#! /usr/bin/perl
use warnings;
use strict;

my $text = << '__TEXT__';
SECTION 1

This is the first section.

SECTION 2

And this is
the second one.
__TEXT__

my %section = ("", split /(SECTION \d+)/, $text);
delete $section{""};
use Data::Dumper; print Dumper \%section;