Resources

Ruby

• RubyDoc - the official documentation for Ruby, not very intuitive
• OmniRef - comprehensive Ruby core and library search, no browse
• Ruby Cheat Sheet - one page with a list of all the methods you might want to use
• RubyDoc.info - documentation for any Ruby gem you can think of
• Ruby Toolbox - find gems that will meet your needs
• Ruby Style Guide - how to format your Ruby code
• Ruby Monk - interactive tutorials
• Ruby Koans - exercises to expand your mind
• Ruby Warrior - learn Ruby by playing a really fun game
• Learn Ruby the Hard Way - in-depth book about Ruby
• RegexOne - learn regular expressions if you dare

Command line

• CLI Crash Course - Zed Shaw's introduction to the command line
• Michael Byrd's Command Line flash cards

Git

• The Git website - lots of videos and resources to learn git
• Git Immersion - Git exercises
• Pro Git - free book on using Git
• GitHub Bootcamp - series of articles on basic GitHub use
• GitHub Guides - series of guides on further GitHub use

HTML

CSS

JavaScript

• Mozilla Developer Network - JavaScript - documentation for JavaScript
• Code Combat - Learn JavaScript by playing a game

Rails

• Rails Documentation - the official documentation for Rails
• Learn Ruby on Rails
• Michael Hartl's Ruby on Rails Tutorial
• Rails for Zombies