usage: sock [ options ] <host> <port> (for client; default)
sock [ options ] -s [ <IPaddr> ] <port> (for server)
sock [ options ] –i <host> <port> (for "source" client)
sock [ options ] -i -s [ <IPaddr> ] <port> (for "sink" server)

options:

-b n bind n as client's local port number
-c convert newline to CR/LF & vice versa
-f a.b.c.d.p foreign IP address = a.b.c.d, foreign port# = p
-h issue TCP half close on standard input EOF
-i "source" data to socket, "sink" data from socket (w/-s)
-n n #buffers to write for "source" client (default 1024)
-p n #seconds to pause before each read or write (source/sink)
-q n size of listen queue for TCP server (default 5)
-r n #bytes per read() for "sink" server (default 1024)
-s operate as server instead of client
-u use UDP instead of TCP
-v verbose
-w n #bytes per write() for "source" client (default 1024)
-A SO_REUSEADDR option
-B SO_BROADCAST option
-C set terminal to cbreak mode
-D SO_DEBUG option
-E IP_RECVDSTADDR option
-F fork after connection accepted (TCP concurrent server)
-K SO_KEEPALIVE option
-L n SO_LINGER option, n = linger time
-N TCP_NODELAY option
-O n #seconds to pause after listen, but before first accept
-P n #seconds to pause before first read or write (source/sink)
-Q n #seconds to pause after receiving FIN, but before close
-R n SO_RCVBUF option
-S n SO_SNDBUF option
-U n enter urgent mode after write number n (source only)