Date: Thu, 4 Apr 2002 00:06:21 +0300 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: Glenn Johnson <gjohnson@srrc.ars.usda.gov> Cc: questions@freebsd.org Subject: Re: why does this test condition not work? Message-ID: <20020403210621.GH848@hades.hell.gr> In-Reply-To: <20020403172111.GA88600@node1.cluster.srrc.usda.gov> References: <20020403172111.GA88600@node1.cluster.srrc.usda.gov>
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On 2002-04-03 11:21, Glenn Johnson wrote:
> I am writing a script am am trying to prompt for input and make sure all
> of the values are entered. I have the following test condition in my
> script but when I run it I get:
>
> [: -z: unexpected operator
> while [ -z $tor1a -o -z $tor1b -o -z $tor1c -o -z $tor1d ]
> do
> read -p "Enter the atom numbers of the first torsion: " tor1a
> tor1b tor1c tor1d
> done
Because at first all of your variables are unset, and the test within
brackets is expanded by sh to:
[ -z -o -z -o -z -o -z ]
The first -o is consumed by the previous -z, and then test(1) moves on
to check the rest of it's arguments and finds a -z (the second -z)
where it would expect -or or -and.
Try this instead:
while [ -z "$tor1a" -o -z "$tor1b" -o -z "$tor1c" -o -z "$tor1c" ]
do
echo -n "Enter the atom numbers of the first torsion: "
read tor1a to1b tor1c tor1d
done
Giorgos Keramidas FreeBSD Documentation Project
keramida@{freebsd.org,ceid.upatras.gr} http://www.FreeBSD.org/docproj/
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