Recover deleted S3 files from a versioned bucket

recover.rb

require 'json'

def recover_bucket(bucket)
  list = `aws s3api list-object-versions --bucket #{bucket} --output json --query 'DeleteMarkers[?IsLatest==\`true\`].[Key, VersionId]'`
  pairs = JSON.parse(list)
  pairs.each do |(key, versionId)|
    STDOUT.puts `aws s3api delete-object --bucket #{bucket} --key #{key} --version-id #{versionId}}`
  end
end

recover_bucket(ARGV[0])

I know JSON.parse(list) is memory-inefficient but if you are undeleting millions of files you don't have time to argue with me about it.