Re: Can Bash do simple math?

[alex xmb sw ratchev]

~ $ alias tm='timemark+=( $EPOCHREALTIME )'
tm ; sleep .313373 ; tm IFS=- ;

[Process completed (signal 11) - press Enter]

( two lines , one alias , one rest )

On Tue, Aug 6, 2024, 18:32 alex xmb sw ratchev <fxmbsw7@gmail.com> wrote:

> also btw for preciese timings
> u need float math
> like with awk
>
> two methods
>
> use date +%s.%N
>
> or inline script
> do
> timemarker+=( $EPOCHREALTIME )
> on beginning
> and end
> and math together , like
>
> awk '{
>
> .. i was writing
> any idea why following exits android termux ? andro kill policy ?
>
> ~ $ alias tm='timemark+=( $EPOCHREALTIME )'    ~ $ tm ; sleep .313373 ; tm
> ; IFS=- ; gawk ' { print ( $0 ) } ' <<<"${timemark[*]: -2:2}"
> Vim: Caught deadly signal 'SIGTERM'
>
> [Process completed (signal 11) - press Enter]
>
> On Tue, Aug 6, 2024, 18:24 alex xmb sw ratchev <fxmbsw7@gmail.com> wrote:
>
>>
>>
>> On Tue, Aug 6, 2024, 17:53 Greg Wooledge <greg@wooledge.org> wrote:
>>
>>> On Tue, Aug 06, 2024 at 17:08:23 +0200, alex xmb sw ratchev wrote:
>>> > i really dont see why 60
>>>
>>> Because there are 60 seconds in each minute, and 60 minutes in each hour.
>>>
>>> Let's say you measure how long a program takes to run, and it ends up
>>> being 179 seconds.  You'd like to convert this number (179) to an
>>> interval expressed as "x minutes and y seconds".
>>>
>>> There are a few ways you can do this.  They all give you the same answer.
>>>
>>> The way that I find simplest to understand is always to divide by the
>>> next conversion factor.  So:
>>>
>>>  1) We divide 179 by 60, to get the number of minutes.
>>>
>>
>> u misread big
>> the users original code
>> makes , seconds minus math
>> the currency of it is still 1second
>>
>> now look what u write
>> ' to get minutes '
>>
>> i say users code has
>> seconds = diffinseconds % 60
>> not
>> minutes = diffinseconds % 60
>>
>> i use / 60 anyway
>> i must benchmark somewhen
>>
>>     We're using integer division, so any fractions are discarded.
>>>     179 / 60 = 2
>>>     So the final answer includes "2 minutes" as the first component.
>>>
>>>  2) Now that we know how many whole minutes there are, we remove those
>>>     from the original number.
>>>     2 * 60 = 120
>>>     We decrease the original number by 120.
>>>     179 - 120 = 59
>>>
>>>  3) The amount that's left over (59) is the number of seconds.
>>>     So our final answer is "2 minutes and 59 seconds".
>>>
>>> The conversion that the OP used is very similar to this, except they
>>> went for hours, minutes and seconds.
>>>
>>> Let's say you run a different program and it takes 7701 seconds, and
>>> you'd like to convert this to "x hours, y minutes and z seconds".  We
>>> can apply a similar recipe:
>>>
>>>  1) Divide 7701 by 3600 to get the number of whole hours.
>>>     7701 / 3600 = 2
>>>     "2 hours"
>>>
>>>  2) Subtract the whole hours from the original number.
>>>     7701 - (2 * 3600) = 501
>>>
>>>  3) Divide by 60 to get the number of minutes.
>>>     501 / 60 = 8
>>>     "8 minutes"
>>>
>>>  4) Subtract the whole minutes from the original number
>>>     501 - (8 * 60) = 21
>>>
>>>  5) The remaining number is the number of seconds.
>>>     "21 seconds"
>>>
>>> So in this case, our final answer is "2 hours, 8 minutes and 21 seconds".
>>>
>>> The OP chose to use slightly different recipes, which involve modulus
>>> and which don't decrease the total as we go.  That's fine.  As I said,
>>> there are different ways to do it, which all give the same answer.
>>>
>>>