Comma runs software without installing it.

Basically it just wraps together nix shell -c and nix-index. You stick a , in front of a command to run it from whatever location it happens to occupy in nixpkgs without really thinking about it.

• Nix with Flakes:

  $ nix profile install github:nix-community/comma

• No flakes:

  $ nix-env -i -f "https://github.com/nix-community/comma/archive/master.tar.gz"

• No flakes:

  replace "v1.2.0" with the latest version

  environment.systemPackages =
  let
    comma = (import (pkgs.fetchFromGitHub {
      owner = "nix-community";
      repo = "comma";
      rev = "v1.2.0";
      sha256 = "0000000000000000000000000000000000000000000000000000";
    })).default;
  in [ comma ];

, cowsay neato

https://github.com/Mic92/nix-index-database