just diffing and triplet

flake.lock

@@ -1056,16 +1056,16 @@
     },
     "systems_5": {
       "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "lastModified": 1776166891,
+        "narHash": "sha256-bI8yrEGjrohR5hkQox7UrxDH7XqrYMwI8SL/LrJ1+S8=",
         "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "repo": "triplet",
+        "rev": "6de7bc09397911ce03636afbcf6118745ab2cda0",
         "type": "github"
       },
       "original": {
         "owner": "nix-systems",
-        "repo": "default",
+        "repo": "triplet",
         "type": "github"
       }
     },

flake.nix

@@ -95,6 +95,7 @@
               nvf
               cachix
               jq
+              nvd
               devour-flake
               agenix
               deadnix
@@ -173,7 +174,7 @@
     flake-parts.url = "github:hercules-ci/flake-parts";
     flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
 
-    systems.url = "github:nix-systems/default";
+    systems.url = "github:nix-systems/triplet";
 
     treefmt-nix.url = "github:numtide/treefmt-nix";
     treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";

justfile

@@ -21,3 +21,27 @@ update:
 
 cache:
 	devour-flake . | cachix push callumio-public
+
+_build host:
+    @nix build .#nixosConfigurations.{{host}}.config.system.build.toplevel --no-link --print-out-paths
+
+baseline:
+    @just _build artemis > /tmp/artemis.before
+    @just _build hermes  > /tmp/hermes.before
+    @echo "baseline saved:"
+    @echo "  artemis → $(cat /tmp/artemis.before)"
+    @echo "  hermes  → $(cat /tmp/hermes.before)"
+
+# baseline one host
+baseline-host host:
+    @just _build {{host}} > /tmp/{{host}}.before
+    @echo "{{host}} baseline → $(cat /tmp/{{host}}.before)"
+
+# diff one host against its saved baseline
+diff-host host:
+    @nvd diff $(cat /tmp/{{host}}.before) $(just _build {{host}})
+
+# diff both hosts
+diff:
+    @just diff-host artemis
+    @just diff-host hermes