random

#!/usr/bin/env python

import os, sys, string


def get_terminal_size():
	def ioctl_GWINSZ(fd):
		try:
			import fcntl, termios, struct
			cr = struct.unpack('hh', fcntl.ioctl(fd, termios.TIOCGWINSZ, '1234'))
		except: return
		return cr
	cr = ioctl_GWINSZ(0) or ioctl_GWINSZ(1) or ioctl_GWINSZ(2)
	if not cr:
		try:
			fd = os.open(os.ctermid(), os.O_RDONLY)
			cr = ioctl_GWINSZ(fd)
			os.close(fd)
		except: pass
	if not cr: cr = 0, 0
	return int(cr[1]), int(cr[0])


def main(args=None):
	import argparse
	parser = argparse.ArgumentParser(description='Generate a pseudorandom strings.')
	parser.add_argument('-n', '--length',
		type=int, default=39, metavar='n',
		help='Length of a produced string. Default: %(default)s')
	parser.add_argument('-r', '--rows',
		type=int, default=10, metavar='n',
		help='Rows of passwords to produce. Default: %(default)s')
	parser.add_argument('-s', '--simple',
		action='store_true', help='Use only letters/numbers.')
	parser.add_argument('-d', '--digits',
		action='store_true', help='Use only numbers (digits).')
	parser.add_argument('-x', '--hex-digits',
		action='store_true', help='Use numbers + a-f lowecase hex digits.')
	parser.add_argument('-1', '--one',
		action='store_true', help='Output just one generated password.')
	opts = parser.parse_args(sys.argv[1:] if args is None else args)

	if sum(map(bool, [opts.digits, opts.simple])) > 1:
		parser.error('Multiple output modes specified at the same time')

	if opts.digits: chr_range = string.digits.encode()
	elif opts.hex_digits: chr_range = (string.digits + 'abcdef').encode()
	elif opts.simple: chr_range = (string.ascii_letters + string.digits).encode()
	else:
		chr_range = (string.ascii_letters + string.digits).encode()
		chr_range += ( string.punctuation.replace("'", '').replace('"', '')
			.replace('`', '').replace('\\', '').replace('!', '').replace('$', '') ).encode()

	def src():
		with open('/dev/urandom', 'rb') as src:
			while True: yield src.read(1)
	src = (c for c in src() if c in chr_range)
	getpass = lambda n: bytearray(ord(next(src)) for m in range(n)).decode()

	if opts.one:
		return print(getpass(opts.length))

	(w, h), pad = get_terminal_size(), 3
	for n in range(opts.rows):
		row_left = w
		while True:
			print(getpass(opts.length), end='')
			row_left -= opts.length
			if not row_left or row_left < (pad + opts.length): break
			print(' '*pad, end='')
			row_left -= pad
		print()

if __name__ == '__main__': sys.exit(main())