freebsd man page for nghook

NGHOOK(8)						    BSD System Manager's Manual 						 NGHOOK(8)

NAME
     nghook -- connect to a netgraph(4) node

SYNOPSIS
     nghook [-adlnSs] [-m msg] path [hookname]
     nghook -e [-n] [-m msg] path hookname program [args ...]

DESCRIPTION
     The nghook utility creates a ng_socket(4) socket type node and connects it to hook hookname of the node found at path.  If hookname is omit-
     ted, ``debug'' is assumed.

     If the -e option is given, the third argument is interpreted as the path to a program, and this program is executed with the remaining argu-
     ments as its arguments.  Before executing, the program Netgraph messages (specified by the -m option) are sent to the node.  The program is
     executed with its standard input (unless closed by -n) and output connected to the hook.

     If the -e option is not given, all data written to standard input is sent to the node, and all data received from the node is relayed to
     standard output.  Messages specified with -m are sent to the node before the loop is entered.  The nghook utility exits when EOF is detected
     on standard input in this case.

     The options are as follows:

     -a      Output each packet read in human-readable decoded ASCII form instead of raw binary.

     -d      Increase the debugging verbosity level.

     -e      Execute the program specified by the third argument.

     -l      Loops all received data back to the hook in addition to writing it to standard output.

     -m msg  Before executing the program (in -e mode) send the given ASCII control message to the node.  This option may be given more than once.

     -n      Do not attempt to read any data from standard input.  The nghook utility will continue reading from the node until stopped by a sig-
	     nal.

     -S      Use file descriptor 0 for output instead of the default 1.

     -s      Use file descriptor 1 for input instead of the default 0.

SEE ALSO
     netgraph(3), netgraph(4), ngctl(8)

HISTORY
     The netgraph system was designed and first implemented at Whistle Communications, Inc. in a version of FreeBSD 2.2 customized for the Whistle
     InterJet.

AUTHORS
     Archie Cobbs <archie@whistle.com>

BUGS
     Although all input is read in unbuffered mode, there is no way to control the packetization of the input.

     If the node sends a response to a message (specified by -m), this response is lost.

BSD
								 October 24, 2003							       BSD