use strict;
use warnings;
use File::Copy;
use Cwd;

my $home_dir = getcwd;
$home_dir = "$home_dir/files";

opendir DIR, $home_dir; 
my @org_files = grep "$home_dir/$_",readdir DIR; 
closedir DIR; 

for my $new_files(@org_files)
   {
    $new_files =~ s/2005/2006/g;
    print $new_files,"\n";
   }