diff --git a/NixOS.md b/NixOS.md
index 077f48c..9c5411c 100644
--- a/NixOS.md
+++ b/NixOS.md
@@ -221,6 +221,13 @@ ls -1 /nix/var/nix/profiles/ | sort -t'-' -n -k2 | tail -n 1
 
 Compare current with previous profile:
 
+```shell
+# https://discourse.nixos.org/t/how-to-know-what-nixpkgs-changes-affect-me/18142/6
+prev="$(ls -r /nix/var/nix/profiles/ | grep -E 'system\-' | sed -n '2 p')"
+curr=/nix/var/nix/profiles/system
+nix --extra-experimental-features nix-command store diff-closures /nix/var/nix/profiles/"${prev}" "${curr}"
+```
+
 ```shell
 # https://stackoverflow.com/a/36641298
 prev="$(ls -1 /nix/var/nix/profiles/ | sort -t'-' -n -k2 | tail -n 2 | head -n 1)"