diff --git a/scripts/remove_old_packages b/scripts/remove_old_packages
index 924a9ad..f4ecaed 100755
--- a/scripts/remove_old_packages
+++ b/scripts/remove_old_packages
@@ -38,6 +38,7 @@ def main(args):
     except TypeError:
       print('Bad things happen: %s' % v)
       raise
+
     for pkg, f in v[:-args.keep]:
       if args.dry_run:
         print('would remove %s.' % f)
@@ -45,12 +46,18 @@ def main(args):
         print('removing %s.' % f)
         remove_pkg(f)
 
+    if args.show_kept_fd >= 0:
+      for _, f in v[args.keep:]:
+        os.write(args.show_kept_fd, f.encode('utf-8') + b'\n')
+
 if __name__ == '__main__':
   parser = argparse.ArgumentParser(description='remove old Arch Linux packages')
   parser.add_argument('-n', '--dry-run', action='store_true',
                       help='dry run')
   parser.add_argument('-k', '--keep', metavar='N', type=int, default=2,
                       help='how many versions to keep. Default is 2')
+  parser.add_argument('--show-kept-fd', metavar='FD', type=int, default=-1,
+                      help='write kept package paths to fd FD, one per line')
   parser.add_argument('packages', metavar='PACKAGE', nargs='+',
                       help='package files to check')
   args = parser.parse_args()