1.code.rb

t = Thread.start{
  begin
    puts "starting executing code!"
    sleep 1
    puts "done executing code!" # we don't expect to reach here
  rescue Exception
    puts "rescuing!"            # we don't expect to reach here
  ensure
    puts "ensuring!"            # will we reach here????? (yes)
  end
}
t.kill
t.join
puts "done!"

2.output.txt

➔ ruby ../thing.rb
ensuring!
done!