brew-log command for displaying git log of selected Homebrew formulae

brew-log.rb

#!/usr/bin/env ruby -wKU

if ARGV.empty?
  puts "Usage: #{File.basename $0} <names>"
  exit(2)
else
  dir = `brew --prefix`.chomp
  exec 'git', "--git-dir=#{dir}/.git", 'log', '--', *ARGV.map { |name|
    "Library/Formula/#{name}.rb"
  }
end