Firstly, get the dropbox share link. It will look like this

https://www.dropbox.com/s/ad2arn440pu77si/test.txt

Then add a ?dl=1 to the end of that url and a -O filename so that you end up with something like this:

wget https://www.dropbox.com/s/ad2arn440pu77si/test.txt?dl=1 -O test.txt

Now you can easily get files onto your linux box that aren’t available elsewhere.