Hello World

Write a file

Save this as hello.rb.

puts "Hello, World!"

Run it

Pass the filename to the Ruby interpreter.

ruby hello.rb

Print several values

puts adds a newline. print does not.

language = "Ruby"
puts "Learning", language
print "No newline"
puts " yet"

First habits

• Ruby files use the .rb extension
• Method calls often omit parentheses for simple cases
• Everything is an object, including numbers and strings
• Use IRB to experiment before saving a file