use Cwd; my $path = cwd;
Probably better this way, so the reader will know where each function comes from and we reduce the risk of redefining other functions by importing exactly the functions we want.
use Cwd ('cwd'); my $path = cwd;
also written as
use Cwd qw(cwd); my $path = cwd;
You can also make sure not to import anything and the use fully qualified names.
use Cwd (); my $path = Cwd::cwd;