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Message-ID: <425CB62C.FAF6F5B6@dessent.net>
Date: Tue, 12 Apr 2005 23:03:24 -0700
From: Brian Dessent <brian AT dessent DOT net>
Organization: My own little world...
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To: cygwin AT cygwin DOT com
Subject: Re: Variable not set correctly in bash
References: <86B406A17C3F684CB66499B87361FB3802D8FD AT mail DOT dieball DOT net>
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Andre Dieball wrote:

>                 NEW=$[ $OLD + 1 ]

That construct is a bash extension that is not part of the regular
bourne shell capability.  On linux, /bin/sh is bash, so it works.  On
Cygwin, /bin/sh is ash which is a more basic bourne shell that does not
have all the extra extensions that bash has.  In other words, by doing
that you're limiting your script to only work on bash.  You can either
change the shebang to explicitly call bash, or use a more portable
construct, such as

NEW=`expr $OLD + 1`

Brian

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