Print out Git stats on a repo using Ruby

rstat.rb

#!/usr/bin/ruby

require 'yaml'
contributions = {}
`git log --shortstat -z`.each("\0") do |commit|

  commit.match(/Author: (\w+) /)
  author = $1

  commit.match(/(\d+) files changed, (\d+) insertions\(\+\), (\d+) deletions\(\-\)/)

  contributions[author] ||= Hash.new(0)

  contributions[author]['commits']    += 1
  contributions[author]['files']      += $1.to_i
  contributions[author]['insertions'] += $2.to_i
  contributions[author]['deletions']  += $3.to_i
end

contributions[:total] = contributions.values.inject(Hash.new(0)) { |sum, elt| elt.keys.each { |k| sum[k] += elt[k] }; sum }

percentages = {}
contributions.keys.each { |name|
   next if :total == name
   percentages[name] ||= {}
   %w{commits files insertions deletions}.each { |field|
      percentages[name][field] = "%.1f%%" % (100.0 * contributions[name][field] / contributions[:total][field])
   }
}

puts percentages.to_yaml