Hi, I am pasting a snippet of my code.

For future reference, as How (Not) To Ask A Question would say, you should clean your room :) write a small program to demonstrate your problem and include sample data :)

The issue is only the data of the last file_name is getting saved.How do I fix it?

Three possibilities

• all the filenames are the same filename (your data is bonkers)
• $filename is empty (your regex is failing)
• something else in your code obliterates $filename or something :)

As Basic debugging checklist suggests, if you sprinkle warn "filename($filename) "; at various points in your code, maybe even a Dump, you can pinpoint where your assertions fail.