The account number is a fixed 9 digits that is always the first 9 digits in 7 of the files. For the remaining files also it is always in a fixed location on each line of the file.
Comment on Re^2: retrieving information from a set of files
I forgot to note 1 additional comment: the number of fields may vary according to the file. Although my sample data illustrates only 3 columns, this is not true for the files I have.