You can also use let, which may make more sense
let "myVar=$myVar+1"
As for floating point you need something like bc to handle that
myVar=5.4
myOtherVar=3.1
myVar=$(echo "scale=2; ($myVar + 3.14) / $myOtherVar" | bc)
echo $myVar
If ran the above would print 2.75
On Mon, Mar 2, 2015 at 7:15 PM, der.hans <
PLUGd@lufthans.com> wrote:
> Am 02. Mär, 2015 schwätzte Michael Havens so:
>
> moin moin Mike,
>
> see the Arithmetic Expansion portion of the bash man page for details.
>
> $((expression))
>
> That says to evaluate the expression and substitute the result. Remember
> that the shell only does interger math, no decimals.
>
> :) ~$ echo $(( 4 / 2 ))
> 2
> :) ~$ echo $(( 4 / 3 ))
> 1
> :) ~$ echo $(( 4 * 3 ))
> 12
> :) ~$
>
> Note that you don't need to escape the * when using arithmetic expansion
> because the $(( )) is already quoting.
>
> ciao,
>
> der.hans
>
>
> just starting with this so please, bear with me....
>>
>> Anyways I am looking at this beginner's script:
>>
>> #! /bin/bash
>> myvar=0
>> while [ $myvar -ne 20 ]
>> do
>> echo $myvar
>> myvar=$(( $myvar + 1 ))
>> done
>>
>> Now my mind can wrap itself around everything in this script except for
>> tis
>> line:
>>
>> myvar=$(( $myvar + 1 ))
>>
>> Where my difficulty arises is why the '$' before the '(('?
>> (it was geast fun running that script with a minus sign instead!)
>> :-)~MIKE~(-:
>>
>>
> --
> # http://www.LuftHans.com/ http://www.PhxLinux.org/
> # "The first requisite of a good citizen in this republic of ours is that
> # he should be able and willing to pull his weight." -- Theodore
> Roosevelt
> ---------------------------------------------------
> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org
> To subscribe, unsubscribe, or to change your mail settings:
> http://lists.phxlinux.org/mailman/listinfo/plug-discuss
>
---------------------------------------------------
PLUG-discuss mailing list -
PLUG-discuss@lists.phxlinux.org
To subscribe, unsubscribe, or to change your mail settings:
http://lists.phxlinux.org/mailman/listinfo/plug-discuss
(text/plain)