How to Install rbenv on OS X

rbenv is a tool for managing ruby versions. It's similar to RVM but doesn't require configuration files. Instead of using gemsets, the user is expected to make use of bundler to manage gem dependencies.

Installation

Install rbenv from GitHub:

$ git clone git://github.com/sstephenson/rbenv.git ~/.rbenv

Add the following lines to your ~/.zshrc or ~/.bash_profile.

export PATH="$HOME/.rbenv/bin:$PATH"
eval "$(rbenv init -)"

Restart your terminal then install ruby-build:

$ cd
$ git clone git://github.com/sstephenson/ruby-build.git
$ cd ruby-build
$ [sudo] ./install.sh

Install the latest version of Ruby (1.9.3-p0) and activate it:

$ rbenv install 1.9.3-p0
$ rbenv global 1.9.3-p0
$ rbenv rehash

Restart the terminal again, then update RubyGems:

$ gem update --system

rbenv makes use of shims for all binaries, including gems. When you install a new gem, you need to run rbenv rehash to generate the shims. This can be done automatically by installing the rbenv-rehash gem:

$ gem install rbenv-rehash

Last but not least, you'll probably want to install bundler:

$ gem install bundler

rbenv can make use of gemsets by installing the rbenv-gemset plugin, however, the preferred method is to use bundler to manage gem dependencies. If you use oh my zsh, you can activate the bundler plugin, which allows you to run gem executables without prefixing them with bundle exec.

Just add the following to your ~/.zshrc:

plugins=(bundler)

And, just in case you want a system wide installation on a linux server, here's the code to set that up on Ubuntu 10.04, courtesy of @benwoodward.