Generate password with configurable included character classes.

pwgen.py

#!/usr/bin/env python3

import argparse
import secrets
import string

def GetParser():
  parser = argparse.ArgumentParser(description="A very opinionated password generator.")
  parser.add_argument(
    '-a', '--lower', action='store_const', const=True, help='include lower case alphabets, default is true.')
  parser.add_argument(
    '-A', '--upper', action='store_const', const=True, help='include upper case alphabets. default is true.')
  parser.add_argument(
    '-1', '--number', action='store_const', const=True, help='include numbers. default is true.')
  parser.add_argument(
    '-@', '--special', action='store_const', const=True, help='include special characters. default is false.')
  parser.add_argument(
    'length', action='store', default=6, nargs='?', help='the length of the password, default 6')
  parser.add_argument(
    'count', action='store', default=5, nargs='?', help='the number of passwords to be generated, default 5')
  return parser

def generate_charset(lower, upper, number, special):
  ret = []
  if lower:
    ret += list(string.ascii_lowercase)
  if upper:
    ret += list(string.ascii_uppercase)
  if number:
    ret += list(string.digits)
  if special:
    ret += list("!@#$%^&*_+=-")
  return ret

def main():
  args = GetParser().parse_args()

  chars = []

  if not args.lower and not args.upper and not args.number:
    chars = generate_charset(True, True, True, args.special)
  else:
    chars = generate_charset(
      args.lower, args.upper, args.number, args.special)

  for i in range(args.count):
    pw = ''.join(secrets.choice(chars) for i in range(args.length))
    print(pw)

if __name__ == '__main__':
  main()