I have searched the forum a bit and see a lot of questions about VPS and related issues, but I am looking for a more general guide on how you maintain Rouncdube on a VPS via SSH?
For instance, I would like to install managesieve on my VPS (it lacks any kind of filters per default) and also considering other possible addons to Roundcube for handling my mail on my VPS.
How do I do?
You should search for how to setup and maintain a mail server. Roundcube is just a webmail client and therefore a small part of the over all solution.
Mailserver is already running.
Its all done and configured on the standard OS configuration of the VPS, which includes a working Roundcube, lacking some interesting options..
Again, handling Roundcube via SSH.
So if you've gotten that far your going to need to start piecing it together from each sub-systems documentation. For example the ManageSieve documentation https://wiki2.dovecot.org/Pigeonhole/ManageSieve
Goodie...
I wrote the server was preconfigured, I didn't jack shit.
Thanks. Its a start.