use strict;
use warnings;

use Cwd qw(chdir getdcwd);

show_drives();
system("dir/w");
chdir("D:/testdir") or die "Can't change to dir 'D:/testdir' ($!)\n";
system("dir/w");

sub show_drives {
    printf "You are in '%s' on the current drive\n", getdcwd();
    printf "You are in '%s' on the 'D' drive\n",     getdcwd('D');
    print  "\n";
}