So I used these commands:
sudo apt-get install ruby 1.9.3 cd /etc/alternatives sudo ln -sf /usr/bin/ruby1.9.3 ruby
from http://stackoverflow.com/questions/11078166/how-do-i-install-ruby-1-9-3-on-ubuntu-without-rvm in order to get ruby 1.9.3 and make it the default. That appears to have worked fine.
Now when I attempt to use gem install it tells me the gems are already the latest. However, when I attempt to run a script it tells me it can't find the gem I require on the first line. Long story short, this script didn't work in ruby 1.8.7 due to an error farther down in the code but did get past the require lines without issue.
So I expected to and assume I need to reinstall all my 1.8.7 gems for 1.9.3 or at least figure out how to point 1.9.3 at the gems I've installed.
How do I do get usable gems for 1.9.3?