while read n ; do
  echo $n;
  latmax=$(echo $n | cut -d ',' -f 2);
  latmin=$(echo $n | cut -d ',' -f 3);
  lonmax=$(echo $n | cut -d ',' -f 4);
  lonmin=$(echo $n | cut -d ',' -f 5);
  cdo -f nc sellonlatbox,${lonmin},${lonmax},${latmin},${latmax} -topo outfile$(echo $n | tr ',' '_').nc ;
done < coordextended2.csv