converts a date into an ANSI number

date2ansi.py

#!/usr/bin/env python

import sys

from datetime import datetime, timedelta, date, time

# ANSI constant
ANSI_DATE_START = datetime(1601, 1, 1)

if (len(sys.argv) <> 2):
        print 'Usage: date2ansi.py [date, e.g. 2013-06-26]'
else:
        coverage_date = sys.argv[1]
        coverage_date = datetime.strptime(coverage_date, "%Y-%m-%d")
        diff = coverage_date - ANSI_DATE_START
        print diff.days