Hi Ratnam,
I think you have many options, depending on the needs and complexity of your requirement.
1. You can move the file to another filesystem after processing. For example from the folder .../myjob/files/in to .../myjob/files/processed
2. You can have a detailed log table where you indicate the file name, status (processed, not processed), date and time, etc., before carrying out your process, check the log table against the file name .
3. You can do the above also using a text file, a .csv, etc.
There should be many more options, in any case if your validation detects that the file was processed, you simply use the "Abort" step
Best regards