ ls -la /run/current-system/sw/bin/ | rg 'nix-'
lrwxrwxrwx     - root  1 Jan  1970  nix -> /nix/store/6r0bm8shswm9v08kzvq24ib48mx3kxmn-nix-2.18.1/bin/nix
lrwxrwxrwx     - root  1 Jan  1970  nix-build -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-build
lrwxrwxrwx     - root  1 Jan  1970  nix-channel -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-channel
lrwxrwxrwx     - root  1 Jan  1970  nix-collect-garbage -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-collect-garbage
lrwxrwxrwx     - root  1 Jan  1970  nix-copy-closure -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-copy-closure
lrwxrwxrwx     - root  1 Jan  1970  nix-daemon -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-daemon
lrwxrwxrwx     - root  1 Jan  1970  nix-env -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-env
lrwxrwxrwx     - root  1 Jan  1970  nix-hash -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-hash
lrwxrwxrwx     - root  1 Jan  1970  nix-info -> /nix/store/imd120fan53pgy6qi6kra0q15v5kn6dn-nix-info/bin/nix-info
lrwxrwxrwx     - root  1 Jan  1970  nix-instantiate -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-instantiate
lrwxrwxrwx     - root  1 Jan  1970  nix-prefetch-url -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-prefetch-url
lrwxrwxrwx     - root  1 Jan  1970  nix-schema -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-schema
lrwxrwxrwx     - root  1 Jan  1970  nix-shell -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-shell
lrwxrwxrwx     - root  1 Jan  1970  nix-store -> /nix/store/cz4my09fw8ricxpan1vsr27jkva4m9z7-nix-2.21.0pre20240311_d76e5fb/bin/nix-store

All the nix-* commands are symlinked to the custom nix command with schema support. Any ideas how to fix these symlinks?

gvolpe · April 8, 2024, 1:22pm

Alright, I figured it out. I was adding nix-schema to my environment.systemPackages without noticing it’s overriding all the nix-* commands

github.com

gvolpe/nix-config/blob/54fc514170e956f50982554179b20d4ba6779f26/system/configuration.nix#L56


      
          # Select internationalisation properties.
          i18n.defaultLocale = "en_US.UTF-8";
          
          
# Set your time zone.
          time.timeZone = "Europe/Warsaw";
          
          
# List packages installed in system profile
          environment.systemPackages = with pkgs; [
            globalprotect-openconnect
            firejail
            nix-schema
            vim
            wget
          ];
          
          
# Some programs need SUID wrappers, can be configured further or are
          # started in user sessions.
          # programs.mtr.enable = true;
          programs.gnupg.agent = {
            enable = true;
            enableSSHSupport = true;