There is also https://nixery.dev/ which lets you get Docker images with arbitrary Nix packages - useful for quick hacking.

Kind of confusing. NixOS vs Nix the language...

You use Nix the language to build Docker images and avoid the NixOS CLI tools/runtime?

Nix the package manager.

Nix the language.

NixOS the Linux built with Nix as it's default package manager that uses the Nix language.

Nix the language can compile OCI (Open Container Initiative) format images that can be deployed/ran/executed via Docker or k8s?

Or is that Nix the package manager? Does Nix the package manager compile Nix the language images?

[nixpkgs the package collection] (which is used by [Nix the package manager], and also contains the [Nix the programming language] expressions that define [NixOS the operating system]) has expressions for easily building OCI images: https://nixos.org/manual/nixpkgs/stable/#sec-pkgs-dockerTool...

Do you have to be on NixOS to use the OCI images outputtable by nixpks/nix package manager or can you build OCI images using Nix from Mac/Windows/other non NixOS Linux?

> Do you have to be on NixOS to use the OCI images outputtable by nixpks/nix package manager

No

> can you build OCI images using Nix from Mac/Windows/other non NixOS Linux?

Non NixOS Unix, not Windows yet, unless you use WSL or a VM

They're just normal OCI images, so they can be run by any OCI-compatible container runtime. You can build images from any system running Nix, though you might encounter trouble on non-Linux systems because you may need to cross-compile the packages you use. The build process is exactly the same on any Linux distro (including NixOS and anything else) though.

woah - this is great, thanks