There is no such thing as "GNOME date/time". There is only one setting, the system clock, which all desktop environments show and adjust. It is also accessible using the
Timezone is the only adjustment that can be per-user, as programs will take it from the
$TZ environment variable; although even then, I remember that GNOME's timezone settings were system-wide – that is, changing
/etc/localtime rather than
(Either way, the timezone is irrelevant to Kerberos which only uses UTC timestamps.)
On Linux, you can use
date --set which accepts many date/time formats:
# date --set="13:04"
The weird traditional syntax, which you might need on BSDs, is
# date 02161304
Normally you give it the local hours, and
date automatically converts them to UTC time before setting the system clock (which always runs in UTC). At least on Linux,
date --utc --set... means that it'll accept UTC time directly.
It is also possible to get the time from a NTP timeserver directly, using either one of these:
# ntpd -g -q
("-g" means "allow large time adjustment")
# ntpdate pool.ntp.org
I don't know if Chrony has an alternative. But either way, it doesn't matter much – since you use Kerberos, I assume all your clients run NTP daemons anyway, and will fix up inaccurate clocks.
Well, okay, I lied. In most computers there's also the battery-powered hardware clock.
If you run
chronyd, it will be updated automatically every few minutes.
If for some reason you don't run a NTP client, you can use
hwclock --systohc to store the current time into the hardware clock.