I did this by adding the saucy (13.10) repositories back to my
sudo -H gedit /etc/apt/sources.list
deb http://gb.archive.ubuntu.com/ubuntu/ saucy main restricted after the first set.
- Save the file and exit the editor.
sudo apt-get update
sudo apt-get install ruby1.8
sudo apt-get install rubygems
Probably isn't the best way, but it seemed to work for me. I had an older project with compass/sass that was failing on ruby 1.9 but now works as before.
I noticed that installing ruby 1.8 also installed a package called
ruby-switch. Might be able to switch between 1.8 and 1.9 with this utility, although I haven't played with it and RVM is probably a better solution for switching ruby versions.