❯ nixos-rebuild build --flake
❯ echo $?
1
# no idea what happened, but it wasn't good

❯ nixos-rebuild build --flake .                               
building the system configuration...
error: --- Error --------------------------------------------------------------------------------------------------------- nix
flake 'git+file:///home/cole/code/nixos-flake-example?ref=master&rev=72f39dbc313b395437e892f722d270a50e9c995b' does not provide attribute 'packages.x86_64-linux.nixosConfigurations."slynux".config.system.build.toplevel', 'legacyPackages.x86_64-linux.nixosConfigurations."slynux".config.system.build.toplevel' or 'nixosConfigurations."slynux".config.system.build.toplevel'