git log additions and deletions

git_changes.rb

username = '...'
commits = `git log | grep -n1 "#{username}"`.scan(/-commit ([0-9a-f]+)/).flatten
result = commits.map do |commit|
  stat = `git show #{commit} --stat -- lib`
  diff = stat[/(\d+) insertion/].to_i - stat[/(\d+) deletion/].to_i
  [commit, diff]
end

add_deletes = commits.map do |commit|
  stat = `git show #{commit} -- lib`
  add = stat.scan(/^\+([^+]|$)/).size
  del = stat.scan(/^\-([^-]|$)/).size
  [commit, add, del]
end