Comments are programmer-readable annotations that are ignored at runtime. Their purpose is to make source code easier to understand.

Single line comments

The # character is used to add single line comments.

#!/usr/bin/ruby -w
# This is a single line comment.
puts "Hello World!"

When executed, the above program will output Hello World!

Multiline comments

Multiple-line comments can be added by using =begin and =end syntax (also known as the comment block markers) as follows:

#!/usr/bin/ruby -w
=begin
This is a multiline comment.
Write as many line as you want. 
=end
puts "Hello World!"

When executed, the above program will output Hello World!