Cleaning old packages

src/SUMMARY.md

@@ -11,6 +11,7 @@
   - [GUI](./configuration/GUI.md)
   - [Home-manager](./configuration/hm.md)
   - [How to find new software and configure](./configuration/new.md)
+  - [Cleaning old packages](./configuration/clean.md)
 - [Building your own software](./build/index.md)
   - [Dev shells](./build/devshell.md)
   - [Packages](./build/packages.md)

src/configuration/clean.md

@@ -0,0 +1,16 @@
+# Cleaning old packages
+
+By default, packages installed will be kept after each rebuild, even if they are not active anymore.
+You can manually garbage collect with `nix-collect-garbage -d` to remove all the old generations.
+
+One can however do this automatically using the following:
+```nix
+nix.gc = {
+  automatic = true;
+  persistent = true;
+  dates = "weekly";
+  options = "--delete-older-than 14d";
+};
+```
+This will check every week, and delete packages that aren't used that active, that also are older than 14 days.
+If the timing of the check was missed, due to the system being powered down or similar, it will attempt at the closest time it can.