wrapper.rb

require 'pty'
STDOUT.sync = true

PTY.spawn('./bin/openttd -D -c config.cfg') do |stdin, stdout, pid|
  threads = []
  threads << Thread.new { 
    stdin.each {|line| puts "SERVER: #{line}"}
  }

  threads << Thread.new {
    while (command = gets.chomp)
      puts "CLIENT: #{command}"
      stdout.puts command
    end
  }
  threads.each(&:join)
end