Install factory:
```sudo gem install -n /usr/local/bin compass```

To install RVM, do the following.

```bash
mkdir -p ~/.rvm/src && cd ~/.rvm/src && rm -rf ./rvm && \
git clone --depth 1 git://github.com/wayneeseguin/rvm.git && \
cd rvm && ./install
```

Add the following line to the end of your .profile or .bash_profile or .bashrc file.

```
if [[ -s $HOME/.rvm/scripts/rvm ]]; then
  source $HOME/.rvm/scripts/rvm;
fi
```

```
Try out RVM.
rvm install 1.8.7
rvm install 1.9.2
rvm --default 1.9.2
ruby -v
which ruby
gem install rails
```