To mirror a website and do some sophisticated FTP commands, check out [[http://lftp.yar.ru/|lftp]] \\
To mirror a directory, cd to local directory first and then do the following:
<code>
$ lftp username@server.domain
lftt> cd <directory_as_appropriate>
lftp> mirror -R -e -v -n (use --dry-run to just list files)
</code>
-R puts files from local machine to remote machine \\
-e deletes files on remote machine that aren't on local machine \\
-v is verbose mode \\
-n transfers only new files \\

Other tips: \\
[[http://tutorials.papamike.ca/pub/lftp.html]]