send a USB port reset to a USB device

usbreset.py

#!/usr/bin/env python
# usbreset -- send a USB port reset to a USB device
#
# http://askubuntu.com/questions/645#answer-661
#
# $ sudo usbreset.py DUB
# Looking for device: DUB
# Executing command: `lsusb | grep DUB`
# Subprocess:  b'Bus 001 Device 006: ID 2001:1a02 D-Link Corp. DUB-E100 Fast...'
# Found device 001 on bus 006 for "D-Link Corp. DUB-E100 Fast Ethernet Adapt..."
from __future__ import print_function

import os
import re
import sys
import fcntl
import argparse
import subprocess

USBDEVFS_RESET = 21780


def main():
    command_line = argparse.ArgumentParser(description='USB device reset')

    command_line.add_argument(
        'desc', metavar='DESC',
        type=str, nargs='?', default='USB',
        help='Device description')

    options = command_line.parse_args(sys.argv[1:])

    print('Looking for device:', options.desc)

    lsusb_cmd = 'lsusb | grep {}'.format(options.desc)
    print('Executing command: `{}`'.format(lsusb_cmd))

    lsusb_out = subprocess.check_output(lsusb_cmd, shell=True)
    print('Subprocess: ', lsusb_out.strip())

    parts = re.search(r'Bus (?P<bus>\d+) Device (?P<dev>\d+): ID [:\d\w]+ (?P<desc>.*)$', str(lsusb_out))
    bus = parts.group('bus')
    dev = parts.group('dev')
    desc = parts.group('desc').strip()
    print('Found device {} on bus {} for "{}"'.format(bus, dev, desc))

    f = open('/dev/bus/usb/{}/{}'.format(bus, dev), 'w', os.O_WRONLY)
    fcntl.ioctl(f, USBDEVFS_RESET, 0)

if __name__ == '__main__':
    main()