Bare Metal Ruby

This manual explains how to install the most recent stable version of Ruby on Linux, without using rbenv or alternative version managers. The goal was to find a fast and reliable approach for provisioning expendable virtual machines for Rails development environment.

Basic assumptions:

Notice the

dev

package that should be installed in addition to the primary one. It is required to build native extensions for Ruby gems.

sudo apt-get install software-properties-common
sudo apt-add-repository ppa:brightbox/ruby-ng
sudo apt-get update
sudo apt-get install ruby2.6 ruby2.6-dev

Brightbox manual proposes a tool called

ruby-switch

that can help to switch between multiple Rubies on the same system. Since there will be only one of them, this step is unnecessary.

By default,

gem

will try to install new gems to the system folder (e.g.

/var/lib/gems/2.4.0

), which is no good. Ruby version managers override this path with something under user home directory. But the same operation could be done manually. To permanently set target directory to the user home, and these lines to your

~/.bashrc

:

export GEM_HOME=$HOME/.gem/ruby/2.6.0
export PATH=$HOME/.gem/ruby/2.6.0/bin:$PATH

Here is the most important thing you need to know about Ruby version managers to understand what exactly they do in system configuration:

"RubyGems' default local repository can be overridden with the

GEM_PATH

and

GEM_HOME

environment variables.

GEM_HOME

sets the default repository to install into.

GEM_PATH

allows multiple local repositories to be searched for gems" — (rubygems.org)

Log into the shell, and execute these commands to ensure

gem

and

ruby

binaries are available, gem home path is configured correctly, and native extensions could be built:

cd
gem install bundler rails
rails new testapp

Or just execute

gem env

to see the paths without installing anything.

Here is a full

Vagrantfile

to provision new Linux VM with Ruby development environment: https://github.com/dreikanter/vagrant-rails

Peace ✌️