Create onchange script

Signed-off-by: Oliver Davies <oliver@oliverdavies.uk>

modules/scripts/onchange.nix

@@ -0,0 +1,23 @@
+{
+  flake.modules.homeManager.base =
+    { pkgs, ... }:
+    {
+      home.packages = [
+        (pkgs.writeShellApplication {
+          name = "onchange";
+
+          runtimeInputs = with pkgs; [
+            coreutils
+            entr
+          ];
+
+          text = ''
+            PATTERN="$1"
+            shift 1
+
+            find . -path "$PATTERN" -type f | entr -cs "$@"
+          '';
+        })
+      ];
+    };
+}