local $/ = undef;
my $record = <INPUT>;
my @chunks = split /regex/ , $record;
for my $chunk ( @chunks ) {
    my @lines = split /\n/ , $chunk;
}

##</code><code>##

local $/ = undef;
my $record = <INPUT>;
my @chunks = split /(regex)/ , $record;
while ( @chunks ) {
    my $header = shift;
    my $chunk = shift;
    my @lines = split /\n/ , $chunk;
}