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

while (<DATA>) {
    if (my $flipflop = /start/ .. /end/) {
        print "$flipflop: $_";
    }
}

__DATA__
before
start
1
2
3
end
after


##</code><code>##

1: start
2: 1
3: 2
4: 3
5E0: end


##</code><code>##

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,