import serial, time, sys, threading, datetime, shutil

def stream_serial():
    #stream data directly from the serial port
    line = ser.readline()
    line_str = str(line)
    print line_str


# configure the serial connections
global ser, BAUDRATE
comnum = '/dev/ttyUSB1'
ser = serial.Serial()
ser.baudrate = 4800
ser.port = comnum
ser.timeout = 2
ser.open()
ser.isOpen()

#Prints menu and asks for input
global lat_input, long_input

while 1:
    line = ser.readline()
    line_str = str(line)
    #print line_str
    if(line_str[4] == 'G'): # $GPGGA
        if(len(line_str) > 20):
            print(line_str)
        # open txt file and log data
            f = open('nmea.txt', 'a')
            try:
                f.write('{0:}'.format(line_str))
            finally:
                f.close()
        else:
            stream_serial()
    #time.sleep(0.2)