Well, there is "nix-env -i -f /etc/nixos/nixpkgs -A ... " (if you add to all-packages.nix). Read manual for details and shorter invocations. You can also use "nix-build ... -o result" and use result/bin/.. . You can also add packages mentioned in all-packages.nix to environment.extraPackages in configuration.nix . You can also use "nix-env -i /nix/store/path".