step.rb

#!/usr/bin/env ruby

master_commits = []
`git log --oneline --reverse master`.split("\n").each do |commit|
  master_commits << commit[0..6]
end

presenting_commits = []
`git log --oneline --reverse presenting`.split("\n").each do |commit|
  presenting_commits << commit[0..6]
end

latest = master_commits[presenting_commits.size]

unless latest.nil?
  `git cherry-pick #{latest}`
  puts `git show #{latest}`
else
  puts 'Demo over!'
end