Run a block of code as another user in Ruby. You could use it to unsudo a sudoed script.

as_user.rb

#!/usr/bin/env ruby
require 'etc'
 
def as_user(user = Etc.getlogin, &block)
  u = (user.is_a? Integer) ? Etc.getpwuid(user) : Etc.getpwnam(user)
  puts "Running child process as the user #{user}(#{u.uid})."
  pid = Process.fork do
    Process.uid = u.uid
    block.call(user)
  end
  print "Waiting for the process #{pid} to finish...\r"
  Process.wait(pid)
  puts "The process #{pid} has finished.             "
end

# Run block as the sudoer (unsudo).
as_user do
  system("sleep 3")
end

# Run block as another user.
as_user "OtherUser" do
  system("sleep 3")
end