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Date:      Thu, 18 Sep 1997 13:21:46 +0930
From:      Greg Lehey <grog@lemis.com>
To:        "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com>
Cc:        question@lemis.com
Subject:   Re: sorry to ask a freebsd-question question!
Message-ID:  <19970918132146.48861@lemis.com>
Resent-Message-ID: <199709180354.NAA15585@freebie.lemis.com>
In-Reply-To: <199709171427.HAA08519@GndRsh.aac.dev.com>; from Rodney W. Grimes on Wed, Sep 17, 1997 at 07:27:09AM -0700
References:  <Pine.BSF.3.91.970917200519.818Q@panda.hilink.com.au> <199709171427.HAA08519@GndRsh.aac.dev.com>

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On Wed, Sep 17, 1997 at 07:27:09AM -0700, Rodney W. Grimes wrote:
>> On Wed, 17 Sep 1997, xiyuan qian wrote:
>>
>>>  Hi, I know "ps -ax | grep ppp" can find the ppp running's pid, but when I do
>>>  that, it sometimes show me
>>>      616 ....  ppp
>>>      716 ....  ps -ax | grep ppp
>>>  or sometimes it only show me
>>>      616 ....ppp
>>>  Why? How can I deny the "ps -ax | grep ppp"  showing out?
>>
>> ps -ax | fgrep ppp | fgrep -v fgrep
>
> Stop with the silliness, just go get pppd's pid(s) from /var/run/ppp*.pid

You're assuming that's all he wants to know.  There are really two
questions here.  One has been answered to death.  The other one is
"why do I sometimes get the grep process listed and sometimes not?".
The answer is that it's a race condition in the process table.  I
still can't understand why it happens so often, though.

Greg



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