Ethereal-users: Re: [Ethereal-users] tethereal Question

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From: Sake Blok <sake@xxxxxxxxxx>
Date: Fri, 17 Feb 2006 09:56:36 +0100
Hi Francis,

> Its possible to capture traffic in a 20Mo files and than if its bigger it create a new file?

Yes, you can use the -b filesize:x option. That way tethereal makes 
capturefiles of x kilobyes (actually x times 1000 bytes).

> After i want to run a contab to delete files older than 2 days in directory...

If you are worried about running out of space, you can also use the 
-b files:y option to make a ring-buffer of files. That way only y files 
will be kept and the earlier ones will be deleted. This means that if 
traffic increases unexpectedly, you still don't run out of disk-space.

> Some one can help me?

putting it all together, to capture files of 1000000 bytes and only 
keeping three at a time would result in:

tethereal -w test.cap -b filesize:1000 -b files:3  &

This would leave you with the following files after a while:

$ ls -l *cap
-rwx------+ 1 blok None 1024402 Feb 17 09:51 test_00008_20060217095109.cap
-rwx------+ 1 blok None 1025438 Feb 17 09:51 test_00009_20060217095113.cap
-rwx------+ 1 blok None  499712 Feb 17 09:51 test_00010_20060217095117.cap

Please also notice the serial number and time that ethereal has added in 
the filename before the extension :)

I hope this helps...


Sake