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Date: Fri, 12 Dec 2008 18:14:06 +0200
From: Danny Braniss <danny@cs.huji.ac.il>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: preventing FIFO from EOF 
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> Danny Braniss wrote:
> >> $ mkfifo /var/tmp/foo
> >> $ buffer -i /var/tmp/foo                    # misc/buffer
> >> # in another console:
> >> $ echo hi > /var/tmp/foo
> >>
> >> buffer prints hi and exits. I want it to keep reading and printing 
> >> indefinitely.
> >>
> >> Further experimentation revealed that I need two writers: one dummy 
> >> writer that just keeps /var/tmp/foo open for writing, and the other 
> >> doing the "real work". This way buffer wouldn't exit. But how to emulate 
> >> the dummy writer? It itself needs to block on something to keep 
> >> /var/tmp/foo open. Any clean way to do this in shell? Maybe the solution 
> >> is quite simple but isn't at the tip of my tongue.
> >>
> >> Thanks.
> > 
> > too easy
> > n csh:
> > 	while 1
> > 		buffer -i /var/tmp/foo 
> > 	end
> > or in sh:
> > 	while true; do
> > 		buffer -i /var/tmp/foo
> > 	done
> > 
> 
> > Thanks, but I should have said that buffer must always run to never miss any data. 
> 
> The reason being that buffer's output gets fed into another program that 
> shouldn't be restarted.

use 'tail -f' instead of 'buffer -i' then, or place the while in file
and execute that. BTW, buffer was written way back when memory was measured
in kilobytes and the ethernet was 10 mgb, so things have changed a bit, and
its effectivness is questionable :-)

danny