"netcat++" (extended design, new implementation)

socat is a relay for bidirectional data transfer between two independent
data channels. Each of these data channels may be a file, pipe, device
(serial line etc. or a pseudo terminal), a socket (UNIX, IP4, IP6 - raw,
UDP, TCP), an SSL socket, proxy CONNECT connection, a file descriptor
(stdin etc.), the GNU line editor (readline), a program, or a
combination of two of these.  These modes include generation of
"listening" sockets, mamed pipes, and pseudo terminals.