What is the best way to process a fixed-length flat file?

The interviewer is asking you this operational question to make sure you know how to perform this process. Your response should be in the form of a step-by-step description of what you would do to accomplish this task. You don't need to get too technical or provide too many details. The interviewer will ask a follow-up question if they need more information.

"A fixed-length file layout should include the file name, where the field begins, its length, and its data type, which will usually be text or number. You only need to supply those layout information once. The tool will remember this and expect a similar format for subsequent fixed-length flat files. Data validation is essential in this process in case the format of the data has changed. The most likely change will occur if the data includes a date field."