-                         Use IPv4 only

             -                         Use IPv6 only

             -U, --unixsock             Use Unix domain sockets only

             -C, --crlf                 Use CRLF for EOL sequence

             -c, --sh-exec <command>    Executes the given command via /bin/sh

             -e, --exec <command>       Executes the given command

                 --lua-exec <filename>  Executes the given Lua script

             -g hop1[,hop2,...]         Loose source routing hop points ( max)

             -G <n>                     Loose source routing hop pointer (, , , ...)

             -m, --max-conns <n>        Maximum <n> simultaneous connections

             -h, --help                 Display this help screen

             -d, --delay <time>         Wait between read/writes

             -o, --output <filename>    Dump session data to a file

             -x, --hex-dump <filename>  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

             -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

                 --sctp                 Use SCTP instead of default TCP

             -v, --verbose              Set verbosity level (can be used several times)

             -w, --wait <time>          Connect timeout

                 --append-output        Append rather than clobber specified output files

                 --send-only            Only send data, ignoring received; quit on EOF

                 --recv-only            Only receive data, never send anything

                 --allow                Allow only given hosts to connect to Ncat

                 --allowfile            A file of hosts allowed to connect to Ncat

                 --deny                 Deny given hosts 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

nc -l