Take a look at:153602 (and others)

Type "print columns" into the search box at the top of the screen.

Having had a /msg conversation with mkmcconn, I realised that he is writing this as a Learning Perl exercise and wants critque of his code, rather than a "module solution".

On that basis, I'll let someone with greater expertise than me offer the advice.

It might still be worth downloading the source of some of the module solutions described elsewhere and take a look how they do this. Though I appreciate that the code in some of the modules can be all but indecipherable to non- or only-slightly Perlish eyes:)