gdal_proximity.py --version (return code: 0)
GDAL 2.2.1, released 2017/06/23
gdal_proximity.py -HELP (return code: 1)
gdal_proximity.py srcfile dstfile [-srcband n] [-dstband n]
[-of format] [-co name=value]*
[-ot Byte/Int16/Int32/Float32/etc]
[-values n,n,n] [-distunits PIXEL/GEO]
[-maxdist n] [-nodata n] [-use_input_nodata YES/NO]
[-fixed-buf-val n] [-q]