publicprinter.py

import serial
import time

DEVICE_PATH = '/dev/ttyACM0'
BAUD_RATE = 115200


s = serial.Serial(DEVICE_PATH, BAUD_RATE)
while True:
    if s.in_waiting > 0:  # when new serial info is waiting
        cmd = s.read(1)
        if cmd == b'p':
            # keep old file, print new file
        elif cmd == b'd'
            # delete last file
        else:
            print('Unknown serial command: {!r}'.format(cmd))
    time.sleep(0.5)