#!/usr/bin/perl
use strict;
use warnings;
my $path = 'C:\folder1\folder2\';

my @newName = split (/\\/, $path);
shift(@newName);
my $rename = join(".", @newName);

opendir (my $directory, $path) or die $!;
while(readdir $directory) 
    {
       
        next if $_ =~ m/^\./;
        my $fileName = "$rename" . ".$_";
        rename $_, $fileName;
    }