Path: csiph.com!optima2.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!usenet.stanford.edu!not-for-mail From: Chet Ramey Newsgroups: gnu.bash.bug Subject: Re: command substitution is stripping set -e from options Date: Sat, 10 Oct 2015 13:24:36 -0400 Organization: ITS, Case Western Reserve University Lines: 34 Approved: bug-bash@gnu.org Message-ID: References: <560D83DA.9020405@redhat.com> <20151002122925.GK25574@eeg.ccf.org> <20151002132221.GL25574@eeg.ccf.org> <56103208.30406@case.edu> <56168B10.1000905@case.edu> Reply-To: chet.ramey@case.edu NNTP-Posting-Host: lists.gnu.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Trace: usenet.stanford.edu 1444497929 22256 208.118.235.17 (10 Oct 2015 17:25:29 GMT) X-Complaints-To: action@cs.stanford.edu Cc: Greg Wooledge , bug-bash@gnu.org, chet.ramey@case.edu To: Christoph Gysin Envelope-to: bug-bash@gnu.org User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 In-Reply-To: X-Junkmail-Whitelist: YES (by domain whitelist at mpv1.tis.cwru.edu) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 129.22.105.36 X-BeenThere: bug-bash@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Bug reports for the GNU Bourne Again SHell List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com gnu.bash.bug:11603 On 10/8/15 2:36 PM, Christoph Gysin wrote: >> I think you're overlooking what I referred to above: that the exit status >> of a command substitution doesn't have any effect on whether the parent's >> command succeeds or fails except in one case: the right-hand-side of an >> assignment statement that is the last assignment in a command consisting >> only of assignment statements. To say that it `disables the whole point >> of set -e' is a considerable overstatement. > > Well, I do see your point. But my understanding was that if I wanted > to run all my bash code with set -e error checking, I can do so by > avoiding a couple of corner cases, namely: There are many more cases where the setting of -e has no effect. We discussed this extensively on the posix mailing list a few years ago, and the result of that discussion is at http://austingroupbugs.net/view.php?id=52 For example, even if you attempt to enable -e in a shell function, it will have no effect if you run it as the command after `if'. It seems like you're restricting the discussion to simple commands only, and only to those commands that contain command subsitutions. I think this is what Greg is talking about. I will consider adding an option to change the behavior of command substitution inheriting the -e option, since there doesn't seem to be any way to decouple this behavior from posix mode. -- ``The lyf so short, the craft so long to lerne.'' - Chaucer ``Ars longa, vita brevis'' - Hippocrates Chet Ramey, ITS, CWRU chet@case.edu http://cnswww.cns.cwru.edu/~chet/