use strict;
use Fcntl ':mode';

my $dir = "C:\\folder";
my $file = "c:\\test.txt";
my $mode;

$mode = (stat($file))[2];
print "Is '$file' a folder? " . S_ISDIR($mode) ? "Yes" : "No";
$mode = (stat($dir))[2];
print "Is '$dir' a folder? " . S_ISDIR($mode) ? "Yes" : "No";