sundialsvc4:
You folks seriously told the OP to “de-parse” a Perl subroutine into its underlying bytecode-tree, assuring him or her that thereby it would be “obvious?” Really?? ... :-/ ... Gee, you people really are nerds!
The one and only thing to remember about seek(), in any programming language at all, is that it works strictly on byte-positions within the file. It does not know about newline sequences (in any of their one- or two-byte flavors ...), nor does it know about Unicode. The file consists of nothing more and nothing less than a collection of zero-or-more bytes, and seek() sets the read/write cursor to an absolute or relative byte position within that collection.
Poor flushells, you really don't know anything about B::Deparse, print, $/, -l
Why starts at "column 0"? Why 78/80? Because \r\n is added