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

while (<DATA>) {
    if (my $flip = /^start/ ... /^[^+]/) {
        print unless $flip =~ /E/;
    }
}

__DATA__
start text
+ 123
+ 456
+ 789
some other text not starting with +


##</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,