these are the steps i take for setting up rbenv on a new ubuntu vm. notice that with oh-my-zsh installed the bash_profile changes to zshrc.

ubuntu rbenv setup

sudo apt-get install libssl-dev zlib1g-dev
sudo apt-get install libreadline-dev


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to switch from rvm to rbenv:

first call 'rvm implode'
and remove any mention of rvm from the ~/.profile, ~/.bash_profile, ~/.bashrc files

git clone git://github.com/sstephenson/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile
echo 'eval "$(rbenv init -)"' >> ~/.bash_profile

this reloads your shell and should not output anything if its working: exec $SHELL -l

git clone git://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build

the glorified: rbenv rehash

rbenv install 1.9.3-p327
rbenv global 1.9.3-p327

gem install bundler

to make sudo work with the ruby you need this link:
  sudo ln -s /home/dkelman/.rbenv/shims/ruby /usr/bin/ruby
  sudo ln -s /home/dkelman/.rbenv/shims/god /usr/bin/god