# ruby
    cd ~/rn
    wget ftp://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.1-p0.tar.gz
    tar -xzvf ruby-1.9.1-p0.tar.gz
    cd ~/rn/ruby-1.9.1-p0
    ./configure
    make
    make test
    sudo make install
    # zlib
    cd ~/rn/ruby-1.9.1-p0/ext/zlib
    sudo apt-get install zlib1g-dev
    ruby extconf.rb --with-zlib-include=/usr/include --with-zlib-lib=/usr/lib
    make
    sudo make install
    # gem
    cd ~/rn
    wget http://rubyforge.org/frs/download.php/45905/rubygems-1.3.1.tgz
    tar -xzvf rubygems-1.3.1.tgz
    cd rubygems-1.3.1
    sudo ruby setup.rb
    # fix ruby executable
    cd ~/rn/ruby-1.9.1-p0
    sudo make install