How to manage multiple gemsets and ruby versions with RVM?

Question

I am really confused by the explanations given in RVM website. The relation between different ruby interpretors and gemsets are not clear to me. According to me, it is like

Answer 1

Here is how I like to do it...

1. Install a ruby with RVM
2. Switch to/use that ruby
3. Create a gemset for a project
4. Switch to/use that gemset
5. Install gems needed
6. create an alias that points to my chosen ruby & gemset
7. switch to/use that new alias (again, associated w/ a project)

Do this as many times necessary for your different projects that you want to keep separate from eachother.

Example:

$ rvm install ruby-1.9.2
...
$ rvm list

rvm rubies

=> ree-1.8.7-head [ i386 ]
   ruby-1.9.2-head [ i386 ]
   ruby-1.9.2-preview3 [ i386 ]

$ rvm use ruby-1.9.2-preview3

info: Using ruby 1.9.2 preview3
$  rvm gemset create my_project

info: Gemset 'my_project' created.
rvm gemset use my_project

info: Now using gemset 'my_project'
$ gem install httparty
When you HTTParty, you must party hard!
Successfully installed crack-0.1.8
Successfully installed httparty-0.6.1
2 gems installed
$ rvm alias create my_project ruby-1.9.2-preview3@my_project

info: Creating alias my_project for ruby-1.9.2-preview3@my_project.

info: Recording alias my_project for ruby-1.9.2-preview3@my_project.
$ rvm use my_project

info: Using ruby 1.9.2 preview3 with gemset my_project
$ ....

Now I have an entire environment dedicated to a particular project. This is great because I can experiment with all sorts of different gems/versions without worrying about stomping all over other projects that have very specific requirements.

Good luck!

Answer 2

To add onto Brian's answer above, you can also use .rvmrc files to dynamically switch gemsets when entering new project directories.

simply run the following:

rvm rvmrc create ruby-1.8.7-p358@my_project

This will help stop confusion which I had when switching and forgetting to change gemsets

UPDATE .rvmrc files are in the process of being dropped for the newer .ruby-version file see discussion here: https://gist.github.com/fnichol/1912050