Change/Restore Linux's System Date & Time

change-date-time.bash

# disable NTP sync
sudo timedatectl set-ntp false
# set the date-time
sudo timedatectl set-time "2019-10-29 16:20:00"
# set the timezone
sudo timedatectl set-timezone Europe/London

enable-ntp-to-reset.bash

# select & set the timezone
sudo timedatectl set-timezone `timedatectl list-timezones | grep <city>`
# enable the NTP service to auto-update the datetime
sudo timedatectl set-ntp true
# If using a service like chrony or ntpd to make changes,
# these are not shown by timedatectl until systemd-timesyncd is restarted:
sudo systemctl restart systemd-timesyncd
# check timesyncd's status
sudo systemctl status systemd-timesyncd
# check the timedatectl status
timedatectl