ts.py

#!/usr/bin/env python
#
# Simple timeshift script
#

import re
import sys
import time
import operator

def shift_time(op, value, measure):
    # Create operator map, to avoid some if/else's
    op_map = {'+' : operator.add, '-' : operator.sub}
    multiplier = 1

    if measure == 'm':
        multiplier = 60
    elif measure == 'h':
        multiplier = 60*60
    elif measure == 'd':
        multiplier = (60*60)*24
    elif measure == 'w':
        multiplier = ((60*60)*24)*7
    elif measure == 'M':
        multiplier = ((60*60)*24)*30 # egh..
    elif measure == 'y':
        multiplier = ((60*60)*24)*365

    # Convert our value + measure to seconds
    seconds = multiplier * int(value)
    current_ts = int(time.time())

    return op_map[op](current_ts, seconds)

def usage():
    print "Usage: ./ts.py +|-VALUE[mhdwMy]"
    sys.exit(1)

def main():
    if len(sys.argv) < 2:
        usage()

    time_input = sys.argv[1]

    pattern = '(\+|\-)(\d+)([smhdMy])|now'
    match = re.match(pattern, time_input)


    if match is not None:
        if match.group(0) == 'now':
            d = int(time.time())
        else:
            d = shift_time(match.group(1), match.group(2), match.group(3))

        print "Date: %s" % d
    else:
        usage()
        sys.exit(1)

if __name__ == '__main__':
    main()