Could you give an example of data the two files might contain and tell us which records you would like to keep when you merge the files? Maybe you want to keep records that match in some way or maybe you want to eliminate duplicates?
file one:
part_number, table
file two:
part_number, stock, lead_time, etc.
I assuming that the number of lines in the two files doesen't match and I only want a file three with the same part numbers as in file two.
\Sorenjul