open my $fh, '>', 'junk.dat' or die $!;

for ( 1 .. 4 ) {
    seek $fh, $_ * 80, 0;
    print $fh $_ x 78, "\r\n";
}

open $fh, '<', 'junk.dat' or die $!;

while ( <$fh> ) {
    use Devel::Peek;
    Dump $_;
}