The reset is triggered by one of the control lines, which the Arduino IDE toggles when it opens the pot. It's possible to open the port without doing that in which case you'll receive subsequent output but won't reset the board. You may be able to find a client that already does that (PuTTY?) but if you don't find one, it's relatively simple to write your own client that just reads from a serial port and spews everything it reads out on stdout.