Comment 25 for bug 1520691

Ok, found why it not works.
The character "/" ist automatically added at the end, so it results in "--log-file=xxx/" wtich wont work.
If some valid parameter is at the end witch likes the "/" added, it works.
In this Demo, i added "--partial-dir=/tmp" witch gets to "--partial-dir=/tmp/" witch i s valid.
The xxx file was created in my home folder.

duplicity 'rsync://127.0.0.1/bug/ --log-file=xxx --partial-dir=/tmp' /home/Downloads/

So, when i use the rsync backend, any parameter witch allows to have a "/" at the end will be executed.