How to install ruby gems without sudo

I want to install a Ruby Gem to my computer, but since I don't have an administrator account I can't use sudo. How do I install a Gem without sudo, and what (if any) privileges do I loose? This is in reference to this question I asked on Stack Overflow. Update: - I installed RVM, but I got these two errors: WARNING: your RVM loading script /etc/profile.d/rvm.sh is deprecated and causes you to have umask g+w set in your shell, run rvm get head --auto-dotfiles again to fix your scripts. And WARNING: You have '~/.profile' file, you might want to load it, to do that add the following line to '/Users/CalebKleveter/.bash_profile': source ~/.profile I ran rvm get head --auto-dotfiles, but I got the same errors again. Any suggestions on what to do? And what does the second error message want me to do? Update 2: - I tried gem install cocoapods and I got the error in my other post, then I tried rvm gem install cocoapods and I got "Please note that rvm gem ... was removed, try gem install cocoapods or rvm all do gem install cocoapods instead. ( see: 'rvm usage' )" so I tried rvm all do gem install cocoapods and it just started a new command prompt, that is what is supposed to happen, right?