Command to parse a human date description and output a date.

human-date-parser.py

#!/usr/bin/python

from __future__ import print_function # Need to grab the print function from Python 3.

import parsedatetime # Requires "parsedatetime" Python module

from datetime import datetime
import argparse

argparser = argparse.ArgumentParser()

argparser.add_argument("input", nargs='?', help="text to convert into a date.")
argparser.add_argument("-d", "--dash", action="store_true", help="use dashes instead of slashes as a seperator.")
argparser.add_argument("-g", "--github", action="store_true", help="output in GitHub dashed format, i.e. \"yyyy-mm-dd\"")

args = argparser.parse_args()

if args.dash or args.github:
	dateSeparator = "-"
else:
	dateSeparator = "/"

if not args.input: # If there's nothing on the command line, read from the clipboard.
	try:
		from Tkinter import Tk # Might need to get tkinter from your package manager on Linux.
	except:
		from tkinter import Tk # Fix for Python 3, which changed the case of Tkinter.
	r = Tk()
	r.withdraw()

	result = r.selection_get(selection = "CLIPBOARD")
else:
	result = args.input

cal = parsedatetime.Calendar()

time_struct, parse_status = cal.parse(result)
parsedDate = datetime(*time_struct[:6])
if not args.github:
	printDate = str(parsedDate.month) + dateSeparator + str(parsedDate.day) + dateSeparator + str(parsedDate.year) # Using the admittedly horrible American date format.
else:
	printDate = str(parsedDate.year) + dateSeparator + str(parsedDate.month).zfill(2) + dateSeparator + str(parsedDate.day).zfill(2)

print(printDate, end="")

# r.clipboard_clear()
# r.clipboard_append(printDate) # Code to send to clipboard, broken in Python 3, worked around by printing output and piping to clip.exe/xsel -ib
if not args.input:
	r.destroy()

I used this recently to get GitHub commits within a time period.

Example:

git log --all --after="`human-date-parser.py -g 'two weeks ago'` 00:00" --before="`human-date-parser.py -g 'today'` 23:59"