Hello. First off discussions have moved to talk.tiddlywiki.org
. You will have much quicker answers to your questions there.
I will assume you are new to tiddlywiki. There are two forms a tiddlwiki can take - 1. a single html file and 2. a nodejs server.
The link you give describes the first form and I don't see any reference to the command you are asking about. There is a link to setting up a nodejs server on that page so maybe you followed it?
Unless you are familiar with setting up servers I would suggest using the first method and stick to the instructions on the page you referenced - don't follow the link about exporting the wiki.