I no longer have the exact code, but it was along the lines of:

use IO::File;

my $file = IO::File->new(">carddb.txt") or die $!;
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And further down, where it says print STDERR $result; it read $file->print($result) or die $!;.

Ultimately, there was also a $file->close; at the end of the file too.

And thank you for the reminder about LWP::Simple::get_store, but I didn't actually want to keep the whole page.