use strict;

open(IN, "<", "data.txt");
my @in = <IN>;
close(IN);

open(OUT, ">", "out.txt");
my $out = "";   
foreach my $in (@in) {
    chomp($in);
    if ($in =~ m/^(.*?)\\(.*?)\s*$/) {
        $out .= " $2";
    } else {
        if ($out ne "") {
            print OUT "$out\n";
        }
        $in =~ m/^(.*?)\s*$/;
        $out = $1;
    }
}
print OUT "$out\n";
close(OUT);

##</code><code>##

$source{_source}->[0]

##</code><code>##

$source{_source}->[0][0]#dedicate 0 to myself

##</code><code>##

$source{_source}->[0][1]#my 1st child

##</code><code>##

use Data::Dumper;

use strict;

my %source;
$source{_source} = [];
$source{_source}->[0] = [];
$source{_source}->[0][0] = "section1";#myself
$source{_source}->[0][1] = "section11";#1st child
$source{_source}->[0][1] = "section12";#2nd child

print Dumper(\%source);