Did I set up mongodb correctly?
<p>I'm trying to create a MEAN stack, but I don't seem to be able to get it to work. I have installed mongodb but when I type <code>mongod</code> I get an error on the output that reads:</p>

<pre><code>I STORAGE  [initandlisten] exception in initAndListen: 98 Unable to create/open lock file: /data/db/mongod.lock errno:13 Permission denied Is a mongod instance already running?, terminating
</code></pre>

<p>What does this mean and how can I fix it?</p>