The script for the sake of simplicity will add a trailing 'z' to all files and directories... As far as a reason why I am not using File::Find the reason would be ignorance

Then perhaps this will help to rectify that:

use File::Find;

sub rename_file {
  my $fullpath = $File::Find::name;
  rename ($fullpath, $fullpath.'z') || 
         warn "Failed to rename $fullpath\n";
}

find (\&rename_file, $path);
[download]

What could be simpler?

As others have pointed out, modules are there to help you. Not using them out of ignorance is probably not what you want to do for too long: you miss out on all the fun!