error: file 'nixpkgs' was not found in the Nix search path (add it using $NIX_PATH or -I) about nixos-bpir3-example HOT 2 CLOSED

Which is presumably because the NIX_PATH environment variable is not set.

I don't think these paths would be checked if the environment variable was not set.
It looks like they're set by PAM from /etc/pam/environment

Do you know how that could be fixed?

It looks like the channel is defined

[root@bpir3:~]# nix-channel --list
nixos https://nixos.org/channels/nixos-unstable

After I run the following it populates

[root@bpir3:~]# nix-info 
system: "aarch64-linux", multi-user?: no, version: nix-env (Nix) 2.13.3, nixpkgs: not found

[root@bpir3:~]# nix-channel --update
unpacking channels...

[root@bpir3:~]# nix-info 
system: "aarch64-linux", multi-user?: yes, version: nix-env (Nix) 2.13.3, channels(root): "nixos", nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos

Looking into it, it looks like it's normally pre-populated on "installation media" via <nixpkgs>/nixos/modules/installer/cd-dvd/channel.nix.
It's not very obvious, but it looks like that is intended to be included in "golden images" as well, and it takes care of doing a one-time command at boot to set it up to a copy of nixpkgs in the nix-store included in the filesystem.

This was an interesting one, it looks like I never ran into this one because I manage the device entirely via nix-command (nix shell instead of nix-shell) and flakes, and my in-service router still doesn't have those channel links.

from nixos-bpir3-example.

Thanks for the explanation, updating channel information fixed the issue 👍

from nixos-bpir3-example.