use strict;
use warnings;
use File::Find;
use File::Slurp qw/read_file/;

my $startDir = '.';
my %dirLines;

find( { wanted => \&countLines, }, $startDir );

for my $dir ( sort keys %dirLines ) {
	my $sameResults = sameArrayElements( @{ $dirLines{$dir} } );

	print "The files in directory '$dir' do"
	  . ( $sameResults ? '' : ' not' )
	  . " have the same number of lines.\n";
}

sub countLines {
	/\.txt$/ or return;

	#my $completePath = $File::Find::name;
	my $curDir  = $File::Find::dir;
	my $curFile = $_;

	my @fileLines = read_file $curFile;
	my $numLines  = @fileLines;

	push @{ $dirLines{$curDir} }, $numLines;

	#say "Cur dir: $curDir; Cur file: $curFile; Num Lines: $numLines";
}

sub sameArrayElements {
	my %hash = map { $_ => 1 } @_;
	keys %hash == 1 ? 1 : 0;
}

##</code><code>##

push @{ $dirLines{$curDir} }, $numLines;

##</code><code>##

$VAR1 = {
          './test/test bbb' => [
                                 6,
                                 6,
                                 6,
                                 6
                               ],
          './test' => [
                        6,
                        2,
                        6,
                        1
                      ],
          '.' => [
                   6,
                   2,
                   6,
                   10000,
                   1,
                   63,
                   10,
                   15,
                   6,
                   21,
                   647,
                   10,
                   5,
                   28,
                   407,
                   2390,
                   11,
                   6,
                   513,
                   181,
                   1,
                   2,
                   360,
                   3
                 ]
        };

##</code><code>##

for my $dir ( sort keys %dirLines ) {
    my $sameResults = sameArrayElements( @{ $dirLines{$dir} } );

...

##</code><code>##

The files in directory '.' do not have the same number of lines.
The files in directory './test' do not have the same number of lines.
The files in directory './test/test bbb' do have the same number of lines.