Re: [SLUG] Command help

From: Eben King (eben1@tampabay.rr.com)
Date: Sun Feb 12 2006 - 15:57:30 EST

On Sun, 12 Feb 2006, Ian Blenke wrote:

> Bob Stia wrote:
>> Hello Sluggers,
>>
>> What is wrong with the following command? Trying to figure out how much to
>> shrink down a movie.m2v Not a bash command?
>>
>> EasyStreet:/backup # factor = (6423971301/ (4600000000. - 232415232 ) ) *
>> 1.04
>> bash: syntax error near unexpected token `('
>> EasyStreet:/backup #
>>
>
> If you have integers (not floats), you can do the following:
>
> #!/bin/bash
> (( factor = 6423971301/ (4600000000 - 232415232 ) ))
> echo $factor

There can't be spaces around the "=" in "foo=bar", I don't think. Unless
that's a different environment.

> There's probably another way to handle floats, but this is what I'd probably
> end up doing:
>
> factor=$( echo 'scale=2; (6423971301/ (4600000000. - 232415232 ) ) * 1.04'
> | bc )
>
> Using bc is a bit of cheating, but it's quick and dirty, and it works.

Yeah, but I'd use dc. Same idea.

> The "scale=2" means that you want two places to the right of the decimal.

What do you want, the scale of a 6.4*10^10^9 byte movie to fit it and
232*10^6 bytes of other stuff to fit them both on a 4.6*10^9 byte DVD?

room=$(( 4600000000 - 232415232 ))
scale=$(( ( room * 100 ) / 6423971301 ))
echo "${scale}%"

Decimals are a PITA in bash. 

-- 
-eben    ebQenW1@EtaRmpTabYayU.rIr.OcoPm    home.tampabay.rr.com/hactar

           Q: What kind of modem did Jimi Hendrix use?
           A: A purple Hayes.
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