# dpkg-reconfigure locales tzdata

If the system clock itself is wrong use

# apt install ntp update-rc.d
# update-rc.d ntp defaults
# /etc/init.d/ntp start && sleep 10
# hwclock --systohc

EDIT: the above code block presumes that Windows is not also installed. If Windows is installed than make that use a sensible time standard:

https://wiki.archlinux.org/title/System … ft_Windows

Ubuntu and various random crappy interweb sites seem to recommend disabling UTC in GNU/Linux systems but that's stupid advice. Make Windows use UTC instead.

consequence; the time is wrong as the time zone is also wrong. and the formats for the visualization of time etc. also (I need those used in the European Union, for ex. in English speaking countries but not GB).

the other things (especially language, country) stay better like the are now (also wrong, to limit the changes...).

is a

simple way for ex. using dpkg

known to make the 3 changes marked in fat above?