Introduction⌗

If you are using DevOS which is the official template for using digga, you may find that some friendlier commands are needed for example to rebuild your NixOS system. In this blog post, we’ll cover exactly how to do that! 😁

Implementation⌗

In your <your-config>/shell/devos.nix file, you will find a commands list, where you’re be able to add your own set of commands:

{ pkgs, extraModulesPath, inputs, lib, ... }:
...
{
  ...
  commands = [
    ...
    { # A command shipped with devos
      category = "devos";
      name = nvfetcher-bin.pname;
      help = nvfetcher-bin.meta.description;
      command = "cd $PRJ_ROOT/pkgs; ${nvfetcher-bin}/bin/nvfetcher -c ./sources.toml $@";
    }
    { # Our custom command!
      category = "devos";
      name = "switch";
      help = "Makes rebuilding easy! | usage: switch <config>";
      command = "sudo nixos-rebuild switch --flake .#$@";
    }
    ...
  ]
  ;
}

In this case, we added a switch command! We provided a name for it, a help message, as well as the command that will be executed when using switch.

After reloading the envrc using direnv reload in the command line, we get the following prompt:

[devos]

  agenix               - age-encrypted secrets for NixOS
  cachix               - Command line client for Nix binary cache hosting https://cachix.org
  deploy-rs            - A Simple multi-profile Nix-flake deploy tool
  nix                  - Powerful package manager that makes package management reliable and reproducible
  nixos-generators     - Collection of image builders
  nvfetcher            - Generate nix sources expr for the latest version of packages
  switch               - Makes rebuilding easy! | usage: switch <config>

[docs]

  mdbook               - Create books from MarkDown

[general commands]

  menu                 - prints this menu

[linter]

  editorconfig-checker - A tool to verify that your files are in harmony with your .editorconfig
  nixpkgs-fmt          - Nix code formatter for nixpkgs

The custom switch command in under the devos section/category, with the help message that we wanted.

Results⌗

And we can now rebuild and switch to a new or different version of our NixOS/DevOS config super easily 🥳!

switch <your-config>
# Instead of:
sudo nixos-rebuild switch --flake .#<your-config>