My data is in a PostGIS database. I would like to generate a shapefile from a query. How can I do that?
The recommended way to do this is using the pgsql2shp utility, which should be installed with PostGIS. Note that you must include the geometry column in the query.
If you wanted to save a whole table as a shapefile, just use the table name as the query.
You can also use the ogr2ogr utility, but it has more dependencies so should not be the first option. If you are determined, the equivalent command would be:
Depending on the piece of data you want to export, another way is to use qgis or a similar product : there you open a connection ot postgis and select the data you're interested in; then you save as shapefile...
If you want to export automatically and/or large parts of data, rudivonstaden gave appropriate solutions!