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Date:      Fri, 16 Dec 2005 10:36:34 -0600
From:      Dan Nelson <dnelson@allantgroup.com>
To:        "Roman Gorohov.              " <roma.a.g@gmail.com>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: easy question about kill command
Message-ID:  <20051216163634.GD89708@dan.emsphone.com>
In-Reply-To: <979057908.20051216120816@gmail.com>
References:  <14510301213.20051216105225@gmail.com> <200512160846.jBG8kaEB099405@lurza.secnetix.de> <979057908.20051216120816@gmail.com>

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In the last episode (Dec 16), Roman Gorohov.               said:
> Oliver Fromme wrote:
> 
> > roma.a.g <roma.a.g@gmail.com> wrote:
>  >> Is there anyone who can explain me, why when i say 'kill -HUP id',
>  >> and its failed to restart, kill say nothing?
> 
> > There is no way for the kill command to know what the target
> > process is going to do with the signal.  This is entirely and only
> > the business of the target process, which might chose to take the
> > default action (in the case of SIGHUP it's to terminate the
> > process), to ignore the signal alltogether, or to take some special
> > action. Some programs use SIGHUP traditionally to rotate their
> > logfiles, re-read configuration files, re-open network sockets,
> > restart themselves, or other things.  But that's entirely up to the
> > program in question, and there is no way the kill command could
> > know about it, let alone whether it was successful or not.
> 
> Thanks for your reply. My question was about standard bsd daemons,
> not about some apps with unpredictable behaviour.

It still depends on what daemon you're talking about.  syslogd, for
example, re-reads /etc/syslog.conf and reloads its logfiles on SIGHUP. 
Luckily, most base daemons are started from their own /etc/rc.d/*
scripts which know how that particular program works, so you can use
them to start/stop/restart daemons and not have to look up pids
manually.

-- 
	Dan Nelson
	dnelson@allantgroup.com



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