#!/usr/bin/python

from sys import argv
import time, datetime

if __name__ == '__main__':

    if len(argv) < 2:
        print("Usage: sumofdays.py [ space separated list of dates in day.month.year format ]\
        \nExample: sumofdays.py \"26.08.1986 31.05.1988 01.06.1988 10.01.1990 18.02.1991 13.07.1992 01.08.1992 31.01.1993 16.03.1993 04.05.1993 21.05.1993 10.10.1993 23.10.1993 01.08.1994 05.08.1994 19.03.1995 28.12.1997 30.12.1997\"")
        exit(0)

    time_format = "%d.%m.%Y"

    dates=[]
    datesstring = argv[1]
    listofdatestrings = datesstring.split(" ")

    for date_string in listofdatestrings:
        dates.append(datetime.datetime.fromtimestamp(time.mktime(time.strptime(date_string, time_format))))


    id = len(dates)-1
    sum = datetime.timedelta(0)

    while( id > 0 ):
        sum += dates[id] - dates[id-1]
        id -= 2

    print(sum)

#!/bin/sh

export LC_TIME="C"

# week day
WDAY="$1"

#month day
MDAY="$2"

#month
MONTH="$3"

#time HH:MM
TIME="$4"

# year (current if empty)
YEAR="$5"

# get current year
YEAR=`date -d "$WDAY $MONTH $MDAY $TIME $YEAR" | awk '{print $NF}'`

# get real week day for current year
RWDAY=`date -d "$WDAY $MONTH $MDAY $TIME $YEAR" | awk '{print $1}'`

# looking for year suitable for requested date
while [ "$WDAY" != "$RWDAY" ]; do
	YEAR=$(($YEAR - 1))
	RWDAY=`date -d "$WDAY $MONTH $MDAY $TIME $YEAR" | awk '{print $1}'`
done

echo    "$WDAY $MONTH $MDAY $TIME $YEAR" 
date -d "$WDAY $MONTH $MDAY $TIME $YEAR" '+%s'

./lookdate Fri 13 Sep 11:00
Fri Sep 13 11:00 2002
1031904000

./lookdate Fri 13 Sep 11:00 2001
Fri Sep 13 11:00 1996
842601600