Hello World program in Ruby language

Writing a Hello World program in Ruby is as simple as writing a single line in a file as

puts 'Hello World'

Run the Ruby program

Create a file name as hello.rb in your favorite editor or through command line editor like vim.

Although, you can give any name to file. I have used hello. By convention, Ruby source files have .rb file extension.

Then, type following line in the file:

puts 'Hello World' # or puts "Hello World"

Run the program in the terminal or shell as:

ruby hello.rb

You should be able to see output as:

Hello World

Congrats! You just wrote your first program in Ruby.

Evaluate yourself

Key points to understand

• File extension of Ruby program is .rb, or .rbw
  • The .rbw extension is used for “windowed” applications.
• To print strings into the standard output (i.e terminal), you can use puts, which means “put string”.
• # is used as a comment mark.
  • This does not have to be at the beginning of a line.
  • This can be used on the same line after a Ruby statement.
• =begin is the start of a mult-line comment.
• =end is the closing of a mult-line comment.