devpuppy

# http://andora.us/blog/2011/03/03/choosing-foreground-using-luminosity-contrast-ratio/
# color contrast ratio ranges from 1 (least) to 21 (most, white/black)
class Color
  attr_reader :r, :g, :b

  def initialize(hex)
    raise 'Invalid hex code' unless hex =~ /[0-9a-f]{6}/i
    hexes = hex.scan /.{2}/
    @r,@g,@b = hexes.map { |h| h.hex.to_i }
  end

gcatlin

brew update
brew versions FORMULA
cd `brew --prefix`
git checkout HASH Library/Formula/FORMULA.rb  # use output of "brew versions"
brew install FORMULA
brew switch FORMULA VERSION
git checkout -- Library/Formula/FORMULA.rb    # reset formula

## Example: Using Subversion 1.6.17
#