#!/usr/bin/env perl

use 5.010;
use strict; use warnings;

my $in_toc = 1;     # we start off in the Table of Contents
my $in_ch2 = 0;
while (<>) {
    $in_toc = 0 if /^\s*=+\s*$/;
    next if $in_toc;
    $in_ch2 = 0 if /^Chapter 3/;
    say if $in_ch2;
    $in_ch2 = 1 if /^Chapter 2/;
}