On Tue, 30 Mar 2021 19:13:00 +0200, Dario wrote in message
<20210330171300.GA3904@???>:

> Il 30/03/2021 alle 18:59, Adam Borowski ha scritto:
>
> >I bet your locale is set to en_US.
>
> Indeed it is!
>
> [...]
> >So in Buster (and thus Beowulf and Chimaera), meaning of "en_US"
> >changed to include that silly 12-hour time.
>
> Surely they couldn't avoid fixing what wasn't broken. Thank you for
> steering me in the right direction: I found that setting LC_TIME=C
> is enough to get my 24 hours back.

..oneliner quickie fix:
Paste the below into all xterms you want fixed:
date &&LC_TIME=C.UTF-8 &&export LC_TIME &&date

..longer term fix: locale >>/etc/default/locale
then edit /etc/default/locale to your liking,
then maybe do an export loop like:
for i in $(cat /etc/default/locale ) ;do echo $i \
&& export $(echo $i |cut -d"=" -f1 ) &&grep $i \
/etc/default/locale &&export |grep $i ;done

--
..med vennlig hilsen = with Kind Regards from Arnt Karlsen
...with a number of polar bear hunters in his ancestry...
Scenarios always come in sets of three:
best case, worst case, and just in case.