Jason Gerfen wrote:
> Bowie Bailey wrote:
> > Jason Gerfen wrote:
> > > Bowie Bailey wrote:
> > > > Jason Gerfen wrote:
> > > > > I am looking to do something which I am not sure perl can do.
> > > > > I would like to be able to issue a system command ex. tail -f
> > > > > /file and loop over that command while sorting the output.
> > > > > Is this possible? And if so could I see an example?
> > > >
> > > > open(LOG, "tail -f /var/log/messages |");
> > > > while (<LOG>) {
> > > > if (/something important/) {
> > > > print "Found something...\n";
> > > > }
> > > > }
> > > > close LOG; # Never get here, but for completeness...
> > > >
> > > > I'm not sure what you mean by sorting the output. Since there
> > > > is continuous input, there will be continuous output. You
> > > > could sort and display aggregated output at intervals rather
> > > > than having a real-time output stream.
> >
> > I have a few programs that do this exact thing. They tail the log
> > file and page or email me when they find something. The only
> > problem I have had is that it seems like the pipe will eventually
> > break if you leave it running for long enough.
>
> Well I am 'attempting' to write a simple perl daemon that will listen
> or 'tail -f /var/log/messages' for any iptables log which matches a
> 'DROP'ed packet.
That's simple enough. Just follow my code above.
> Upon seeing a matching condition it will fork a new process and then
> begin sorting the data and send me alerts etc.
Fork a new process? Why?
It sounds like you just want to watch for DROPs and send alerts. Why
the complication?
> Does that help explain it a bit more? I can include code if
> needed.
Code might help. Some sample output would help more. What exactly
are you expecting this program to send you?
--
Bowie
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