#!/usr/bin/perl

# https://perlmonks.org/?node_id=1216436

use strict;
use warnings;

print reverse split /^(?=Title)/m, do{ local $/; <DATA>};

__DATA__
Title 1
Line of text A
Line of text B
Title 2
Line of text C
Title 3
Title 4
Line of text D

[download]

Outputs: 

Title 4
Line of text D
Title 3
Title 2
Line of text C
Title 1
Line of text A
Line of text B

[download]

Which I think is more valid than your Desired Output

In reply to Re: How to reorder a text file by tybalt89
in thread How to reorder a text file by hennesse

Title:
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