The thing is that the rvmrc has the jruby version env set. So I need to load it first. And it contains an 'rvm use' which I don't want to fail. I suppose I can slim the rvmrc down to just include the environment and then all I would need to do is source the rvmrc? Thoughts?
I don't believe you need to source the rvmrc. The line I pasted above does all the necessary things that "rvm use $BUILD" would do for a shell, without all the things that require an interactive shell.