01_install_ruby

Install Ruby

In this tutorial I will show you how to install Ruby in your machine.

Installation in Ubuntu 18.04

I have chosen Ubuntu 18.04 because is a popular OS for developers and also for deployments. If you do not have this OS or you just want to play, you can use Vagrant with this Vagrantfile as a sandbox to learn.

Even though there are many ways to install Ruby in Ubuntu, I prefer using the rbenv Ruby version manager tool. We will install this tool and then a version of a Ruby interpreter to be able to program in this language.

1. Install Ubuntu dependences

$ sudo apt-get install git gcc make libssl-dev libreadline-dev zlib1g-dev

2. Install rbenv from git repository

To install rbenv you just need to follow the instructions described in rbenv README file. The steps needed are described below:

2.1 Clone rbenv into ~/.rbenv.

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

Optionally, try to compile dynamic bash extension to speed up rbenv. Don't worry if it fails; rbenv will still work normally:

$ cd ~/.rbenv && src/configure && make -C src

2.2. Add ~/.rbenv/bin to your $PATH for access to the rbenv command-line utility.

$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc

2.3. Run ~/.rbenv/bin/rbenv init and follow the instructions to set up rbenv integration with your shell. This is the step that will make running ruby "see" the Ruby version that you choose with rbenv. In this case the instructions are to add this line at the end of the .bashrc file:

eval "$(rbenv init -)"

2.4. Restart your shell so that PATH changes take effect. (Opening a new terminal tab will usually do it.)

2.5. Verify that rbenv is properly set up using this rbenv-doctor script:

$ curl -fsSL https://github.com/rbenv/rbenv-installer/raw/master/bin/rbenv-doctor | bash
Checking for `rbenv' in PATH: /usr/local/bin/rbenv
Checking for rbenv shims in PATH: OK
Checking `rbenv install' support: /usr/local/bin/rbenv-install (ruby-build 20170523)
Counting installed Ruby versions: none
  There aren't any Ruby versions installed under `~/.rbenv/versions'.
  You can install Ruby versions like so: rbenv install 2.2.4
Checking RubyGems settings: OK
Auditing installed plugins: OK

2.6. Install ruby-build, which provides the rbenv install command that simplifies the process of installing new Ruby versions.

$ git clone https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build

3. Install Ruby 2.5.3

To see all the available Ruby versions for the Rbenv tool you can run this command:

$ rbenv install -l

In this tutorial I have decided to install Ruby 2.5.3 because is the latest stable version. To install this version, just run the following command:

$ rbenv install 2.5.3

This will take a while to download and compile.

4. Set Ruby 2.5.3 as our default interpreter

To use locally and globally the downloaded Ruby version, you just need to run this commands:

$ rbenv local 2.5.3
$ rbenv global 2.5.3

You can test if the correct Ruby is being used by running:

$ ruby -v

And voilà, you have Ruby installed in your system.

BONUS: Install and use another Ruby version

You can install another Ruby version using the commands shown above. Then you can list all installed Ruby versions by the command:

$ rbenv versions

Swith from one version to other and check it works by typing:

$ rbenv local [VERSION]
$ rbenv global [VERSION]
$ ruby -v