Install Ruby on Rails with rbenv

Ubuntu prerequisites

Update and install dependencies in ubuntu

sudo apt-get update
sudo apt-get install autoconf bison build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev libgdbm3 libgdbm-dev

Install rbenv

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

From here, you should add ~/.rbenv/bin to your $PATH so that you can use rbenv’s command line utility. Also adding ~/.rbenv/bin/rbenv init to your ~/.bash_profile will let you load rbenv automatically.

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

Next, source rbenv by typing:

source ~/.bashrc

You can check to see if rbenv was set up properly by using the type command, which will display more information about rbenv:

type rbenv

Your terminal window should output the following:

rbenv is a function
...

In order to use the rbenv install command, which simplifies the installation process for new versions of Ruby, you should install ruby-build, which we will install as a plugin for rbenv through git:

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build

Arch Linux

yaourt -S rbenv ruby-build

At this point, you should have both rbenv and ruby-build installed, and we can move on to installing Ruby.

Install Ruby

With the ruby-build rbenv plugin now installed, we can install whatever versions of Ruby that we may need through a simple command. First, let’s list all the available versions of Ruby:

rbenv install -l

The output of that command should be a long list of versions that you can choose to install.

We’ll now install a particular version of Ruby. It’s important to keep in mind that installing Ruby can be a lengthy process, so be prepared for the installation to take some time to complete.

As an example here, let’s install Ruby version 2.3.1, and once it’s done installing, we can set it as our default version with the global sub-command:

rbenv install 2.5.1
rbenv global 2.5.1 # for a global install
rbenv local 2.5.1 # for a project install

If you would like to install and use a different version, simply run the rbenv commands with a different version number, as in rbenv install 2.3.0 and rbenv global 2.3.0.

Verify that Ruby was properly installed by checking your version number:

ruby -v

If you installed version 2.3.1 of Ruby, your output to the above command should look something like this:

ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-linux]

You now have at least one version of Ruby installed and have set your default Ruby version. Next, we will set up gems and Rails.

Working with Gems

Gems are packages that extend the functionality of Ruby. We will want to install Rails through the gem command.

So that the process of installing Rails is less lengthy, we will turn off local documentation for each gem we install. We will also install the bundler gem to manage application dependencies:

echo "gem: --no-document" > ~/.gemrc
gem install bundler

Update rbenv

cd ~/.rbenv
git pull
cd plugins/ruby-build
git pull