~ $ nix-shell -p nix-info --run nix-info
these paths will be fetched (0.32 MiB download, 1.90 MiB unpacked):
  /nix/store/9iwglb4s17wyry7avixiffglhpvqwv39-bash-4.4-p12-doc
  /nix/store/n50nxcgvx20bfyyfn9m7nzkjwzccbbai-bash-4.4-p12-dev
copying path '/nix/store/9iwglb4s17wyry7avixiffglhpvqwv39-bash-4.4-p12-doc' from 'https://cache.nixos.org'...
copying path '/nix/store/n50nxcgvx20bfyyfn9m7nzkjwzccbbai-bash-4.4-p12-dev' from 'https://cache.nixos.org'...
system: "x86_64-linux", multi-user?: yes, version: nix-env (Nix) 2.0.4, channels(root): "nixos-18.03.132915.d6c6c7fcec6", channels(matt): "nixos-18.09pre145679.dae9cf6106d", nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs