why does this rsync commands copy again the same files?

Thu Nov 22 21:02:37 UTC 2012

2012/11/22, Reindl Harald <h.reindl at thelounge.net>:
>
>
> Am 22.11.2012 21:41, schrieb M. Fioretti:
>> Greetings,
>>
>> I am running Fedora 16 x86_64. When I connect an external USB drive
>> and rsync to it my pictures with this command:
>>
>> rsync -rvt --delete --no-o --no-g /home/z/photo/ /media/Verbatim/photo
>
> this command has a error
> the last aparm is missing a trailing slash

Why would that be an error?

Andras