Impermanence.

machines/lebesgue/tools/server/fs-diff

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# fs-diff.sh
+# run on server.
+set -euo pipefail
+
+if [[ -f /mnt ]]; then
+        mkdir /mnt
+fi
+
+if ! mountpoint /mnt > /dev/null; then
+        mount -t btrfs /dev/disk/by-label/NIXROOT /mnt
+fi
+
+OLD_TRANSID=$(sudo btrfs subvolume find-new /mnt/root-blank 9999999)
+OLD_TRANSID=${OLD_TRANSID#transid marker was }
+
+sudo btrfs subvolume find-new "/mnt/root" "$OLD_TRANSID" |
+sed '$d' |
+cut -f17- -d' ' |
+sort |
+uniq |
+while read path; do
+  path="/$path"
+  if [ -L "$path" ]; then
+    : # The path is a symbolic link, so is probably handled by NixOS already
+  elif [ -d "$path" ]; then
+    : # The path is a directory, ignore
+  else
+    echo "$path"
+  fi
+done