Batch convert ebooks qustion

[Linux for blind general discussion]

So, I've a fun question. I bought a box set of ebooks that got delivered 
in .epub format. I'd like to convert them to .txt, the ebooks are DRM 
free, but I don't want to go through one at a time. So...

Can I use ebook-convert, I can't do ebook-convert *.epub *.txt


So how can I tell ebook-convert to take all the files of a certain type 
and convert to my desired output type?