Rbenv

https://github.com/sstephenson/rbenv

Setup

Install the rbenv and ruby-build packages on Ubuntu.

Add to shell:

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

Restart shell. Then test like this:

$ type rbenv
#=> "rbenv is a function"

Installing Ruby Versions

This depends on having the ruby-build package.

# list all available versions:
$ rbenv install -l

# install a Ruby version:
$ rbenv install 2.0.0-p247

Downloads source, compiles, and stores the result in ~/.rbenv/versions/

rbenv rehash

$ rbenv rehash

Installs shims for all Ruby executables known to rbenv (i.e., ~/.rbenv/versions/*/bin/*). Run this command after you install a new version of Ruby, or install a gem that provides commands.

rbenv local

$ rbenv local 1.9.3-p327

Creates a .ruby-version file in the current directory.

rbenv versions

$ rbenv versions
  1.8.7-p352
  1.9.2-p290
* 1.9.3-p327 (set by /Users/sam/.rbenv/version)
  jruby-1.7.1
  rbx-1.2.4
  ree-1.8.7-2011.03

rbenv version

$ rbenv version
1.8.7-p352 (set by /Volumes/37signals/basecamp/.ruby-version)

rbenv which

$ rbenv which irb
/Users/sam/.rbenv/versions/1.9.3-p327/bin/irb