How do I return a variable in GRASS GIS on a Windows machine?

For example I set a list of files to define my region. I already figured out that I can't use the bash command export, I need to use set instead. The command should be okay, but it doesn't return $MAPS.

set MAPS=`g.mlist type=rast sep=, pat="*"`  
g.region rast=$MAPS -p

I tried already to check if the variable is set (echo $MAPS), but without success.

  • 1
    Those back ticks are linux syntax to evaluate what's inside of them first. It won't work on windows to capture output in a variable. This is a frustrating problem I've faced a lot too. The best I've been able to find is something like FOR /F "delims=" %i IN ('echo "Hello World"') DO set output=%i then echo %output% gives "Hello World" from stackoverflow.com/questions/108439/…. But it's so cumbersome that at this point I usually switch to python. Hopefully you get a good answer because I'd like to see it too.
    – user55937
    Commented Sep 2, 2015 at 13:11
  • 1
    Thx @user55937, I think I will give up and switch back to Linux... It's just too frustrating.
    – wittich
    Commented Sep 3, 2015 at 14:35

1 Answer 1


That's because $MAPS doesn't exist from windows command line.

You need to call variables with %MAPS% (surrounded by % sign).

But also consider that grass when installed either from the grass site using the stand alone installer or osgeo4w they both come with MSYS - a unix like shell. You can use that instead which lets you stay with bash like syntax.

  • It doesn't work, I tried a echo %MAPS% and it returns just the variable name. I'll try to use MSYS that sounds like a what I want...
    – wittich
    Commented Sep 3, 2015 at 7:20
  • It seams like cmd is not fully loaded. If I set set test=123 and let it return directly echo %test% it just print %test%. Normally it only does that in cmd when the variable is not set. By the way with MSYS I can't run grass64, it seem like something is wrong implemented. Maybe I should reinstall OSGeo4W or just switch into the virtual machine.
    – wittich
    Commented Sep 3, 2015 at 14:32

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