Reorganise the Package Management chapter

[fricklerhandwerk]

Problem

The Package Management chapter is a mix of explanations, tutorials, and guides, most of which refer to nix-env, which is well-known to behave surprisingly. Since this is the first thing encountered by many users looking for instructions on how to use Nix (rightly so, since this is authoritative documentation), beginners are thrown for a long loop of not following best practices and end up with having to re-do lots of work or giving up in frustration.

Additionally, we agreed to move towards a structure of documentation following the Diátaxis framework, and that this manual should be a reference, which is reflected in its title.

Related:

• https://stop-using-nix-env.privatevoid.net/
• https://discourse.nixos.org/t/depreciate-the-use-of-nix-env-to-install-packages/20139

Proposal

Remove the entire Package Management chapter from the manual.

The parts on garbage collection and channels are documented well enough in the respective command pages and can be removed, too. The parts on serving the Nix store could either be moved to a dedicated cookbook such as nix.dev or accommodated as examples for the substituters setting in nix.conf documentation.

This needs a bit of care not to lose vital information for beginners, and may be carried out in multiple steps.

TODO

• [x] #7972
• [ ] NixOS/nix.dev#460
• [x] #7973
• [x] #7974
• [ ] #7976
• [ ] #7977
• [ ] NixOS/nix.dev#461
• [ ] #7978
• [x] https://github.com/NixOS/nix.dev/issues/463
• [ ] Move "Serving Nix Store via HTTP" to nix.dev
  • Related: https://github.com/NixOS/nix/pull/8256

Checklist

• [x] checked latest Nix manual (source)
• [x] checked open documentation issues and pull requests for possible duplicates

Priorities

Add :+1: to issues you find important.

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/tweag-nix-dev-update-45/26397/1

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/2023-03-31-nix-team-meeting-minutes-45/27002/1

[fricklerhandwerk]

Discussed in the Nix team meeting 2023-04-03:

• @ericson2314: two things going on:
  • nix-env seems to be overemphasized (opinions, controversial)
  • making the manual pure reference documentation (not controversial)
• @thufschmitt: nothing against it as long as no information is lost
  • @edolstra: agreed. it should just not sound like nix-env should not be used
    • @fricklerhandwerk: yes, the goal of the reference manual is just stating what's there
  • @ericson2314: posts should show up on nix.dev first before deleting them from the manual
    • we may want to consider managing redirects in the Nix repo instead of on nixos-homepage
• idea approved

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/2023-04-03-nix-team-meeting-minutes-46/27008/1

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/2023-04-06-documentation-team-meeting-notes-39/27048/1

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/2023-06-01-documentation-team-meeting-notes-51/28635/1

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/how-to-upgrade-packages/6151/16