How to 'do-release-upgrade' from 16.04 to 18.04 remotely using PuTTY?

[Dr Rainer Woitok]

Bo,

On Saturday, 2019-04-06 15:28:06 +0200, you wrote:

> ...
> My problem is that I *want* to update my system but at the same time I
> don't want to risk failure since the box acts as a Subversion backup
> server being sent nightly updates via svnsync over the Internet.

Perhaps a stupid question:  How did you initially  install Linux on your
server without a console connected to it?  Can't you do this just anoth-
er time?

Sincerely,
  Rainer