Ncat 5.05BETA1 ( http://nmap.org/ncat )
Usage: ncat [options] [hostname] [port]

Options taking a time assume milliseconds, unless you append an 's'
(seconds), 'm' (minutes), or 'h' (hours) to the value (e.g. 30s)
  -4                         Use IPv4 only
  -6                         Use IPv6 only
  -C, --crlf                 Use CRLF for EOL sequence
  -c, --sh-exec <command>    Executes specified command via /bin/sh
  -e, --exec <command>       Executes specified command
  -g hop1[,hop2,...]         Loose source routing hop points (8 max)
  -G n                       Loose source routing hop pointer (4, 8, 12, ...)
  -m, --max-conns n          Maximum n simultaneous connections
  -h, --help                 Display this help screen
  -d, --delay <time>         Wait between read/writes
  -o, --output               Dump session data to a file
  -x, --hex-dump             Dump session data as hex to a file
  -i, --idle-timeout <time>  Idle read/write timeout
  -p, --source-port port     Specify source port to use (doesn't affect -l)
  -s, --source addr          Specify source address to use (doesn't affect -l)
  -l, --listen               Bind and listen for incoming connections
  -k, --keep-open            Accept multiple connections in listen mode
  -n, --nodns                Do not resolve hostnames via DNS
  -t, --telnet               Answer Telnet negotiations
  -u, --udp                  Use UDP instead of default TCP
  -v, --verbose              Set verbosity level (can be used up to 3 times)
  -w, --wait <time>          Connect timeout
      --send-only            Only send data, ignoring received; quit on EOF
      --recv-only            Only receive data, never send anything
      --allow                Allow specific hosts to connect to Ncat
      --allowfile            A file of hosts allowed to connect to Ncat
      --deny                 Hosts to be denied from connecting to Ncat
      --denyfile             A file of hosts denied from connecting to Ncat
      --broker               Enable Ncat's Connection Brokering mode
      --chat                 Start a simple Ncat chat server
      --proxy <addr[:port]>  Specify address of host to proxy through
      --proxy-type <type>    Specify proxy type ("http" or "socks4")
      --proxy-auth <auth>    Authenticate with HTTP or SOCKS proxy server
      --ssl                  Connect or listen with SSL
      --ssl-cert             Specify SSL certificate file (PEM) for listening
      --ssl-key              Specify SSL private key (PEM) for listening
      --ssl-verify           Verify trust and domain name of certificates
      --ssl-trustfile        PEM file containing trusted SSL certificates
      --version              Display Ncat's version information and exit

See the ncat(1) manpage for full options, descriptions and usage examples