arduino_rtc.py

#!/usr/bin/env python

import serial
import atexit
from datetime import datetime

ser = serial.Serial('/dev/tty.usbmodem1411', 9600)

while True:

    current_time = ser.readline().decode('utf-8')
    print(datetime.utcfromtimestamp(int(current_time)))

rtc1.ino

#include <Wire.h>
#include "RTClib.h"

RTC_DS1307 rtc;



void setup () {
    // for Leonardo/Micro/Zero
    while (!Serial);

    Serial.begin(9600);
    if (! rtc.begin()) {
        Serial.println("Couldn't find RTC");
        while (1);
    }
    
}

void loop () {
  
    DateTime now = rtc.now();
    
    Serial.println(now.unixtime());
    delay(1000);
}