We will be installing rbenv and ruby-build from our own fork Show archive.org snapshot , not from the Ubuntu sources.

Installing rbenv

1. Install rbenv Show archive.org snapshot :

   git clone https://github.com/rbenv/rbenv.git ~/.rbenv
   

   For Bash:

   echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
   echo 'eval "$(rbenv init -)"' >> ~/.bashrc
   

   For ZSH:

   echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc
   echo 'eval "$(rbenv init -)"' >> ~/.zshrc
   

   Now reinitialize your shell, e.g. by opening a new terminal. Running type rbenv should then say "rbenv is a function".

2. Install ruby-build Show archive.org snapshot (gives you rbenv install):

   git clone -b local-openssl-for-old-rubies https://github.com/makandra/ruby-build.git ~/.rbenv/plugins/ruby-build
   

   You should now be able to say rbenv install --list, and see quite a few rubies.

3. Install rbenv-aliases Show archive.org snapshot (allows you to leave out patch levels):

   git clone https://github.com/tpope/rbenv-aliases.git ~/.rbenv/plugins/rbenv-aliases
   rbenv alias --auto
   

4. Install rbenv-default-gems Show archive.org snapshot (set it up to automatically install bundler):

   git clone https://github.com/rbenv/rbenv-default-gems.git ~/.rbenv/plugins/rbenv-default-gems
   

Then you can install the required ruby versions:

Install build dependencies. Do this before installing any Rubies via rbenv or you may have to reinstall them Show archive.org snapshot .

apt-get install autoconf bison build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev

Some things that will be helpful when using rbenv:

• Read our basic introduction to rbenv
• Every time you notice a message like rbenv: version '2.5.5' is not installed, alias this version to your existing Ruby version e.g. rbenv alias 2.5.5 2.5 (will alias 2.5.5 to the most recent installed version of Ruby 2.5)
• There are different ways to switch Ruby versions on rbenv. You should know about them.
• To make your ruby-build aware of new Ruby versions some time later, you need to update the plugin's git directory.
• To install old versions of REE, you need to tweak some files.