I’m in the process of getting my new MacBook Air setup. This involves editing my bash profile, setting system preferences, installing my favorite apps and getting the system ready for development. It used to take days to get a new Mac completely setup. I was able to get this new Air completely setup within a few hours. Homebrew makes it incredibly simple to install the needed tools. About the only thing I don’t use it for is to install Ruby and Rails. For this you’ll need to do a little system setup.

GCC Is MIA

With XCode 4.2+ GCC is no longer included. Instead it has been replaced by LLVM (Low Level Virtual Machine), Apple’s favorite new compiler. They currently use it for their MacRuby project. The problem is that you will need GCC if you plan to install Ruby via rbenv (which you really should be using).

Installing GCC On Lion

Kenneth Reitz has created a GCC installer for OS X 10.7. You can download the installer on GitHub/osx-gcc-installer.

Installing Homebrew

 $ /usr/bin/ruby -e "$(curl -fsSL https://raw.github.com/gist/323731)"

Installing rbenv

 $ brew update
 $ brew install rbenv
 $ brew install ruby-build

 $ echo 'eval "$(rbenv init -)"' >> ~/.bash_profile

Installing Ruby

 $ rbenv install 1.9.3-p0

Set 1.9.3-p0 as the default like this (optional):

 $ rbenv global 1.9.3-p0

Rebuild the shim binaries.

 $ rbenv rehash

Verify the installation and see all installed versions of Ruby:

 $ rbenv versions

Installing Rails

 $ gem install bundler
 $ gem install rails

If all goes well you’ll end up with a fully-functional environment ready for Rails development.