This is actually really easy, but some reason it didn’t quite stick in my mind until recently, so I thought I’d note it here, and perhaps it might help someone else who’s similarly challenged :).
If you haven’t set up an .rvmrc
(Which, to be fair you probably should have done)
If you really can’t remember which gemset, start with:
$ rvm gemset list
$ rvm gemset use [gemset]
$ gem list
Is all you need to show all the currently loaded gems.
If you have setup .rvmrc
The all you need is run the last ‘gem list’ command. The essential point to remember is that once you’ve switched to your chosen gemset and ruby version, you just execute your gem commands without the ‘rvm’ prefix. (see the bottom of that page).
Whilst we’re on the subject of things I should have done already, I should probably have already setup an rvm prompt too. If I ever get round to sorting these things out properly, I might even write some sort of post about how to set up your rvm environment.
Or you could just look at this blog post, which is easily the most helpful and lucid description of setting up RVM I’ve read so far. Getting started with RVM. It’s a bit old, so there might be aspects that are a little out of date, but most of it still seems to be applicable.