Date: Sun, 4 Nov 2007 01:28:36 +0100 From: Erik Trulsson <ertr1013@student.uu.se> To: deeptech71@gmail.com Cc: freebsd-questions@freebsd.org Subject: Re: reverse grep Message-ID: <20071104002836.GA1526@owl.midgard.homeip.net> In-Reply-To: <472D0E7D.6050209@gmail.com> References: <472D0E7D.6050209@gmail.com>
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On Sun, Nov 04, 2007 at 01:12:45AM +0100, deeptech71@gmail.com wrote: > How is it possible to select lines that do NOT match a specific pattern? By using the '-v' option to grep. > > For example, I'm connecting to 192.168.123.254 via telnet (port 23), and do > tcpdump -nli rl0. This cyclic traffic, becuase when tcpdump outputs > something, the system sends me some packets, which generates output in > tcpdump, and vice versa. I want to filter out packets of telnet access to > the FreeBSD machine, that is, something like: > > tcpdump -nli rl0 | grep --non-matching-lines 192.168.123.254.23 You can also tell tcpdump directly to not generate certain output. E.g. 'tcpdump -nli rl0 not port 23' will not display any traffic to/from port 23. Read the tcpdump(1) manpage for the details - many more options are available. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se
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