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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:

Update the packages

sudo apt-get update

Install tools for development

sudo apt-get install build-essential make curl

Install RVM and current version of Ruby

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

Reload the configs before start using RVM

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 The version might be outdated.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.

Install RVM and latest Ruby version

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

Realod the RVM config

source ~/.rvm/scripts/rvm

Installing Ruby on Windows

There is an installer available from here.

Interactive Ruby Shell

IRB is an interactive Ruby shell.

Lanuch IRB

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

Setting Up AutoCompletion from IRB

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'

Running Ruby scripts

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