As of 14.04 Ubuntu no longer has ffmpeg in its default repositories. If you want to install it you'll have to add a new repo first.

sudo add-apt-repository ppa:mc3man/trusty-media

sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install ffmpeg

Step 1: Install Ubuntu

Step 2: Add a deploy user and optionally a user for yourself.

Assuming you're logged in as root add these users and login as "not root."

adduser deploy
adduser [yourname] #optionally
vim /etc/group
# add your users to the sudo group like so: 
  sudo:x:27:isaac,deploy
vim /etc/ssh/sshd_config
# add to file or if they exist set the flags to no.

1. Create your gem:

Here is the most modern approach to gem crafting:

bundle gem gemname
cd gemname

edit your_gem.gemspec and add description, summary, required gems and optional website. Add required gems for development such as rspec, rails or minitest to the Gemfile.

2. Add testing framework:

RSpec:

rspec --init
touch spec/your_gem_spec.rb

Minitest:

# Rakefile

Very little has changed since Mavericks but here's an updated tutorial.

Step 1: Install XCode Command Line Tools

xcode-select --install

Step 2: Install and prepare Homebrew

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew doctor
brew update

Step 3: Install rbenv

brew install rbenv ruby-build openssl

Many long term users of Macvim like myself have been annoyed that fullscreen mode cuts off the first couple lines and shows a bar on the right when using OSX Yosemite. After trying out multiple forks that kind of fixed it but also introduced other problems I finally found a satisfactory fix. Just run this in the terminal to turn off yosemites fullscreen method on macvim.

$ defaults write org.vim.MacVim MMNativeFullScreen 0