# docker image
https://nixos.org/manual/nixos/stable/index.html#sec-user-management
https://hub.docker.com/r/nixos/nix
https://nixos.wiki/wiki/Cheatsheet
https://nixos.org/download.html#nix-install-docker
https://matthewrhone.dev/nixos-package-guide

docker pull nixos/nix
docker run -it nixos/nix

# list of installed packages
nix-env --query --installed

# install a package
nix-env -i <package-name>

# create nixos configuration file
/etc/nixos/configuration.nix
nix-env -i nixos-rebuild
nixos-rebuild switch

Nix configuration 
https://stackoverflow.com/questions/43169279/where-is-the-nix-configuration-located-for-the-nix-image-on-dockerhub
