add a script to prune

prune-backups.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+REPO="${1:-}"
+
+if test -z "$REPO"; then
+  echo "USAGE: ${0:-} some.remote-name.com:repo"
+  echo "You can also add additional arguments, e.g. --rsh"
+  exit 1
+fi
+
+exec borg prune -d 7 -w 4 -m 60 -y 10 "$@"