Ruby Introduction

What is Ruby?

• Ruby is an open source language that can be used for web development.
• It is a high level language which means its readable just like english language.
• It is interpreted and so it does not need a compiler to run.
• Object oriented language which helps users to manipulate data structures called object in order to build and execute data.
• Scripting language designed by Matz.

How to declare a variable?

Just declare a variable by assigning a value to it and your done.
eg: my_num = 25
You can reassign it. For boolean variables just assign true or false. For string variables assign value within quotes.
eg: my_boolean = true
      my_string = "Ruby"

What are the arithmetic operators in Ruby?

Mainly there are 6 operators in use:+, -, *, /, **(exponentiation),  %(modulo)
Exponentiation means raising one number to the power of the other. eg: 2**2 = 4
Modulo means the remainder of division eg: 25%7 = 3

What are the methods are used to display text?

print "ruby"
puts "ruby" - adds a new line after output.

Comments begin with # . => in the comment indicates the vale retuned by the commented code.
eg: 1.class # => Fixnum: the number 1 is a Fixnum

Now lets start practicing ruby on our terminal:
To have an interactive ruby in terminal type the command after $ sign: $irb

Here you can type in ruby for eg:

$puts 2+3

Output: 4

=>nil

$quit() (to quit interactive ruby)

You can open a text editor from terminal:

nano helloworld.rb

This opens an editor and you can type program like below

print(1+2)

print(“\n”)

puts “Hello world”

control+o = Save file

control+x = Exit file

ruby helloworld.rb (command to run a program)

Hurrah! Its that cool.

Source: http://www.codecademy.com/
http://www.tutorialspoint.com/
O'reilly Ruby programming language