Simple command-line pseudo terminal manager:
allows to run coprocesses talking to each other thru their tty and/or pty.

Most useful to drive from scripts programs that want a tty, as in
	cotty -d -- pppd silent 192.168.0.1:192.168.0.2 \
		-- ssh -t root@remote pppd
This particular use has been obsoleted under Linux
(but probably not under the various free BSDs and proprietary Unices),
as it can be done without cotty with
	pppd pty 'ssh -t root@remote pppd' silent 192.168.0.1:192.168.0.2