Mac及び各種Linuxでruby-buildとrbenvをインストールしてruby環境を用意する ref: http://qiita.com/sifue/items/b7d252b18ebbae636fa9

file0.sh

git clone git://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build
cd ~/.rbenv/plugins/ruby-build
sudo ./install.sh
mkdir -p ~/local/src
mv  ~/.rbenv/plugins/ruby-build ~/local/src
rm -rf ~/.rbenv
git clone git://github.com/sstephenson/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/shims:$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc
echo 'eval "$(rbenv init -)"' >> ~/.zshrc
source ~/.zshrc
rbenv install 2.0.0-p353
rbenv rehash
rbenv global 2.0.0-p353

file1.sh

cd ~/.rbenv
git pull origin master
cd ~/.rbenv/plugins/ruby-build
git pull origin master
rbenv install --list
rbenv install 2.0.0-p247
rbenv rehash
rbenv global 2.0.0-p247