Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > gnu.bash.bug > #11572

Re: command substitution is stripping set -e from options

Path csiph.com!xmission!news.glorb.com!usenet.stanford.edu!not-for-mail
From Christoph Gysin <christoph.gysin@gmail.com>
Newsgroups gnu.bash.bug
Subject Re: command substitution is stripping set -e from options
Date Fri, 2 Oct 2015 14:09:21 +0300
Lines 41
Approved bug-bash@gnu.org
Message-ID <mailman.269.1443788211.16064.bug-bash@gnu.org> (permalink)
References <CADex794C1jOf0wrB298_O4ohAqZghYUdd9DJcuaOvV1dCP5AOQ@mail.gmail.com> <560D83DA.9020405@redhat.com>
NNTP-Posting-Host lists.gnu.org
Mime-Version 1.0
Content-Type text/plain; charset=UTF-8
X-Trace usenet.stanford.edu 1443788211 12140 208.118.235.17 (2 Oct 2015 12:16:51 GMT)
X-Complaints-To action@cs.stanford.edu
Cc bug-bash@gnu.org
To Eric Blake <eblake@redhat.com>
Envelope-to bug-bash@gnu.org
DKIM-Signature v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=P/B2ntnSVRY1ZTuirnybEVkeM8T2Vo6r2PwtPDAanTQ=; b=m/yUTqz8oSjHkVk3Z5ZPNkyTrw6l4QIhi1I9RTxETq7/Mc9/PAV6V8S6z2fQUgLf5a YWlNvjRww4QJHM57HJBuTvuMH23SbVpRMIBPeMBgWtC69bhQVuqr7YZ12A2D079p1WDa TRtz16Lr1DKyZoVTysIfRG7QPwnnT3DsFYGVp1OpRNTTXwpeeL9244Bz4RTr0mUO5vp0 yrWT+QuVgGeORgXLMorh9zuecVHbyP+Ln+pRByTrRyO5ZMvpD5uSCtOakAneS8uXWl/Q n+iG/05mfn6ZnlSm1V+BSH7ZrxvecAyY/CP8nru6BZIQVsqKAT2l/f1SwCs0zyTYzNjf R+9A==
X-Received by 10.112.139.201 with SMTP id ra9mr5246361lbb.29.1443784200440; Fri, 02 Oct 2015 04:10:00 -0700 (PDT)
In-Reply-To <560D83DA.9020405@redhat.com>
X-detected-operating-system by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value).
X-Received-From 2a00:1450:4010:c03::22f
X-BeenThere bug-bash@gnu.org
X-Mailman-Version 2.1.14
Precedence list
List-Id Bug reports for the GNU Bourne Again SHell <bug-bash.gnu.org>
List-Unsubscribe <https://lists.gnu.org/mailman/options/bug-bash>, <mailto:bug-bash-request@gnu.org?subject=unsubscribe>
List-Archive <http://lists.gnu.org/archive/html/bug-bash>
List-Post <mailto:bug-bash@gnu.org>
List-Help <mailto:bug-bash-request@gnu.org?subject=help>
List-Subscribe <https://lists.gnu.org/mailman/listinfo/bug-bash>, <mailto:bug-bash-request@gnu.org?subject=subscribe>
Xref csiph.com gnu.bash.bug:11572

Show key headers only | View raw


> Whether e disappears from $- may be unintended, but what IS documented
> is that there are contexts in which set -e has no effect, and when in
> one of those contexts, you cannot re-enable set -e.  One such context is
> on the left side of && or ||.  Even more non-intuitively, if you have a
> function that tries to use set -e, the effect of set -e depends on the
> context of where the function is called (that is, 'f' may behave
> differently than 'f || true').

Yes, I'm aware of all those, and I think they make sense. They are
also documented.

> What's wrong with:
>   var=$(command1 && command2) || exit

Because the code is:

f() {
  some command
  more commands --with-args
}

output=$(f)

Since set -e does not work, it means I have to postfix every command
with "|| exit $?":

f() {
  some command || exit $?
  more commands --with-args || exit $?
}

output=$(f)

My understanding was the the whole point of set -e was to have that
behaviour by default for every command (with the documented
exceptions).

Chris
-- 
echo mailto: NOSPAM !#$.'<*>'|sed 's. ..'|tr "<*> !#:2" org@fr33z3

Back to gnu.bash.bug | Previous | Next | Find similar


Thread

Re: command substitution is stripping set -e from options Christoph Gysin <christoph.gysin@gmail.com> - 2015-10-02 14:09 +0300

csiph-web