diff --git a/scripts/umount-all-backups b/scripts/umount-all-backups
new file mode 100755
index 0000000..e1882aa
--- /dev/null
+++ b/scripts/umount-all-backups
@@ -0,0 +1,14 @@
+#!/usr/bin/perl
+use v5.12;
+use warnings;
+
+chdir("/");
+for my $backup_dir (glob("/backup/*")) {
+    next unless -f "$backup_dir/active";
+    say STDERR "unmounting $backup_dir";
+    system("/bin/umount", $backup_dir);
+    if ($backup_dir =~ m{(luks-[^/]+)}) {
+        say STDERR "closing $1";
+        system("/sbin/cryptsetup", "close", $1)
+    }
+}