手動安裝 ruby 版本, 要使用 ln 去 連結.

手動安裝1.9.1 and gem 1.3.5

來源
Install Ruby 1.8 (MRI)

apt-get -y install ruby1.8-dev ruby1.8 ri1.8 rdoc1.8 irb1.8 libreadline-ruby1.8 libruby1.8 libopenssl-ruby
ln -s /usr/bin/ruby1.8 /usr/bin/ruby
ln -s /usr/bin/rdoc1.8 /usr/bin/rdoc
ln -s /usr/bin/irb1.8 /usr/bin/irb
ln -s /usr/bin/ri1.8 /usr/bin/ri

Install RubyGems (from source)

curl http://rubyforge.org/frs/download.php/60718/rubygems-1.3.5.tgz | tar -xzv
cd rubygems-1.3.5 && ruby setup.rb install
cd .. && rm -rf rubygems-1.3.5
ln -s /usr/bin/gem1.8 /usr/local/bin/gem
gem sources -a http://gems.github.com # add Github as a gem source, you won't