The typical way to set the timezone is to use timedatectl, e.g.:
sudo timedatectl set-timezone America/New_York
So I can use a named zone, or UTC.
But how do I set the zone without a name - e.g. UTC-5 or UTC+10 or whatever?
Yes, quite inconvenient indeed.
This is kind of lame to suggest but you could list all available timezone names with timedatectl list-timezones and look for a region or city name that you know is located in the UTC timezone you are interested in. Sorry, I know that is not the answer you were looking for .....
timedatectland I need to fall back to one of those older TZ tools? – lonix Sep 02 '19 at 18:51