use Cwd;

$dir = cwd();           # get current working directory safest way



$dir = getcwd();        # like getcwd(3) or getwd(3)



$dir = fastcwd();       # faster and more dangerous



use Cwd 'chdir';        # override chdir; keep PWD up to date

chdir "/tmp";

print $ENV{PWD};        # prints "/tmp"

