chat

while true do
  rednet.open("back")
  shell.run("clear")
  print("What do I say? (\"exit\" to quit)")
  input = read()
  if input == "exit" then break end
  if input:len() == 0 then
    shell.run("clear")
    print("Invalid message!")
    sleep(2)
  else
    rednet.send(398 ,input)
    shell.run("clear")
    print("Sent "..input)
  end
end