rewrite erase-home-darlings service in clojure

README.org

@@ -129,8 +129,7 @@ builtins.mapAttrs mkHost (builtins.readDir ./hosts)
   boot.initrd.systemd.initrdBin = with pkgs; [
     zfs
     coreutils
-    gnugrep
-    gawk
+    babashka
   ];
 
   boot.initrd.systemd.services.erase-darlings = {
@@ -168,48 +167,17 @@ builtins.mapAttrs mkHost (builtins.readDir ./hosts)
     after = [
       "home.mount"
     ];
-    path = [ pkgs.zfs pkgs.coreutils pkgs.gnugrep pkgs.gawk pkgs.util-linux ];
+    path = [ pkgs.zfs pkgs.babashka ];
     # unitConfig.DefaultDependencies = "no";
     serviceConfig = {
       Type = "oneshot";
       RemainAfterExit = true;
+      ExecStart =
+        let script = ./erase-home-darlings.clj;
+        in ''${pkgs.babashka}/bin/bb "${script}" 3'';
     };
     stopIfChanged = false;
     restartIfChanged = false;
-    script = /* bash */ ''
-      set -xe
-      set -o pipefail
-
-      command -v findmnt || echo "can't find findmnt on PATH"
-      command -v awk || echo "can't find awk on PATH"
-
-      # findmnt -no TARGET rpool/darlings/persist
-      PREVDIR=$(findmnt -no TARGET rpool/darlings/persist)/previous
-      # PREVDIR=/sysroot/persist/previous
-
-      echo "PREVDIR=$PREVDIR"
-      mkdir -p $PREVDIR/home
-
-      [ -e $PREVDIR/home/3 ] && rm -rf $PREVDIR/home/3
-      [ -e $PREVDIR/home/2 ] && mv $PREVDIR/home/2 $PREVDIR/home/3
-      [ -e $PREVDIR/home/1 ] && mv $PREVDIR/home/1 $PREVDIR/home/2
-
-      DIFFFILE="$(mktemp "erase-home-darlings-zfs-diff-XXXXXX")"
-
-      zfs diff -HF rpool/local/home@blank rpool/local/home \
-          > "$DIFFFILE"
-      awk '{if ($2 == "F" || $2 == "/") print $3}' < "$DIFFFILE" \
-        | while read -r line; do
-            DEST="$PREVDIR/home/1/$(dirname "$line")/$(basename "$line")"
-            mkdir -p "$(dirname "$DEST")"
-            mv "$line" "$DEST" && \
-              echo "$line -> $DEST"
-          done \
-          && echo ">> previous home backed up to $PREVDIR/home/1 <<"
-
-      zfs rollback -r rpool/local/home@blank \
-        && echo ">> home rolled back <<"
-    '';
   };
 
   # boot.loader.grub = {