[lug] Letting Bash do the Arithmetic

[Kenneth D. Weinert]

	It appears as if the (( )) syntax has to be a "primary"
operator - ie, it only works if the (( operator is the first one on
the line.

	This, however, does work (admittedly there's a cost to it):

head -n $(((23945837-4926402))) some.file

	So it just depends on whether the cost of spawning a shell to
do math is worth it :)

	Oh, just to point out two more possibilites:

	head -n $(echo "23945837 - 4926402"|bc) some.file
	head -n $(echo "23945837 4926402 - p"|dc) some.file

And I'm sure there are other variations with perl, etc, which are
obviously overkill for this particular application, but might come in
handy in other circumstances.

On Tue, Apr 15, 2003 at 01:17:24PM -0600, Sean Reifschneider wrote:
> On Mon, Apr 14, 2003 at 06:28:22PM -0600, Peter Hutnick wrote:
> >So I'm trying stuff like "head -n ((23945837-4926402)) some.file"  and
> >getting "bash: syntax error near unexpected token `('."

-- 
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2 + 2 = 5 for extremely large values of 2.

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