experimental nix

scripts/deploy

@@ -81,6 +81,17 @@ REPO="$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null || dirname "$
 cd "$REPO"
 export PATH="/nix/var/nix/profiles/default/bin:$PATH"
 
+# Every `nix` call below assumes `nix-command` + `flakes`. Those are ambient on
+# a Determinate-Nix laptop, but a STOCK NixOS box leaves both experimental
+# features OFF — so bare `nix eval`/`build`/`run` die with "experimental Nix
+# feature 'nix-command' is disabled". That box is exactly the prepare host for
+# `install <config> localhost` (a fresh NixOS the reinstall runs from), and it
+# is why the installer-iso already sets these itself (flake.nix). Enable them
+# additively via NIX_CONFIG (extra-, so anything already configured is kept).
+# This runs again at the top of the sudo re-exec in require_root(), so root
+# gets it too regardless of whether `sudo -E` carries the env across.
+export NIX_CONFIG="$(printf 'extra-experimental-features = nix-command flakes\n%s' "${NIX_CONFIG:-}")"
+
 # Off-repo material keyed by <config>: pre-generated SSH host keys (install)
 # and per-config sops age keys (flash).
 #