What is the canonical way of installing Elixir or Erlang > 19 with `nix` on a non-NixOS system?

Question

Please explain it as you would to a 10-year-old, from the point after the Nix package manager is installed on a non-NixOS machine. For example, I am on a Mac, and there isn\

Answer 1

Glad I posted this question back then because the answers are terrific, but since then I realized that there is no real point in installing interpreters (especially because sometimes multiple versions are needed), so just use nix-shell on demand.

For the current version in the active channel:

nix-shell -p erlang

For other versions not in the current channel, a specific channel can be given:

nix-shell -I nixpkgs=channel:nixos-unstable -p erlangR22

Or add path to the Nix expression in your NixOS/nixpkgs clone:

$ nix-shell -I nixpkgs=~/clones/nixpkgs -p erlangR23

---

How to find packages with attribute paths on the console

$ nix-env -qaP 'erlang*'
# ...
nixos.erlangR20            erlang-20.3.8.9
nixos.erlangR21            erlang-21.3.8.3
nixos.erlang               erlang-22.1.7
# ...

$ nix-env -f ~/clones/nixpkgs/ -qaP 'erlang*'
# ...
nixos.erlangR20            erlang-20.3.8.9
nixos.erlangR21            erlang-21.3.8.3
nixos.erlang               erlang-22.1.7
# ...
=== >>> erlangR23            erlang-23.0.2  <<<====

^{This answer goes more into the details.}