Create serial ports with Python

serial_ports.py

#!/usr/bin/env python3 -OO

import itertools
import serial
import shlex
import subprocess

MESSAGE = """
Hi there! You have a serial port:

RX = {0}
TX = {1}

You can create symbolic links to those files in /dev, naming them ttySX, where
X is a number of your choosing. Making symbolic links will have them show up
as available serial ports in applications that can only use those files. Once
you have that, you can write and read to TX and RX, respectively.

Example links:

    ln -s {0} /dev/ttyS98 # RX
    ln -s {1} /dev/ttyS99 # TX

On my side, you can use the prompt below to write to my serial port. You can
also use an application like screen to view the data I would be recieving.

My port details:

RX = {2}
TX = {3}

Example screen command:

    screen {2} 115200

Important: press ^D to quit
"""


def create_serial_pins():
    command = 'socat -d -d pty,raw,echo=1 pty,raw,echo=1'
    process = subprocess.Popen(shlex.split(command),
                               universal_newlines=True,
                               stderr=subprocess.PIPE)
    yield tuple([process.stderr.readline().split().pop() for i in range(2)])
    process.terminate()


def create_serial_line(pins=1):
    pin_pairs = [create_serial_pins() for i in range(pins)]
    return itertools.zip_longest(*pin_pairs)

for pins in create_serial_line(2):
    a = (pins[0][0], pins[1][0])
    b = (pins[1][1], pins[0][1])
    print(MESSAGE.strip().format(*itertools.chain(a, b)))
    try:
        s = serial.Serial(b[1])
        while True:
            s.write(bytes(input('>>> '), 'UTF-8'))
    except (EOFError, KeyboardInterrupt, TypeError) as err:
        print('')
        print(err)