Shell Programming and Scripting

ida, you cannot add files up, you can only work with their content, but I think I understand the direction of your question, so try and see if this works for you and then you can take it from there...

Code:

for file in *u.grd
do
  printf "%s\n" "Now reading from files $file and ${file%u.grd}v.grd and writing to ${file%u.grd}.grd"
  while read f1 && read f2<&3
  do 
    printf "%s\n"  "Do something with $f1 + $f2"
  done < "$file" 3< "${file%u.grd}v.grd" > "${file%u.grd}.grd"
done

NOTE: I have used u.grd and v.grd as the last parts of the files, like you used in the previous post, but if it is still .ugrd and .vgrd then you need to replace u.grd with .ugrd and v.grd with .vgrd everywhere.

Thanks a bunch scrutinizer.