Setup Rails on Mountain Lion


3 min read

A humble (*caught) guide for helping setup Rails environment on Mountain Lion with rbenv.

Install Xcode and it's friends...

First we need Xcode's Command Line Tools for install copies of the core command line tools and system headers into system folders.

If you don't need Xcode, you can download "Command Line Tools for Mountain Lion" from Apple developer site and install that, it's free but need an registed apple developer account. You can save about 4GB diskspace for doing so. Otherwise follow the steps below:

  1. Download and install Xcode from App Store first.

  2. Open Xcode, press Xcode -> preferences on the menu bar.

  3. Switch to Downloads -> Components section,

  4. install "Command Line Tools".

Install Homebrew

We choose Homebrew as our package manager, just like apt or yum for linux. After this step, you can use brew install something to install lots of useful tools, e.g., MySql, imagemagick and Node.js. Then we use Homebrew to install apple-gcc for compile ruby from the source, Git for up-to-date version control.

Open Terminal, paste this command beneath than Enter

ruby -e "$(curl -fsSkL"

Essential components

  • Execute each command followed:
brew install git
  • Optional
brew install mysql imagemagick

rbenv with Shell configs

Then we use rbenv and ruby-build for install multiple ruby version. But if you're kind of RVM's guy, just skip this section and go for it.

brew install rbenv ruby-build

After install the rbenv, we need to adjust our shell config to execute rbenv while system boot up.

  • In Terminal, execute each commands followed. (Note: if you're using ZSH, execute the ZSH part instead.)


echo 'if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi' >> ~/.bash_profile && source ~/.bash_profile


echo 'if which rbenv > /dev/null; then eval "$(rbenv init - zsh)"; fi' >> ~/.zshenv; source ~/.zshenv

Install Ruby

Whoa, the goal is just few steps far. Let's install all the ruby versions we need. Aren't we struggle all the way, just for that? Cross the fingers, guys.

  • In Terminal, execute each commands followed.
rbenv install 2.0.0-p247; rbenv rehash; rbenv global 2.0.0-p247
  • Optional: If you need Ruby Enterprise Edition, execute the commands followed.

Replace ; wich && in bash

Install Apple GCC

  • In Terminal, execute each commands followed.
sudo chown -R `whoami` /usr/local && brew update && brew tap homebrew/dupes && brew install apple-gcc42

If you need Ruby Enterprise Edition

CPPFLAGS=-I/opt/X11/include \
CC=/usr/local/bin/gcc-4.2 \
rbenv install ree-1.8.7-2012.02; rbenv rehash

Install important gems

Finally, it's done! Buy yourself a drink, you worth it! At the end let's install some gems and prepare for the party on Rails!

  • In Terminal, execute each commands followed.
gem install bundler rails