pwd.py

import random
import math
import string
import sys
import click

# correct horse battery staple

def load_dictionary(d="/usr/share/dict/words"):
  f = open(d, "r")
  words = f.readlines()
  return list(
    filter(
      lambda w: w.isalpha(),
      map(lambda w: w.strip().lower(), words)
    )
  )

def pick_words(words, n):
  return random.choices(words, k=n)

def generate_password(words, sep="-", n=6, num=False):
  words = pick_words(words, n)
  if num:
    for i in range(n):
      digit = random.choice(string.digits)
      words.insert(n-i-1, digit)
  return sep.join(words)

@click.command()
@click.option("-c", "--count", default=4, help="Number of passwords to generate")
@click.option("-w", "--words", default=4, help="Number of words in a password")
@click.option("-s", "--sep", default="-", help="Seperator between words")
@click.option("--num/--no-num", default=False, help="Enable/disable adding numbers between words")
@click.option("--info/--no-info", default=True, help="Show/hide strength information")
@click.option("-d", "--dictionary", default="/usr/share/dict/words", help="Use a custom dictionary")

def program(count, words, sep, num, info, dictionary):
  """Generate a password from the system dictionary. xkcd.com/936"""

  d = load_dictionary(dictionary)
  
  if info:
    combinations = len(d) ** words
    if num:
      combinations *= len(string.digits) ** words
    print("With these options, there are {} possible passwords".format(combinations), file=sys.stderr)
    conventional_set = len(string.ascii_letters) + len(string.digits) + len(string.punctuation)
    conventional = math.ceil(math.log(combinations, conventional_set))
    print("The strength is equivalent to a {} character \"strong\" password".format(conventional), file=sys.stderr)
    print(file=sys.stderr)

  for i in range(count):
    p = generate_password(d, sep=sep, n=words, num=num)
    print(p)

if __name__ == "__main__":
  program()