Recently updated posts

I want to add a “recently updated categories” section to my sidebar. This will only display the titles of the posts, and link to the category, nothing more. I hae been searching and haven’t been able to find something. I figure it’d be just a couple tags to insert.

I was trolling around the docs and the only thing I could find relating to my problem is a “link category”. I’m not sure if this is what I should be using? If so, how does it know to only display recent categories if its just a list of links?