NAME
snooper - a utility for capturing data flowing between serial devices
SYNOPSIS
snooper [-h]
snooper [-b baudrate] [-t] [-u] [-x] [-n] port0 port1
DESCRIPTION
snooper passes data transparently between two serial (RS232C) devices,
capturing and logging the data and occasional comments you want to insert
into the logs.
It is useful for debugging or analyzing the communications protocol
between two devices that would normally be connected directly to each
other, e.g. a digital camera and a personal computer. By sitting in the
middle (after you connect the two devices to serial ports on your Linux
machine) snooper is able to capture data traveling in either direction
while also passing it unmodified to the other device.
It is also possible to operate with a single serial device, using your
console and keyboard as the second device.
OPTIONS
-b baudrate
Specify baudrate to use. Default baudrate is 9600.
-t Include current time (in microseconds) with each write to the
textual log file. See L under KEYBOARD COMMANDS, below.
-u Do not perform serial device locking. (This option is
discouraged, and should never be necessary on a properly-
configured Debian system.)
-x Hex display only. (Even printable characters will be displayed
in hex.)
-n Do not forward traffic between the two ports; useful when you
have a splitter cable.
-h Help; presents a brief synopsis of the command line options.
KEYBOARD COMMANDS
snooper has a set of commands that act similar to those of vi.
Note that the characters transmitted into the serial ports will not be
forwarded while snooper is in command parameter input mode. You should
therefore set the log file and so forth while the serial line has no
activity.
L Switch textual log file. You’ll be asked to answer the filename
of the log file.
B Switch binary log file. You’ll asked to answer which device to
log, and the log file name. Please note that the binary log will
contain the input from the perspective of snooper. Therefore, if
you would like to make a log of input of line 0 (thus the output
from device connected to line 0), you shold specify line 0. You
should use a file that is local, or on a virtual disk, so that no
characters will be lost.
m add a memo line to the text log file. The memo line will contain
a timestamp and the text you provide.
Q Quit.
c Reset the counter.
b Change the baudrate.
C Make the console act as one of the serial lines. ESC Go back to
command mode. ^V Quote the next char (so that you can send ESC,
for example). ^X input a byte by its 2-character hexadecimal
value (so that you can send any character you like). By tapping
any other key, that character will be sent to the line.
^L Repaint the screen.
An unrecognized command character will present a brief list of the valid
command characters.
EXAMPLE
snooper /dev/ttyS0 /dev/ttyS1
AUTHOR
Jun-ichiro Itoh <itojun@itojun.org>
This man page was written by David Coe <davidc@debian.org> for the Debian
project, and may be used by others under the terms of the GNU General
Purpose License, version 2 or later.