https://computingforgeeks.com/virsh-commands-cheatsheet/

vim /mnt/etc/nixos/configuration.nix
    # boot.loader.grub.device = "/dev/sda";
    # at hardware-configuration.nix
        swapDevices = [ device = "/.swapfile"; ]

nixos-install
reboot
sudo poweroff
shutdown -h now

packages
    nix-env -q --installed
    nix-env -qaP \*

    nix-env -iA nixos.gitMinimal nixos.gh
    nix-env -iA nixos.git nixos.gh

    nix-env -iA nixos.gitMinimal

    nix-env -iA nixos.pkgs.gitAndTools.gitFull
    nix-env -iA nixos.gitAndTools.gh

gh
https://cli.github.com/manual/gh_auth_login
https://cli.github.com/manual/gh_repo_clone
    export GH_TOKEN=...
    gh auth login
    gh repo clone iharh/nixcfg

cache
https://nixos.wiki/wiki/Maintainers:Fastly
https://www.channable.com/tech/setting-up-a-private-nix-cache-for-fun-and-profit
https://mcwhirter.com.au/craige/blog/2019/NixOS%5FAppears%5Fto%5Fbe%5FAlways%5FBuilding%5FFrom%5FSource/

users.user.iharh = {
    initialPassword = "pwd";
    isNormalUser = true;
    extraGroups = [ "wheel" ];
};