Path: utzoo!attcan!uunet!cs.utexas.edu!usc!bloom-beacon!mgm.mit.edu!wolfgang
From: wolfgang@mgm.mit.edu (Wolfgang Rupprecht)
Newsgroups: comp.unix.wizards
Subject: pipe breaking mystery
Message-ID: <13539@bloom-beacon.MIT.EDU>
Date: 16 Aug 89 04:31:58 GMT
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: wolfgang@mgm.mit.edu (Wolfgang Rupprecht)
Organization: Freelance Software Consultant, Washington DC.
Lines: 22

Here is a new puzzler.  Observed on a sun3 w. sunos 3.4.  I have a
piped command line passed to /bin/sh in a script for frobbing the RCS
command "ci".  (The script, in theory, checks in all RCS-ed files in a
subtree.)  The pipe sometimes breaks with a partial line making it to
the last section of the pipe and execution stopping prematurely.  When
run one piece at a time it always works.  The script breaking is
probabalistic.  One observed "fact" is that the breakage is usually
within a half screen of ci barfing about something.

Any hints how even to get a handle on this?  I'm curious how other
folks deal with bugs of this type.

This is the script:

	#!/bin/sh
	DIR=`cd ${1-.}; pwd`   # conv to abs path
	find $DIR -name "RCS" -print | sed -e 's:/RCS$::' \
		-e 's:.*:cd & ; ci RCS/*:' | /bin/sh -sx

-wolfgang
Wolfgang Rupprecht	ARPA:  wolfgang@mgm.mit.edu (IP 18.82.0.114)
TEL: (703) 768-2640	UUCP:  mit-eddie!mgm.mit.edu!wolfgang