bd.py

#! /usr/bin/env python

import sys
from datetime import datetime

arguments = sys.argv
arg_date = arguments[1]

bd = datetime.strptime(arg_date, "%Y%m%d")
now = datetime.now()  
diff = now - bd

delta = diff.days / 365.2425
age = int(delta)
month = int((delta - age) * 12)

nextbirthday = bd.replace(year=(now.year + 1))
nextdelta = nextbirthday - now
nextdiff = nextdelta.days + 1

if nextdiff > 365.2425:
    nextbirthday = bd.replace(year=(now.year), month=bd.month)
    nextdelta = nextbirthday - now
    nextdiff = nextdelta.days + 1
    
print "You are " + str(age) + " years old and " + str(month)  + " months."
print "Next Birthday is after " + str(nextdiff)  + " days."