[GRASS-user] how to store results from r.sum with script

[Vaclav Petras]

Try remove spaces from r.sum command output (e.g. using `sed`) and since
the results is

SUM=16116.500006

which is valid bash variable definition, you can use `eval` command which
will define the variable, so you can use it afterwards.

$ eval $(echo "SUM = 16116.500006" | sed -e "s/ //g")
$ echo $SUM
16116.500006

I assume from what you have written that `r.sum rast=map at mapset` prints

SUM = 16116.500006

to standard output. Knowing what is the output of that module is crucial.
What module is this, do you have documentation? GRASS modules (in GRASS
distribution) use the convention that if you use `-g` flag they print the
variables in "shell script style", so you can use the output in eval
function or parse it easily. They output would be

SUM = 16116.500006


On Mon, Jan 13, 2014 at 10:20 AM, BLANDENIER Lucien <
lucien.blandenier at unine.ch> wrote:

> Hello Vaclav,
>
> I tried with the following script:
>
> $C=$(r.sum rast=map at mapset)
> $echo $C
> SUM = 16116.500006
>
>
> But I think the variable C stores all the command (r.sum rast=map at mapset)
> and not only the result. Do you know how it would be possible to store the
> result "SUM = 16116.500006"
>
>
> Regards
>
> Lucien
>
>
> ________________________________
> De : Vaclav Petras [wenzeslaus at gmail.com]
> Envoyé : dimanche 12 janvier 2014 03:11
> À : BLANDENIER Lucien
> Cc : grass-user at lists.osgeo.org
> Objet : Re: [GRASS-user] how to store results from r.sum with script
>
> Hi,
>
> I might missed it but I don't know about r.sum module. (I know only r.sun).
>
> Saving standard output of module (if it prints something to standard
> output) is the same as for any other command line tool in bash. If the
> output is a map (in GRASS) just use it as input to some other module (using
> the map name).
>
> Examples bellow show saving outputs of echo command to variables (echo
> command just print its parameters to standard output, i.e. to command
> line). Working with numbers (additions, multiplications) can be more
> difficult (requires different syntax) but there should be some online
> guides.
>
> Vaclav
>
>
> $ A="some text"
> $ echo $A
> some text
>
> $ B=`echo "this is printed to stdout"`
> $ echo $B
> this is printed to stdout
>
> $ C=$(echo "this is printed to stdout")
> $ echo $C
> this is printed to stdout
>
> (lines beginning with $ are lines with command which are meant to by typed
> into the command line, the other lines are output)
>
>
> On Sat, Jan 11, 2014 at 9:32 AM, BLANDENIER Lucien <
> lucien.blandenier at unine.ch<mailto:lucien.blandenier at unine.ch>> wrote:
> Dear all,
>
> I would like to know if there is a way to store results of a calculation
> done with r.sum on many raster with a bash script.
>
> I need to reuse these results in later calculations.
>
> Thanks
>
>
> Lucien
>
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>
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