Re: Can Bash do simple math?

[alex xmb sw ratchev]

ah its like array matching .. uh i had nice awk script , ill make new ..

so the % 60 or so code is * 60 ..
weird

a number , big , prolly smaller than bash max ?
then thats already seconds

it implents a ' pseudo 60 ' case
where in end to * 60

i really dont see why 60

about my awk , ill do a math converter
like 123456 is 123t456
i mean convert numbers to multi-stuffix human-readable form

On Tue, Aug 6, 2024, 16:47 Greg Wooledge <greg@wooledge.org> wrote:

> On Tue, Aug 06, 2024 at 16:35:39 +0200, alex xmb sw ratchev wrote:
> > On Tue, Aug 6, 2024, 00:34 <bash@blaklinten.xyz> wrote:
> >
> > > I have a somewhat strange issue.
> > > In a script I use the `((VAR = expression ))` syntax to calculate a
> > > simple remainder by division:
> > >
> > >   ((DIFF = $2 - $1))
> > >   ((SECONDS = DIFF % 60))
> > >   ((MINUTES = (DIFF % 3600) / 60))
> > >   ((HOURS = DIFF / 3600))
> > >
> >
> > just .. what u do diff % 60 , 'SECONDS' it is already .. % 60 ( if it
> > counts as how many 60thiet times ) is minutes already
> > i suppose u mean $2(seconds) -1(seconds) , = seconds
> > if thats not ur case plz explain
>
> The code is converting a (large) number of seconds into a time interval
> expressed as a number of hours, plus a number of minutes, plus a number
> of seconds.
>
> There are a few different ways to perform this calculation.  The most
> straightforward IMHO would be:
>
>  1) Divide the total by 3600 to get the number of hours.
>  2) Decrease the total by (3600*hours).
>  3) Divide the new total by 60 to get the number of minutes.
>  4) Decrease the total by (60*minutes).
>  5) The remaining total is the number of seconds.
>
> The poster is using a slight variant, in which the number of hours and
> the number of seconds are calculated directly from the total, and the
> number of minutes is calculated directly from the total in two steps,
> without modifying the total or introducing an explicit temporary variable.
>
>  1) The number of seconds is the total mod 60.
>  2) The number of hours is the total divided by 3600.
>  3) The number of minutes is computed by first taking the total mod 3600
>     (which removes the whole hours), and then dividing that by 60.
>
> There is an *implicit* temporary variable in step 3, but it's not given
> a name or a formal storage allocation.
>
>