ComputerCraft Turtle default /startup script.

--[[
  Turtle modem initialization.
]]

local function openModem()
  local sSide = "right";
  if peripheral.getType(sSide) == "modem" then
    if rednet.isOpen(sSide) then
      return true;
    else
      rednet.open(sSide);
      if rednet.isOpen(sSide) then
        return true;
      end
    end
  end

  return false
end

if turtle then
  if openModem() then
    print("Internal modem active.")
  end
  print("Unit " .. os.getComputerID() .. " reporting for duty.");
end