Generic data import and export commands rely on the GDAL/OGR library to be installed correctly. If you have installed GRASS via a binary package, chances are that these commands will work fine. If you have compiled GRASS and GDAL from source, and have not re-compiled GDAL with GRASS support then raster export via r.out.gdal will not work. See this page for details.
The following examples assume that all of the input data has been projected to a consistant coordinate system, and that an appropriate GRASS location has been created. Command names are in boldface type, input files are red, and the resulting GRASS data are in green. Figures are provided for additional context, and are referenced by input/output file name in the example code.
Vector Import
Raster Import
Text File Import
GPS Import