Setting Ruby to version 1.9.2 as default in Mac OS X Lion

After installing version 1.9.2 of Ruby I suffered a little bit to get RVM (Ruby Version Manager) to use version 1.9.2 as the default version of Ruby in Terminal. These are the steps I followed to get it to work correctly:

Install RVM and edit Profile scripts

If you haven’t done so, install Ruby Version Manager (RVM). First, use the following bash script to install RVM:

bash << (curl -s https://rvm.beginrescueend.com/install/rvm)

Usually, in Mac OS X environments the Terminal.app uses bash. Therefore your Terminal startup scripts are set to use .bash_profile and .bashrc. In order to avoid confusion, it’s better to use one or the other. Modify your .bash_profile file using your favorite text editor (if you would like to open the file from Finder install Tinker Tools first so that you can see all hidden files and directories in Finder). Add the following to your .bash_profile file so that it calls the .bashrc file automatically when you open a Terminal session:

a) Edit .bash_profile:

if [ -f ~/.bashrc ]; then
source ~/.bashrc
fi

b) Now edit .bahsrc:

Add the following to the end of your .bashrc file:

[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm" # Load RVM function
[[ -r $rvm_path/scripts/completion ]] && . $rvm_path/scripts/completion #rvm tab completion

c) Add PATHs, this is important because if you don’t have the right PATHs when using Terminal you won’t be able to use profile specific applications (such as Ruby) that you have installed from within your profile. As an example I have copied and pasted my own PATHs section:

export PATH=/Library/Frameworks/Python.framework/Versions/2.7/bin:$HOME/.rvm/gems/ruby-1.9.2-p290/bin:$HOME/.rvm/scripts/rvm:/Developer/usr/bin:/Developer/usr/libexec:/Developer/usr/sbin:
/Developer/usr/local/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin:$HOME/bin:
/usr/libexec:/usr/local/git:/usr/local/mysql/bin

export CC=gcc-4.2

Set Ruby to default to version 1.9.2

First, make sure that the system version of Ruby is ok:

$ ruby -v

That should return your system Ruby version, which as of this writing is 1.8.7 with Mac OS X Leopard and Mac OS X Lion.

ruby 1.8.7 (2010-01-10 patchlevel 249) [universal-darwin11.0]

Now, let’s use RVM to se the default Ruby interpreter to 1.9.2:

$ rvm -default use 1.9.2

Now type ruby -v again and that should return version 1.9.2:

$ ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin11.0.0]

This should save you a few headaches, it’s a pain to have to type $ ruby use 1.9.2 every time you open a Terminal.