On Wed, Jun 26, 2002 at 05:58:01PM +0000, Jennifer Tso wrote (in HTML;
please don't send HTML-only mail to the Ethereal mailing lists, as not
everybody on the list uses mail readers that handle HTML mail
conveniently):
> I am trying to get the ouput that tethereal gives to go to a file. The
> command I use to generate output is:
>
> tethereal -i \Device\Packet{...}
>
> This outputs the information to the screen. I need it to go to a file.
> So I tried:
>
> tethereal -i \Device\Packet{...} -w test.txt
>
> This generates an empty file named test.txt.
Tethereal, by default, loops forever; to stop a capture, you have to
type control-C. The output file will not necessarily contain anything
until you interrupt Tethereal with a control-C.
In addition, there is a bug in Tethereal that causes it to terminate
abnormally when you interrupt it with a control-C, so you might not even
get anything in the output file if you *do* type control-C. I've just
checked in a fix for that, which will be in the next Ethereal release.
However, if you do
tethereal -i \Device\Packet{...} -w test.txt
it will *NOT* write to the file the same text that it would print to the
screen if you run it with
tethereal -i \Device\Packet{...}
In fact, it will not write text at all - instead, it will write a
*binary* file containing time stamps for the packets, packet sizes, and
raw data for the packets. That file can be read by Tethereal with the
"-r" flag, with Ethereal, with WinDump, and with other programs that can
read tcpdump/WinDump output.
If you want to get *text output* to a file, you should do
tethereal -i \Device\Packet{...} > test.txt
However:
> I thought the output is
> suppose to go to this file. Am I doing something wrong? I tried to get
> around the whole thing by trying:
>
> tethereal -i \Device\Packet{...} > test.txt
>
> But it seems that tethereal does not send output to stdout. So that
> didn't work either. Does anyone have any suggestions?
It *does*, if run without the "-w" flag, send output to the standard
output. However, the same problems I mentioned earlier, namely that
1) it will loop forever, so you have to terminate it with
control-C
and
2) it'll terminate abnormally when you use control-C, so it may
not write anything
apply in that case as well; you'd have to wait for the next release for
the fix to that problem.
