readme(nix): Don't recommend nix-env -iA

[srid]

https://stop-using-nix-env.privatevoid.net/

[tjex]

But this is in the case that installing a package installs other dependent packages, which may overwrite (and change versions of) those packages right?

In our case, we're just installing one binary.

[worldmind]

Trying to install it:

$ nix-env -iA zk
error: attribute 'zk' in selection path 'zk' not found

although

nix run nixpkgs#zk

works, perhaps something changed

$ nix --version
nix (Nix) 2.26.3

[worldmind]

nix profile install nixpkgs#zk

works

[worldmind]

also nix profile install nixpkgs#fzf is needed for use interactive mode

[tjex]

@worldmind would you be able to consult on what the best option is for the readme? I don't have the time to understand the quirks of a new distro right now.

A PR would of course be best, or you can format it as you would here in thread in markdown and i can apply it.

[worldmind]

Sorry, but I am afraid I know nothing, I installed nix on Ubuntu just for install zk, and can't say I got what is the right way, somehow I found working way and decided to not go deeper as for now I am not sure I will use nix actively (perhaps next time I will use it via docker).
I disabled warnings:

$ cat .config/nix/nix.conf 
experimental-features = nix-command flakes

and after executing:

nix profile install nixpkgs#zk
nix profile install nixpkgs#fzf

it works.

[testplayername]

But this is in the case that installing a package installs other dependent packages, which may overwrite (and change versions of) those packages right?

In our case, we're just installing one binary.

Nix is specifically designed to avoid the problem of dependency hell. This is never an issue when using Nix.

---

Nix is a complex beast, with a package management system that looks alien compared to other package managers. A comment on a Github issue is a poor place to explain all that is Nix, so I'll try to provide a short summary of Nix here, and just the parts that are immediately relevant to this issue.

One of the primary points of Nix is declarative package management and configuration. Whereas with other package managers the way to install something would be a shell command, e.g. sudo apt install firefox and sudo pacman -S firefox, the best way to install a package in Nix is editing configuration files. This is conceptually similar to the go.mod for Go programs, but in the case of Nix, these configuration files defines a configuration of a system, including what programs are installed.

However, Nix also provides several other ways to "install" a package. This is where nix-env -iA zk and nix profile install nixpkgs#zk comes from. These two commands install the package imperatively, and I would argue both of these commands are anti-patterns, because Nix is designed for declarative package management.

Nix (and NixOS) configurations can get highly customized. Installation instructions necessarily have to assume the user has some basic Nix knowledge. I recommend these lines in the section for Nix in the readme:

---

Nix

zk is available in nixpkgs and has a Home Manager module.

If you want to run zk without permanently installing it:

nix run nixpkgs#zk

Or, if you want to create an ephemeral shell with zk available:

nix shell nixpkgs#zk

To permanently install zk on NixOS, include nixpkgs.zk in environment.systemPackages in your system configuration (/etc/nixos/configuration.nix by default).

environment.systemPackages = [
  # Your other packages here
  nixpkgs.zk
];

If you are using Home Manager, you can permanently install and configure zk just for your user via the Home Manager module. Add this to your Home Manager configuration:

programs.zk.enable = true;

[tjex]

Perfect. Thank you for the concise explanation and the text, which I think is perfect 👌

@srid , can you update the pr with the above?