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


Groups > gnu.bash.bug > #11546

Re: local keyword hides return code of command substitution

Path csiph.com!optima2.xanadu-bbs.net!xanadu-bbs.net!enother.net!enother.net!peer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!nntp.club.cc.cmu.edu!micro-heart-of-gold.mit.edu!bloom-beacon.mit.edu!bloom-beacon.mit.edu!171.64.64.130.MISMATCH!usenet.stanford.edu!not-for-mail
From Stephane Chazelas <stephane.chazelas@gmail.com>
Newsgroups gnu.bash.bug
Subject Re: local keyword hides return code of command substitution
Date Tue, 22 Sep 2015 17:22:15 +0100
Lines 30
Approved bug-bash@gnu.org
Message-ID <mailman.1608.1442938946.19560.bug-bash@gnu.org> (permalink)
References <20150922141956.9E7ED81A59@idallen-oak.home.idallen.ca> <20150922154520.GM25574@eeg.ccf.org>
NNTP-Posting-Host lists.gnu.org
Mime-Version 1.0
Content-Type text/plain; charset=us-ascii
X-Trace usenet.stanford.edu 1442938947 9135 208.118.235.17 (22 Sep 2015 16:22:27 GMT)
X-Complaints-To action@cs.stanford.edu
Cc bash@packages.debian.org, bug-bash@gnu.org, idallen@home.idallen.ca
To Greg Wooledge <wooledg@eeg.ccf.org>
Envelope-to bug-bash@gnu.org
DKIM-Signature v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=dd2d4+FJuCJflNNGy909Rn9iwMXmIreQGop4PBKk22g=; b=xIOV11YqvJ0EF85tLKrE8mwgZNAmPVPvC14zHughFwFcraCZVQqShCFsyrx52kxt1i +Zcd0/PgHxDbgQF9bkD1Xthuxvpw6J8ibgSVRU0K0Kuo2Da+PTq1dH8H9BLtj8ynDfNr gc1LPzALp6ZSq4JLzg0sVov7PdbZrEE/aUfqtzRRU2qUUj5HQRq9GUUIxCaUHfN6o5lP H5wUDb/I/zDPSgG543G+funkwG5lw0+cC3PVpj5/TVRjeo2Vmatk2ODnYYanQl8H9xFk b4OHDUuRYSLDIrEC7TGR4wSMZu1IWH8thO7lc+2ixDZPigccpPj4fVy70UhNTBtIc3Uc qpKQ==
X-Received by 10.180.24.3 with SMTP id q3mr21887073wif.24.1442938939927; Tue, 22 Sep 2015 09:22:19 -0700 (PDT)
Content-Disposition inline
In-Reply-To <20150922154520.GM25574@eeg.ccf.org>
User-Agent Mutt/1.5.21 (2010-09-15)
X-detected-operating-system by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value).
X-Received-From 2a00:1450:400c:c05::22e
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>
X-Received-Bytes 3347
X-Received-Body-CRC 1165045127
Xref csiph.com gnu.bash.bug:11546

Show key headers only | View raw


2015-09-22 11:45:20 -0400, Greg Wooledge:
> On Tue, Sep 22, 2015 at 10:19:56AM -0400, idallen@home.idallen.ca wrote:
> > Description:
> > 	Adding a "local" keyword to a variable assignment hides the
> > 	return code of a command substitution.	Same problem in both
> > 	bash and dash shells.
> 
> Yes, this is how it works.  If you care about the return value of a
> command used to initialize a local variable, you have to write it in
> two steps:
> 
> foo() {
>     local foo
>     foo=$(bar) || return
> }
[...]

It also avoids problems with some other shells that support
"local" as a normal command when one forgets to quote the
$(command-subtitution) (where for instance
local foo=$(echo bar baz) is like local foo=bar baz)

Note that for "readonly", the assignment needs to be done first:

foo=$(bar) || return
readonly foo

-- 
Stephane

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


Thread

Re: local keyword hides return code of command substitution Stephane Chazelas <stephane.chazelas@gmail.com> - 2015-09-22 17:22 +0100

csiph-web