# 21-nixos-configurations

This example shows a small `nixosConfigurations` output.

It includes:

- a local module in `module.nix`,
- one full system configuration exposed as `nixosConfigurations.demo`, and
- a check that reads values from the evaluated system configuration.

Useful commands:

```bash
nix flake show
nix eval .#nixosConfigurations.demo.config.networking.hostName --raw
nix flake check
```