• https://github.com/nix-community/emacs-overlay
• pre-commit
• asdf-vm
• fn

To install the overlay into ~/.config/nixpkgs/overlays just run:

./install.sh

now you can test your builds using:

nix-shell -p <package>

add the following to your /etc/nixos/configuration.nix:

nixpkgs.config.packageOverrides = import /path/to/overlay.nix pkgs;

now you can install the packages from the overlay

environment.systemPackages = with pkgs; [
    <package>
];

nix-build -E 'with import <nixpkgs> {} ; callPackage ./default.nix {}';

should create a ./result folder which contains the result of the package.

nix-shell -p nix-prefetch --run "nix-prefetch fetchurl --urls --expr '[ <file download url> ]'"

• mrVanDalo/nix-overlay (Where this README modified from)
• A presentation about Overlays
• Package Binaries