Ofcourse I'm just being lazy by pasting Net::FTP's POD but you started it :)

       cwd ( [ DIR ] )
           Attempt to change directory to the directory given in
           $dir.  If $dir is "..", the FTP CDUP command is used
           to attempt to move up one directory. If no directory
           is given then an attempt is made to change the
           directory to the root directory.
[download]

Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.