RVM

Ruby Version Manager

https://rvm.io//

http://cheat.errtheblog.com/s/rvm/

Install RVM

Follow the latest instructions. Choose the non-sudo "single user install" unless you have a good reason not to.

https://rvm.io/rvm/install/

May need to source /etc/profile.d/rvm.sh to get things working.

Update RVM:

rvm get stable

Installing Ruby

First, fix any dependencies listed here:

rvm requirements

Show installed rubies:

rvm list

Show all available rubies:

rvm list known

Install:

rvm install 1.9.3                # Latest known patch level
rvm install 1.9.3 -j 3           # Parallel compile, set to # of CPU cores

Remove a ruby:

rvm remove 1.9.3

Gemsets

rvm list gemsets # List rubies and gemsets
rvm gemset list  # List gemsets for current ruby

Create a new gemset:

rvm ruby-1.9.3-p194@rails2314 --create

Switch to a particular gemset:

rvm gemset use rails2314

Now you can use gem or bundle install as usual to install the needed gems.

Remove a gemset:

rvm gemset use albinochipmunk
rvm gemset delete albinochipmunk

Project Setup and Best Practices

https://rvm.io//rvm/best-practices/

https://rvm.io/workflow/rvmrc/

cd ~/projects/my_project/
rvm --rvmrc --create 1.9.1@my_project

Now when you cd to the my_project directory, your ruby and gemset will change automatically:

cd ~/projects/my_project
[ruby-1.9.1-p243] (0) $ ruby -v
  ruby 1.9.1p243 (2009-07-16 revision 24175) [i686-darwin10.2.0]
[ruby-1.9.1-p243] (0) $ gem env gemdir
  /Users/wayne/.rvm/gems/ruby/1.9.1@my_project