Vlad,
Idealy, I'd like to get all Field 5 from File_1.dat and File_2.dat. I noticed that something worng with the following code since it always gives me the same NDC11[$2] -- the Field 5 of File_1.dat.
$1 == "F" && length(NDC11[$2])>0 {
print $2 , NDC11[$2], $5
}
To answer your...