rp: generate a random password from a seed.

Usage: rp <options>

Options:
	-s <skipchars>		Characters to not use.
	-c <charlist>		Use charlist characters only.
	-a			"ascii", use [a-z0-9] only
	-A			"ascii", use [A-z0-9] only
	-l <n>			Length of passwd (default: 8)
	-u			Unique, do not repeat chars.
	-q,-n			Quiet (no echo) when prompting for seed.
	-D			Decimal digits only.
	-hex			Hexidecimal digits only.
	-mac			-hex and separate pairs of hex digits with ":"
	-N <n>			Use the first <n> chars of the list.
				A-Za-z0-9~!@#0^&*(){}[]_+-=|:;,./<>?
	-x			use /dev/urandom for seeding.
	-d			Debug mode.

Notes:
	To get a random permutation of the alphabet do:
	rp -u -l 26 -N 26 <seed>