list contributors to a Git repository

gistfile1.rb

require 'rugged'

repo = Rugged::Repository.new('.')
walker = Rugged::Walker.new(repo)
walker.push('refs/heads/gh-pages')

emails = walker.map do |commit|
  commit.author[:email]
end

emails.reject! do |email|
  email.end_with?('@users.noreply.github.com')
end

puts emails.uniq!.sort!

One-liner from @aroben:

git log --format=%ae BRANCH | grep -v '@users\.noreply\.github\.com' | sort -u

https://twitter.com/aroben/status/543547456076926976?cn=cmVwbHk%3D