Ubuntu + RVM: Ruby Install – There was an error(23)

After a new install of RVM on Ubuntu, you may run into the error “There was an error(23)” in conjunction with a file write or folder creation permission error. This is caused when, for some reason, RVM does not properly add your Ubuntu user to the RVM group after it was installed. To correct this error, you need to complete the following steps, and executing the following commands:

Execute in terminal:
rvm group add rvm "$USER"

Log out of Ubuntu and log back in. If it still fails, you may need to have RVM fix its system permissions with the command:

Execute in terminal:
rvm fix-permissions

Ubuntu 12 : RVM : Default Gemset not Working/Setting

When setting up a Ruby/Rails development environment utilizing Ubuntu 12.04 LTS you may find yourself running into issues with setting your RVM default Gemset.

I attempted to set the default Gemset using every possible combination of the command rvm –default use 1.9.3-p286@corerivalry but every time I closed my terminal and re-opened it my default Ruby was set, but my Gemset was continually being set back to (default).
After much searching and frustration I ran into the –rvmrc command which creates a file (.rvmrc) that specifies the Ruby version as well as the Gemset to use for an individual project. After running the command, each time I opened my terminal in my Rail application’s root folder my Ruby and Gemset are exactly what I intend them to be.
The command:
rvm use 1.9.3-p286@rails3 --rvmrc