Re: Efficiency of FTP URLs

Joe English (
Mon, 25 Jul 1994 15:02:36 -0700

Marc VanHeyningen <> wrote:
[ re: leaving FTP control connections open between transactions ]
> Real problem with "leave it open" is how to deal with relative paths
> that back up or absolute paths that aren't the same. There's no
> general way to CWD up a directory or to go back to the FTP root other
> than to break the connection and re-establish it.

RFC 959 does include an optional 'CDUP' command to
change to the parent directory. I don't know how many
non-Unix servers support it, though I seem to recall
it working on at least one Mac FTP server I've talked to.

Then again, even CDUP won't work in all cases (e.g.,
multiple symbolic links to a directory.)

--Joe English