Date: Fri, 15 Aug 2014 01:55:59 +0000 From: Cary <cary@SDF.ORG> To: Warren Block <wblock@wonkity.com> Cc: Rick Miller <vmiller@hostileadmin.com>, FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: /bin/sh script not behaving as expected Message-ID: <20140815015559.GA21249@SDF.ORG> In-Reply-To: <alpine.BSF.2.11.1408141143010.53473@wonkity.com> References: <CAHzLAVE1E8hZvZEnDko8-7cfx6JYypezi3oxs4vKKjxDzSzZnw@mail.gmail.com> <alpine.BSF.2.11.1408141143010.53473@wonkity.com>
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On Thu, Aug 14, 2014 at 11:51:53AM -0600, Warren Block wrote:
> On Thu, 14 Aug 2014, Rick Miller wrote:
>
> >Hi all,
> >
> >I have shell code whose purpose is to determine the first disk in the
> >system where FreeBSD is to be installed. The code is not behaving as
> >expected and I?m hoping that fresh pairs of eyes might help me identify the
> >problem.
> >
> >Here is the script along with an explanation of the implementation and
> >description of the problem:
> >
> >#! /bin/sh
> >
> >disks="da2 da1 da0";
> >
> >for d in ${disks}; do
> > if [ -z "${disk}" -o "${disk}" '>' "${d}" ]; then
> > : ${disk:=${d}};
> > fi
> >done
>
> The algorithm is not clear to me,
Nor me.
Rick, I don't understand the test. Would just
if [ -z "${disk}" ]; then
suffice ? Single-quoting the > operator looks like an error that would have
prevented the shell from executing the script.
> but I would do something simpler like
>
> disk=`cd /dev; ls da? | head -n1`
>
> or, more correctly,
>
> disk=`sysctl -n kern.disks | tr " " "\n" | sort | head -n1`
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--
cary@sdf.org
SDF Public Access UNIX System - http://sdf.org
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