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Installing Ruby on Linux¶

The easiest way to install Ruby on a Linux machine is to use the Ruby Version Manager(RVM). On the terminal run the following commands:

sudo apt-get update

sudo apt-get install build-essential make curl

\curl -sSL https://get.rvm.io | bash -s stable --ruby

source ~/.rvm/scripts/rvm

Installing Ruby on Mac OS X¶

OSX comes with Ruby already installed. The version might be outdated. We can run parallel versions os Ruby using RVM.

\curl -sSL https://get.rvm.io | bash -s stable --ruby

source ~/.rvm/scripts/rvm

There is an installer available from here.

IRB is an interactive Ruby shell.

From the terminal run

irb

You can also start the irb terminal without a prompt as follows :

irb --noprompt

You can also use the simple prompt option that does not display a lot of information as follows :

irb --simple-prompt

You should now be on the IRB prompt. You can type any valid Ruby commands on the shell

irb(main):001:0> "Howdy Ruby" * 3

The output will be shown starting with the => symbol

If there's no auto-complete when you TAB in IRB shell, you can add the following line to the ~/.irbrc file.

require 'irb/completion'

Instead of using the irb terminal, you can also run ruby from scripts. Add teh following at the beginning of the file :

#!/usr/bin/env ruby

You can also add the -w to show warning as follows :

#!/usr/bin/env ruby -w

A simple hello world Ruby script can be as follows :

# helloworld.rb
#!/usr/bin/env ruby -w
puts "Hello World"

Make script file executable as follows :

chmod +x helloworld.rb

Execute the script

./helloworld.rb