Upgrading Ruby on Mac OS X

I am reading the book Programming Ruby and am looking to upgrade the version of Ruby on my computer. I run Mac OS X Snow Leopard and doing ruby -v in the command line shows I am running Ruby 1.8.7.

I installed MacPorts and ran the sudo port install ruby19 command but whenever I type ruby -v, it still shows Ruby 1.8.7.

Could anyone help with this? Thank you.

What is the latest version of Ruby for Mac?

The current stable version is 3.1. 2.

What is Ruby on macOS X?

ruby-build is a plugin for rbenv that allows you to compile and install different versions of Ruby. ruby-build can also be used as a standalone program without rbenv. It is available for macOS, Linux, and other UNIX-like operating systems.

The tool "rvm" is pretty good. It stands for Ruby Verson Manager I think, and the developer is good at support in the irc channels. You can install multiple versions of ruby along side each other pick the ones you want to use.

http://rvm.io