How to remove docker aufs folder?
<p>I've uninstalled docker with the following command</p>

<p><code>sudo apt-get purge docker-engine</code></p>

<p><code>sudo apt-get autoremove --purge docker-engine</code></p>

<p>The above command works fine, no problem. But when I try to run <strong><code>sudo rm -rf /var/lib/docker</code></strong> as instructed in <a href="https://docs.docker.com/engine/installation/linux/ubuntulinux/#uninstallation" rel="nofollow">Docker docs</a>, I get the following error </p>

<p><strong><code>rm: cannot remove '/var/lib/docker/aufs/mnt/04fc3de09910bf8fae3d0430b0debbf3032d480bef4ced9f40b1f532bf478ef9': Is a directory</code></strong></p>

<p>What should I do to remove this content?</p>