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Re: Recomended tutoial(s) on doing arithmetic in Bash scripts

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On 03/05/2017 12:10 PM, Richard Owlett wrote:
> On 03/05/2017 10:25 AM, tomas@tuxteam.de wrote:
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> On Sun, Mar 05, 2017 at 09:42:16AM -0600, Richard Owlett wrote:
>>> I'm interested in "expr" and "bc".
>>> The man pages lack reasonable examples.
>>> The tutorial/HOWTO pages confuse the issue with fancy page layouts
>>> and/or code samples showing how impressive the author can make the
>>> script's output.
>> [snip]
>>
>> If you need floating point numbers, bc (or dc) are your next stops.
>
> Actually  dc is the solution.
> I date from Byte's FORTH issue. Benn a fan ever since.
>>
>> Perhaps you start with a couple of small examples on what you want
>> to achieve, post them here and we take them as riddles :-)
>
> How about the whole app <grin>
> You solved my problem with one line.
> The so called tutorial on dc went to great length to make it look like
> paper coming out of a desk calculator that it obliterated any
> information. Discouraged me from even looking at the man page.
>
>>
>> Here's a little example with dc, [snip]
>>
>> If you wanted to catch the value instead of printing it right away,
>> you would do
>> fill=$(dc -e "5k $NOW $FULL / p")
>
> That's the hint I needed <*GRIN*>
>
> I needed to report the number of bytes downloaded for each portion of a
> project. My 1st pass is below. [I messed up something when I tried to
> divide by 1024 to get kb. Symptom was I somehow had a bad value on the
> stack]
>
>
> mystring=$(echo $(grep "usb0" /proc/net/dev))
> read -r -a myarray <<<$mystring
> owl1=${myarray[1]}
> echo $owl1
>
> # insert process to be measured
>
> mystring=$(echo $(grep "usb0" /proc/net/dev))
> read -r -a myarray <<<$mystring
> owl2=${myarray[1]}
> echo $owl2
> bytes=$(dc -e "1k  $owl2 $owl1 - p ")
> echo "You have just downloaded " $bytes " bytes"
>
> Someone on another group wanted me to use LibreOffice Calc ;/
>

<UGH> silly me had omitted a required SWAP.
Wonder why FORTH purists say even simplest code can benefit from stack 
comments ;>

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Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 16:50 +0100
  Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Reco <recoverym4n@gmail.com> - 2017-03-05 17:30 +0100
  Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-05 17:30 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-05 19:20 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-05 21:40 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Greg Wooledge <wooledg@eeg.ccf.org> - 2017-03-06 14:40 +0100
        Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-06 15:00 +0100
        Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Jörg-Volker Peetz <jvpeetz@web.de> - 2017-03-06 16:00 +0100
          Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-06 16:40 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 19:20 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 19:50 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-05 21:30 +0100
        Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 22:00 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Jude DaShiell <jdashiel@panix.com> - 2017-03-05 23:20 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-06 12:20 +0100
        Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-06 12:40 +0100
  Re: Recomended tutoial(s) on doing arithmetic in Bash scripts David Christensen <dpchrist@holgerdanske.com> - 2017-03-05 20:50 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Richard Owlett <rowlett@cloud85.net> - 2017-03-05 21:50 +0100
      Re: Recomended tutoial(s) on doing arithmetic in Bash scripts David Christensen <dpchrist@holgerdanske.com> - 2017-03-06 04:40 +0100
    Re: Recomended tutoial(s) on doing arithmetic in Bash scripts <tomas@tuxteam.de> - 2017-03-05 22:30 +0100
  Re: Recomended tutoial(s) on doing arithmetic in Bash scripts Jude DaShiell <jdashiel@panix.com> - 2017-03-05 23:10 +0100

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