use strict;
use warnings;

use Cwd qw(getcwd chdir getdcwd);

# Here, D:\testdir exists, but C:\testdir does NOT
my $drive = substr(getcwd(), 0, 2);
chdir('C:/testdir') or die "No such directory 'C:/testdir'\n";
chdir($drive);

__END__
Produces:
No such directory 'C:/testdir'