Rails on Jaunty
One of these days, aptitude install rails will be all that is needed. With Jaunty, this is not quite the case, but nearly so. What you get is Ruby 1.8.7 (good), gem 1.3.1 (good), and rails 2.1.0 (vintage June 2008). Unfortunately, any rails commands will result in nine lines of the form /usr/lib/ruby/1.8/xmlsimple.rb:275: warning: already initialized constant. Upgrading to 2.3.2 (vintage March 2009) is as simple as:
sudo gem install rails export PATH=/var/lib/gems/1.8/bin/:$PATH
This also eliminates the warnings. The last line should be dropped into your .bashrc file.