> Parsing tab-, comma-, whatever-separated files has various issues that have already been dealt with by Text::CSV

Like what?

That module deals with all the features and intricacies of the 'official' CSV format, such as quoting/escaping and embedding newlines/NULLbytes. But the OP never specified the input data be in that complex format; from the looks of it it's just simple ASCII strings delimited by tabs and newlines. No need to take a sledgehammer to crack a nut...

> This is probably not a wheel you need to reinvent

Applying a simple, tried-and-true Perl idiom is not much of an 'invention':