When switching between multiple Ruby applications, rbenv makes it easy to find, install, and use the appropriate version for the project. Let’s take a look at how it is used.

Install

Upgrade or install ruby-build:

brew upgrade ruby-build # or `install` if ruby-build is not already installed

Add-Ons

The plugin rbenv-bundler makes it possible to not have to type bundle exec in front of every command. This can be installed with brew install rbenv-bundler.

Check Local Versions

Run rbenv versions to see available Ruby versions, and rbenv version to see the current version being used.

Check Installable Versions

rbenv install --list to list all installable versions. Rails requires version 2.2.2 or greater per the Rails Guides at the time of publication. Let’s install version 2.5.5.

Install A Ruby

rbenv install 2.5.5

Use The Ruby

Let’s make sure our Rails application is using 2.5.5 by specifying that version in the .ruby-version file in the application root directory of our Ruby project.

Now when we cd into the application root directory, and type ruby -v, we expect to see 2.5.5 as rbenv and other version managers have adopted the convention of looking for this file. Rails 5.2 officially supports this convention 1.

  1. Rails 5.2 sets Ruby version in Gemfile and adds .ruby-version file by default ↩