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Date: Thu, 14 Aug 2003 13:01:26 -0500
From: Dan Nelson <dnelson@allantgroup.com>
To: Richard Tobin <richard@cogsci.ed.ac.uk>
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References: <200308141742.SAA17915@rhymer.cogsci.ed.ac.uk>
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cc: Charles Howse <chowse@charter.net>
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Subject: Re: Using bc in bash script
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In the last episode (Aug 14), Richard Tobin said:
> > I'm trying to calculate the number of seconds between $start_time and
> > $end_time in a bash script.
> 
> Bash has built-in integer arithmetic:
> 
>   et=$[End_time - Start_time]

Most bourne-based shells have arithmetic evaluation.  For portability,
you should use the $(( )) syntax:

/bin/sh
$ echo $(( 1 + 3 ))
4
$

-- 
	Dan Nelson
	dnelson@allantgroup.com