Connect to a netgraph node.
nghook [-adlnSs] [-m msg] path [hookname] nghook -e [-n] [-m msg] path hookname program [args ...]
The nghook utility creates a ng_socket socket type node and connects it to hook hookname of the node found at path. If hookname is omitted, '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 arguments 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:
Option | Description |
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-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. (Not supported by INtime) |
-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 signal. |
-S |
Use file descriptor 0 for output instead of the default 1. |
-s |
Use file descriptor 1 for input instead of the default 0. |
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.
Versions |
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INtime 4.0 |
ngctl, ng_socket, netgraph