Documentation no longer correct for stable Nix

[AndrewKvalheim]

The instructions for stable now fail as in #292:

$ nix run \
  --option extra-substituters 'https://nixpkgs-update.cachix.org/' \
  --option extra-trusted-public-keys 'nixpkgs-update.cachix.org-1:6y6Z2JdoL3APdu6/+Iy8eZX2ajf09e4EE9SnxSML1W8=' \
  -f https://github.com/ryantm/nixpkgs-update/archive/main.tar.gz \
  -c nixpkgs-update --help
error: unrecognised flag '-c'
Try 'nix --help' for more information.

On stable, the instructions for unstable fail with:

$ nix shell \
  --option extra-substituters 'https://nixpkgs-update.cachix.org/' \
  --option extra-trusted-public-keys 'nixpkgs-update.cachix.org-1:6y6Z2JdoL3APdu6/+Iy8eZX2ajf09e4EE9SnxSML1W8=' \
  -f https://github.com/ryantm/nixpkgs-update/archive/main.tar.gz \
  -c nixpkgs-update --help
error: experimental Nix feature 'nix-command' is disabled; use '--extra-experimental-features nix-command' to override

nix-info

$ nix-shell --packages 'nix-info' --run 'nix-info --markdown'
 - system: `"x86_64-linux"`
 - host os: `Linux 5.15.90, NixOS, 22.11 (Raccoon), 22.11.2203.285b3ff0660`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.11.1`
 - channels(root): `"nixos-22.11, nixos-hardware"`
 - channels(user): `"home-manager-22.11.tar.gz, rust-overlay, unstable"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[gofastlily]

I'm running into this issue on a default Windows 11 install of WSL2

[nh2]

There are now 4 reasons why the install instructions don't work:

• unrecognised flag '-c'
  • What did -c even do?
• experimental Nix feature 'nix-command' is disabled
• default.nix was removed: da82da1#commitcomment-120340238
• nix run [..] nixpkgs-update --help passes --help to nix run, not to nixpkgs-update; it should be nix run [..] -- nixpkgs-update --help

[nh2]

I found a workaround, tested on commit 074e47e:

nix run:

nix --extra-experimental-features nix-command run --impure --expr 'let repo = builtins.fetchTarball https://github.com/ryantm/nixpkgs-update/archive/main.tar.gz; in import "${repo}/pkgs/" { system = "x86_64-linux"; self = repo; nixpkgs = <nixpkgs>; mmdoc = null; }' -- nixpkgs-update --help

nix shell:

nix --extra-experimental-features nix-command shell --impure --expr 'let repo = builtins.fetchTarball https://github.com/ryantm/nixpkgs-update/archive/main.tar.gz; in import "${repo}/pkgs/" { system = "x86_64-linux"; self = repo; nixpkgs = <nixpkgs>; mmdoc = null; }' nixpkgs-update

@ryantm The manual import call of my workaround doesn't look very clean. Can the default.nix in the top-level of the repo be introduced?

[eclairevoyant]

I found a workaround

It's not really a "workaround", it's just how the CLI works.
nix run -c was moved over to nix shell -c years ago.
Docs need fixing.