.rb

What is a .rb file?

RB is a Ruby source file — the language behind Ruby on Rails, known for its elegant, developer-friendly syntax.

Use caution
Type Code
By Yukihiro Matsumoto
MIME application/x-ruby

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What is it

You have a .rb file — Ruby source code. Ruby is the language behind Ruby on Rails, the web framework that taught the world that building web applications didn't have to be painful. GitHub, Shopify, Basecamp, Airbnb (early versions), and countless startups were built on Rails.

Yukihiro "Matz" Matsumoto created Ruby in 1995 with an explicit goal: programmer happiness. The language reads almost like English, has elegant syntax for blocks and iterators, and treats everything as an object (including numbers and nil). Ruby's philosophy is that there should be a beautiful way to express every idea. This made it a joy to write and, combined with Rails' "convention over configuration" approach, created a productivity boom in web development during the late 2000s.

Any text editor opens .rb files. VS Code with the Ruby extension provides syntax highlighting and debugging. RubyMine (JetBrains, paid) is the full-featured IDE. To run Ruby: install it from ruby-lang.org (or use rbenv/rvm for version management), then `ruby file.rb`. For Rails projects: `gem install rails && rails new myapp`.

Technical details
Full Name
Ruby Script
MIME Type
application/x-ruby
Developer
Yukihiro Matsumoto
Magic Bytes
N/A
Safety
.rb requires caution. Script files can execute arbitrary code. Only run from trusted sources.
What opens it
Any text editor
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VS Code
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RubyMine
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FAQ
Is Ruby still relevant?
Yes — Ruby on Rails remains a productive and popular web framework. Shopify, GitHub, and Basecamp are all Rails applications. The ecosystem is mature, well-documented, and actively maintained. New alternatives exist (Next.js, Django), but Rails is far from obsolete.
What's the difference between Ruby and Python?
Both are dynamic, interpreted languages with clean syntax. Ruby emphasises expressiveness and 'programmer happiness.' Python emphasises readability and has a larger ecosystem for data science and ML. For web development, both have strong frameworks (Rails vs Django).
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