I'm newbie on both ruby and linux, so I'm sure this is trivial but I don't know yet. I currently have ruby 1.8.7 installed and I want to update it to ruby 1.9. How can I do that?
sudo apt-get install ruby1.9
should do the trick.
You can find what libraries are available to install by
apt-cache search <your search term>
So I just did
apt-cache search ruby | grep 9 to find it.
You'll probably need to invoke the new Ruby as
ruby1.9, because Ubuntu will probably default to 1.8 if you just type