in reply to print source golf

> Why does it do that?

readline in list context.

FWIW 

use strict;
use warnings;

seek DATA,0,0;
print scalar <DATA>;
__DATA__

[download]
prints

use strict;

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

In Section Seekers of Perl Wisdom