Path: utzoo!attcan!uunet!mcvax!hp4nl!orcenl!bengsig
From: bengsig@orcenl.uucp (Bjorn Engsig)
Newsgroups: comp.unix.wizards
Subject: Re: Bug/misfeature in 4bsd /bin/sh
Summary: Logical OR ?
Message-ID: <193.nlunix6@orcenl.uucp>
Date: 21 Nov 88 09:02:58 GMT
References: <117@sickkids.UUCP> <5538@sdcrdcf.sm.unisys.com>
Organization: ORACLE Europe, The Netherlands
Lines: 20

In article <5538@sdcrdcf.sm.unisys.com>, eggert@sea.sm.unisys.com (Paul Eggert) writes:
> Mark Bartelt complained that in Berkeley Unix the shell command (X|Y|Z)
  ...
> 
> Unfortunately, under either semantics, you can't tell whether all the commands
> in a pipeline succeed.  Instead, (X|Y|Z) should yield the logical OR of the
> exit statuses of X, Y, and Z.  Why didn't AT&T see this?
Oh no!  We have the logical OR and AND as || and &&, and they are of course
not pipe-symbols (they combine pipelines).

Do you mean that (x|y|z) should never call z if y returned non-zero?
Or should the all be called and the return codes simply logical OR'ed?
In this case, what would the meaning be of, say 1|2|3 == 3, or 1|0|3 == 3?

The SysV behaviour is the only acceptable one.

-- 
Bjorn Engsig, ORACLE Europe      \ /    "Hofstaedter's Law:  It always takes
 ..!uunet!mcvax!orcenl!bengsig    X      longer than you expect, even if you
phone:  +31 21 59 56 411         / \     take into account Hofstaedter's Law"