host.rb

#!/usr/bin/env ruby
require 'rubygems'
require 'ruby-debug'

pid = fork do
  $stderr.reopen(File.open("/dev/null", "w"))
  exec("lftp -c 'sleep 100000'")
end

puts "forked with #{pid}\n"
Process.detach(pid)
Process.kill("TERM", pid)
puts `ps aux | grep lftp`