trippy.rb

c = LXC::Container.new('foo')
c.create('ubuntu')
c.start
# we'll start tripping from here
reader, writer = IO.pipe

c.attach(wait: true) do
  reader.close # its a process clone, so you have all the variable
  x = Dir['/*']
  writer.write(Marshal.dump(x))
end

writer.close
x = Marshal.load(reader.read)
reader.close