Your first Ruby script

Hello file.rb

A Ruby script is a plain text file with the rb extension. Open any text editor, type the line below, and save it as hello.rb in your working folder.

puts "Hello, Ruby"

That single line is a complete program. The next section explains what puts does with the string you hand it.

puts prints

puts prints text to the terminal and moves to a new line afterwards, so each call starts on a fresh line. Its sibling print writes without that final newline.

puts "one" puts "two"

one
two

ruby file.rb

Run the file by passing its name to the ruby command. The interpreter reads hello.rb from top to bottom and prints the result:

Run the script

ruby hello.rb

Hello, Ruby

The terminal prints Hello, Ruby and nothing else. No server and no browser are needed for plain scripts like this one.

Common beginner mistakes

Three mistakes catch almost every beginner. First, typing only the file name runs nothing: the ruby command must come first, as in ruby hello.rb.

Second, a typo such as put instead of puts calls a method that does not exist. Third, an unclosed quote swallows the rest of the line, so close each string on the same line you open it:

puts "Quotes come in pairs: open and close on one line"

Next: Variables

Article author: Arthur Isaev