Questions about nix-info and flakes setup

By looking at the output of nix-info, I noticed a few things which I didn’t know how to interpret:

❯ nix-info -m
 - system: `"x86_64-linux"`
 - host os: `Linux 5.10.79, NixOS, 21.11 (Porcupine)`
 - multi-user?: `yes`
 - sandbox: `no`
 - version: `nix-env (Nix) 2.4`
 - channels(root): `"nixos-21.05.650.eaba7870ffc"`
 - channels(asymmetric): `""`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`


Why is sandbox off? I don’t change the default value (which is true):

❯ nixos-option -I nixos-config=/home/asymmetric/code/dotfiles/configuration.nix nix.useSandbox


# ...

appending to nix.nixPath

How would I go about changing the value of nixos-config in NIX_PATH, so that I don’t have to pass that -I flag above?

I would like to append/merge to the existing values, something like:

# flake.nix

nix = rec {
  nixPath = nixPath ++ [ "nixos-config=/home/asymmetric/code/dotfiles/configuration.nix" ];

but this (obviously?) triggers infinite recursion.


If I exclusively use flakes and the new experimental nix command, should I still care about channels? If not, can I simply delete the directory?

If I should still care, how can I ensure they are kept up to date with the version of nixpkgs in my flake?