#!usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
use List::Compare;
use File::Find::Rule;

sub get_files {
    my @dirs = ('/home/tinyos/Monks/uniq');
    my $level = shift // 2;

    my @files = File::Find::Rule->file()
    ->name('*.txt')
    ->maxdepth($level)
    ->in(@dirs);

    return @files;
}

my @files = get_files();

# print Dumper \@files if @files;

# file to compare against the rest
my $path2compare = '/home/tinyos/Monks/uniq/compare.txt';
open my $fh, '<', $path2compare
    or die "Can't open file $path2compare: $!";
chomp(my @array2compare = <$fh>);
close $fh
    or warn "File $path2compare close failed: $!";

# open files and load them into an array
# compare unique lines and store them into a Hash of Arrays
my %HoA;
foreach my $path_to_file (@files) {
    open my $fh, '<', $path_to_file
	or die "Can't open file $path_to_file: $!";
    chomp(my @lines = <$fh>);
    close $fh
	or warn "File $path_to_file close failed: $!";
    my $lc = List::Compare->new('-u', \@array2compare, \@lines);
    # Get those items which appear at least once in both lists (their intersection).
    my @intersection = $lc->get_intersection;
    # Get those items which appear (at least once) only in the second list.
    # my @Ronly = $lc->get_complement;
    # print Dumper \@Ronly;
    # write to file here
    $HoA{$path_to_file} = \@intersection;
}

print Dumper \%HoA;

__END__

$ perl unique.pl
$VAR1 = {
          '/home/tinyos/Monks/uniq/compare.txt' => [
                                                     'Common line',
                                                     'Unique line file Original'
                                                   ],
          '/home/tinyos/Monks/uniq/unique1.txt' => [
                                                     'Common line'
                                                   ],
          '/home/tinyos/Monks/uniq/unique2.txt' => [
                                                     'Common line'
                                                   ]
        };

uniqu1.txt
Unique line file1
Common line

uniqu2.txt
Common line
Unique line file2

compare.txt
Unique line file Original
Common line