ftp:// error

tony at servacorp.com tony at servacorp.com
Fri Dec 2 22:37:55 GMT 2005

hashproduct at verizon.net wrote:
>On Fri, 2005-12-02 at 17:41 +0000, Manuel
>López-Ibáñez wrote:
>> I am sorry, the rsync algorithm needs to execute
>rsync on the server. 
>> Since ftp does not allow executing remote
>programs (as ssh does), even 
>> if there exists a rsync executable installed in
>the server and you have 
>> permission to execute it, using ftp you cannot
>execute it. So your 
>> command won't work and it will never be because
>it is impossible to 
>> implement it by the very differences of what
>rsync does (executing a 
>> remote rsync program) and how ftp works (just
>download files).
>In my opinion, that's a perfect explanation.
>However, Marten is probably far from the only
>person who would love to
>use rsync over an FTP connection.  Its flexibility
>has to surpass that
>of just about every tool that does support FTP. 

However, due to stuff like limited firewalls on either side, DOS/UNIX/MAC text files, FTP does not always support FTP. I doubt that rsync can/should fill in the missing gaps.

Rsync's dominant advantage is when there is a lot in common between the current source and a stale almost copy on the target. This requires rsync access to the filesystems on BOTH sides of the transfer. Copying by ftp and then rsyncing cannot gain much if anything over just ftping.

Switches, control, etc seems much more elaborate and competent, probably because the differences matter much more when stuff is remote and longwinded and subject to somebody pulling the plug mid-copy. I will often use rsync for a local-local copy when something else would actually be faster and maybe better because I know rsync switches which do something I can live with and I sometimes get nasty surprises because I use the wrong switches with the something else. Unlikely, but IF, GIANT SIZED IF, the rsync switches are consonant with playing with ftp (doing similar to wget, but also with an wput counterpart), it would be quite convenient in a lot of cases. Unfortunately, if I had to bet, I'd bet for something lurking that makes it a very bad idea. 
A number of ftp problems show up as rsync errors.
How to interpret those errors. 
I think they lose in the translation.

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