pty.rb

   # Using PTY instead of IO.popen, see answer:
   # http://stackoverflow.com/questions/1154846/continuously-read-from-stdout-of-external-process-in-ruby
   def spawn_command(command)
      begin
         PTY.spawn(command) do |stdin, stdout, pid|
            Process.wait(pid)
            begin
               stdin.each { |line| message "       #{line}" }
            rescue Errno::EIO
               # child process stopped giving input
            end
         end
         return $?.exitstatus
      rescue PTY::ChildExited => e
         return e.status
      # child process exited
      end
   end