cespare

  $ mkdir /tmp/foo
  $ touch /tmp/nodelete
  # create and delete 100k files
  $ for i in $(seq 1 10); do bash -c 'for i in $(seq 1 10000); do rm $(mktemp /tmp/foo/XXXXXX); done' &; done; wait
  ...
  $ time rmdir /tmp/foo
  rmdir: failed to remove '/tmp/foo': Directory not empty
  rmdir /tmp/foo  0.00s user 0.02s system 91% cpu 0.024 total
  $ time rmdir /tmp/foo
  rmdir: failed to remove '/tmp/foo': Directory not empty
  rmdir /tmp/foo  0.00s user 0.00s system 81% cpu 0.003 total