Getting started with Ruby Language
Ruby is a multi-platform open-source, dynamic object-oriented interpreted language, designed to be simplistic and productive. It was created by Yukihiro Matsumoto (Matz) in 1995.
According to its creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, and Lisp. It supports multiple programming paradigms, including functional, object-oriented, and imperative. It also has a dynamic type system and automatic memory management.
This example assumes Ruby is installed.
Place the following in a file named
From the command line, type the following command to execute the Ruby code from the source file:
This should output:
The output will be immediately displayed to the console. Ruby source files don't need to be compiled before being executed. The Ruby interpreter compiles and executes the Ruby file at runtime.
Hello World as a Self-Executable File—using Shebang (Unix-like operating systems only)
You can add an interpreter directive (shebang) to your script. Create a file called
hello_world.rb which contains:
Give the script executable permissions. Here's how to do that in Unix:
Now you do not need to call the Ruby interpreter explicitly to run your script.
Hello World from IRB
Alternatively, you can use the Interactive Ruby Shell (IRB) to immediately execute the Ruby statements you previously wrote in the Ruby file.
Start an IRB session by typing:
Then enter the following command:
This results in the following console output (including newline):
If you don't want to start a new line, you can use
Hello World with tk
Tk is the standard graphical user interface (GUI) for Ruby. It provides a cross-platform GUI for Ruby programs.
Step by Step explanation:
Load the tk package.
Define a widget with the title
Start the main loop and display the widget.
Hello World without source files
Run the command below in a shell after installing Ruby. This shows how you can execute simple Ruby programs without creating a Ruby file:
You can also feed a Ruby program to the interpreter's standard input. One way to do that is to use a here document in your shell command:
My First Method
Create a new file named
Place the following code inside the file:
Now, from a command line, execute the following:
The output should be:
defis a keyword that tells us that we're
def-ining a method - in this case,
hello_worldis the name of our method.
puts "Hello world!"
puts(or pipes to the console) the string
endis a keyword that signifies we're ending our definition of the
- as the
hello_worldmethod doesn't accept any arguments, you can omit the parenthesis by invoking the method