X-Recipient: archive-cygwin AT delorie DOT com DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:mime-version:content-type :content-transfer-encoding:message-id:date:to:subject :in-reply-to:references; q=dns; s=default; b=N8Ua+KtEaCsJLt0CFQJ RYzdnSBVmXQqzHtkrTOhZoFFsX/YclGFR4cVH3wcG2/4gStvrI3Pg+O0x3fY8nt0 +77QyncAf5djeG3KCUX1XR96yb1aVc5zgr5eEmCRFkNe0OfnhLkAiaP93a57OPdj Nd7IBu528eZTwuNoqE+I6NdU= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:mime-version:content-type :content-transfer-encoding:message-id:date:to:subject :in-reply-to:references; s=default; bh=2yHzkUYGW0vlYv2f+kIo0ApNI 1o=; b=Xcyt+n3YOWnSiLE4fDrMG7Jf15ZeSSbHe3D7XGF1vw+GNs4+BxHWSKTxG ueQJ5yvywUD+z/Dnv7amLRmfc+TxAVD225EyGamlU5A5T9CHTzGdDFYOcgsWuyij 2Xd+7G6oH/nMxn1fE3+9DNIWS8nQpL0IAyqz9PkL6h/sUEQUBY= Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2 X-HELO: vms173003pub.verizon.net From: MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit Message-id: <21095.51020.811223.778148@consult.pretender> Date: Wed, 23 Oct 2013 08:55:40 -0400 To: cygwin AT cygwin DOT com Subject: Re: ps weirdness... In-reply-to: <20131023082535.GA5134@calimero.vinschen.de> References: <21093 DOT 42532 DOT 550364 DOT 992074 AT consult DOT pretender> <20131023082535 DOT GA5134 AT calimero DOT vinschen DOT de> X-IsSubscribed: yes Corinna Vinschen wrote at about 10:25:35 +0200 on Wednesday, October 23, 2013: > On Oct 21 18:09, cygwin wrote: > > When I type 'ps', I get as expected the following processes: > > > > PID PPID PGID WINPID TTY UID STIME COMMAND > > 18036 3188 18036 17792 pty0 1001 16:54:33 /usr/bin/ps > > 3188 1688 3188 3212 pty0 1001 06:59:16 /usr/bin/bash > > 1688 1 1688 1688 ? 1001 06:59:15 /usr/bin/mintty > > 2392 1 2392 2392 ? 1001 11:00:03 /usr/bin/ssh-agent > > > > When I type 'ps | grep bash', about 2/3 of the time, I get: > > 3188 1688 3188 3212 pty0 1001 06:59:16 /usr/bin/bash > > > > HOWEVER, about 1/3 of the time, I get: > > 16832 3188 17792 16832 pty0 1001 16:56:44 /usr/bin/bash > > 3188 1688 3188 3212 pty0 1001 06:59:16 /usr/bin/bash > > When you pipe ps to grep, the shell forks and execs two processes, ps > and grep. What you see is one of the forked bash processes. They are > shortlived, but depending on the order of execution they may still > linger in the process list when ps creates the process list. > > > And there is no bash process launched in the interim. Moreover, this > > second PID jumps around (both up and down) wildly rather than being > > constant or even relatively sequential. > > PIDs under Windows are not sequential. > > > In such cases, ps -W, similarly generates 2 bash processes: > > > > 3188 1688 3188 3212 pty0 1001 06:59:16 /usr/bin/bash > > 16460 0 0 16460 pty0 1001 17:44:29 C:\cygwin\bin\bash.exe > > > > Even more interesting, when I type 'ps | grep ssh-agent', about 2/3 of the time, I get: > > 2392 1 2392 2392 ? 1001 11:00:03 /usr/bin/ssh-agent > > > > HOWEVER, about 1/3 of the time, I get: > > 2392 1 2392 2392 ? 1001 11:00:03 /usr/bin/ssh-agent > > 19176 0 0 19176 pty0 1001 Dec 31 /usr/bin/ssh-agent > > Hmm, I can't reproduce this one. I tried a hundreds of times, but > there was not a single instance of bash shown as a Windows process. The Windows case seemed to be less reproducible... but it did happen. Given your explanation as a short-lived forked process, I imagine it would depend to a degree on the speed and architectures (e.g., #cores) of the CPU. HOWEVER, I still don't understand the 'dec 31' date for a short-lived process... -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple