$ pgsql2shp -f <path to output shapefile> -h <hostname> -u <username> -P <password> databasename "<query>"

$ pgsql2shp -f qds_cnt -h localhost -u postgres -P password gisdb "SELECT sp_count, geom FROM grid50_rsa WHERE province = 'Gauteng'"

Initializing...
Done (postgis major version: 2).
Output shape: Polygon
Dumping: XXXXXXXXXXXXXXXXXXXX [1947 rows].

$ ogr2ogr -f "ESRI Shapefile" qds_cnt.shp PG:"host=localhost user=postgres dbname=gisdb password=password" -sql "SELECT sp_count, geom FROM grid50_rsa WHERE province = 'Gauteng'"

$ pgsql2shp -f qds_cnt -h localhost -u postgres -P password gisdb "Select sp_count, geom from grid50_rsa where province = 'Gauteng'"

$ pgsql2shp -f qds_cnt -h localhost -u postgres -P password gisdb "SELECT sp_count, geom FROM grid50_rsa WHERE province = 'Gauteng'"