Australia Post tracking number extractor

barcode.py

#!/usr/bin/python3

# Converts the 56 digits 2D Australia Post barcode to the 22 digits tracking number.
# Reads from stdin until newline, and copies the tracking number to the clipboard.
# Other characters then digits are removed.
#
# Needs Python3 and the clipboard library. Install from the command line like this:
#   pip3 install clipboard
# Then save this file as barcode.py and start the script like this:
#   python barcode.py
#
# test input:
#   01990000000000000003070045678901234567898000000000000000
# output:
#   tracking code 0307004567890123456789 copied to clipboard
#
# tested in Windows and Linux

import clipboard
import sys

for line in sys.stdin:
    digits = "".join(filter(str.isdigit, line))
    if len(digits) == 56:
        tracking = digits[18:40]
        clipboard.copy(tracking)
        print("tracking code " + tracking + " copied to clipboard")
    else:
        print("wrong length: %d" % (len(digits)))