Installing Prerequisites

Before installing Ruby we need to install the prerequisites or dependencies packages.

Ubuntu

Go through with following commands to install curl and setup package repositories in your terminal:

sudo apt install curl
curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list

Now, install the dependencies required for the proper development of Ruby on Rails application:

sudo apt-get update
sudo apt-get install git-core zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev software-properties-common libffi-dev nodejs yarn

macOS

Unlike Ubuntu, macOS has all the pre-requisite packages installed when you install Xcode. If you find any error related to these packages, consider reinstalling Xcode via following command:

xcode-select --install

Installing Ruby

Check Getting started with Ruby page to install Ruby as per the Operating System you have.

Verify the installation by running following command:

$ ruby -v
ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-darwin19]

NOTE: You might have different version depending on your OS and Ruby version.

Install bundler

Install the bundler which manages Ruby gems (or packages as in other languages).

$ gem install bundler

Installing Ruby on Rails

Run the following command in your Terminal to install latest version of Rails.

gem install rails

For specific version installation, specify the version as follows:

gem install rails -v 6.0.2.2

And we verify installation of Rails as:

rails -v
# Rails 6.0.3.3