reverse grep

[Gary Kline]

On Sun, Nov 04, 2007 at 01:12:45AM +0100, deeptech71 at gmail.com wrote:
> How is it possible to select lines that do NOT match a specific pattern?
> 
> 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

      % tcpdump -nli rl0 | grep -v 192.168.123.254.23

      will print everything except the IP you have shown.   
-- 
  Gary Kline  kline at thought.org   www.thought.org  Public Service Unix
      http://jottings.thought.org   http://transfinite.thought.org