My first hurdle was configuring the network in configuration.nix. The installed template implies network settings go there, but that’s misleading. Worse, "nixos-rebuild switch" requires a working network, so a broken config leaves the system unable to fix itself – a catch-22.
Next, I tried "nix search wget", as suggested in the manual, but hit errors about missing experimental features. I had to enable both nix-command and flakes manually to get this to work:
nix --extra-experimental-features nix-command --extra-experimental-features flakes search nixpkgs wget
Even then, package search, like configuration, seems to depend on a network connection, which feels unnecessarily fragile.(edit: formatting)