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From: Chuck Swiger <cswiger@mac.com>
To: Mikhail Teterin <mi+kde@aldan.algebra.com>
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Date: Thu, 20 Dec 2007 10:48:40 -0800
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	<86r6hixiyn.fsf@bsd.by> <200712200458.27988@aldan>
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Cc: questions@freebsd.org, "Max N. Boyarov" <m.boyarov@bsd.by>
Subject: Re: tail does not exit
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On Dec 20, 2007, at 1:58 AM, Mikhail Teterin wrote:
> On =D1=81=D0=B5=D1=80=D0=B5=D0=B4=D0=B0 19 =D0=B3=D1=80=D1=83=D0=B4=D0=B5=
=D0=BD=D1=8C 2007, Chuck Swiger wrote:
> =3D A quick test suggests that "tail -f" will close when it gets a =20
> SIGPIPE.
>
> SIGPIPE? How is that relevant? Does tail get a SIGPIPE, when awk =20
> disappears
> in my example? If it does not, why do you bring it up?

tail should get a SIGPIPE when it tries to write to a pipeline where =20
the other end has closed.

> And if it does get SIGPIPE, then you are wrong, because the posted
> "quick test" shows the exact opposite behavior -- tail does NOT go
> away.
>
> Please, clarify... Thanks.

Worked for me.  I opened two SSH sessions to a FreeBSD 5.5 system, and =20=

did this in one:

% touch /tmp/logfile
% echo "line 1" >> /tmp/logfile

...and this in the other:

% tail -f /tmp/logfile | awk '{print "Line: " $1 ;  exit(0)}END{print =20=

"Bye"}'

...when I then did a:

% echo "line 2" >> /tmp/logfile

...in the first, the tail -f process terminated in the second.

--=20
-Chuck