A few weeks ago I ran nix flake update to get the latest versions of CLI tools that I regularly use from nixos-unstable.

atuin is one of those tools which I started using relatively recently and quickly became a huge fan of.

I run it on all of my machines, and I can’t overstate how amazing it is to have all of my shell history across all of my machines synced. I also self-host the atuin server, because why not?

While I typically install my CLI tools from nixos-unstable, with services that I self-host I tend to be a little more conservative and run them from the latest stable release, which is currenly nixos-23.11.

The atuin CLI tool had some database migrations as part of the v18 release that made it incompatible with servers running v17, which is what my self-hosted atuin server is running from nixos-23.11.

Usually this would be a non-issue since most service modules in Nixpkgs have a package option that lets you override the package used for a service. However, unfortunately for the atuin service on nixos-23.11 this is not the case (though a package override has now been added in nixos-unstable!)

As long as you have nixos-unstable as an input on your flake (hint: all my NixOS starter templates have this!) it’s possible for you to grab a single service module from nixos-unstable while keeping the rest of your services running against nixos-23.11 (or whatever the latest stable release is when you’re reading this).

}: {
  # first we need to disable the service module coming from nixpkgs
  # the path we give here is relative to the nixos/modules/ dir
  disabledModules = [

  # then we add an import of the same module from nixpkgs-unstable
  imports = [
  # now this service definition block refers to the module as defined in
  # inputs.nixos-unstable! pretty cool!
  services.atuin = {
    enable = true;
    package = pkgs.unstable.atuin;
    openRegistration = false;


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