Re: tail and grep

[Patrick Olson <patricko@open.org>]

> > tail -f /var/log/messages | grep "local  IP" > /home/pppusers/dynamic.IP
> > 
> > it does nothing but create a 0 byte file.
> 
> "tail -f" will run forever; output to the file won't be flushed until you've
> written a certain amount to the file -- one line obviously isn't enough.
> The screen on the other hand is flushed immediately. I suspect you don't
> really need the -f for tail, especially if you are just running this
> from the ip-up script or something.

If I ran tail from the script without the -f, it would terminate
immediately.  Since tail would terminate before the chat part of the
script has even finished, it would never see the string I'm looking for.

Am I making any sense here?




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