RVM is one of those tools that you add to your arsenal that makes you go back and think how you ever got by without it before. This is particularly true if you are working on multiple projects, all of which have their own Ruby versioning/gem set requirements. It's incredible how trivial management has become when I'm dealing with 1.8.7, 1.9.2 and JRuby 1.5.2 (concurrently) on an almost daily basis.
Another important think to note when using RVM is to not use 'sudo' when installing gems. It is easy get caught up in a README or tutorial and execute 'sudo gem install...' as listed in the document. Unfortunately, this installs the gem in root's environment, which isn't configured with RVM goodness using the default installation method and you'll quickly end up with all sorts of problems and obscure error messages.
Personally I find it a bit of an overkill for me, and I doubt that it plays nice with other package managers... (if anyone knows more I'd like to hear more about it).<p>That said I understand people doing a lot of work on other people's computers (e.g. Ruby on Rail) may find it really useful.<p>Personally now it's 1.9.2 all the way! :D
After installing RVM if gem is giving you a zlib error, this info was useful on both Ubuntu and Debian:
<a href="http://rvm.beginrescueend.com/packages/zlib/" rel="nofollow">http://rvm.beginrescueend.com/packages/zlib/</a><p>edit:
I put up a short tutorial on how to get this running on Lenny:
<a href="http://www.reedglaw.com/rails/InstallRailsRVM" rel="nofollow">http://www.reedglaw.com/rails/InstallRailsRVM</a>
<i>we do not need to use sudo to install gems, as everything is kept in ~/.rvm</i><p>It's not that you don't need to, it's that you shouldn't. Using sudo to install gems will do so outside of your rvm gemset, and so the gems you install this way will not be available to your app using the gemset.
How does that gemset stuff fit in with Bundler? It's much easier for us to just keep Gemfile in the git repo, run "bundle install", and then let Bundler worry about installing gems and keeping a clean gem environment.