On 2015-06-17, Bob Proulx <bob@proulx.com> wrote:
For example, to set the time and date to 15:00 on 1st February 2014:
sudo date 020115002014
That worked - it took effect after a reboot.
That's strange; I always thought you had to set the hardware clock
(hwclock) for the modified date and time to survive a reboot.
After a reboot I am sure the boot time hwclock set the time. The
system time set by date evaporates when the system shuts down. System
time is not preserved across reboots. But at boot time the boot time
script /etc/init.d/hwclock.sh sets the time from the hardware clock.
The OP set the time and date with 'date' and said it 'worked' after a
reboot; this puzzled me and puzzles me still. There must be a
misapprehension somewhere.
Best is to install ntp and have it set the time from the network at
boot time.
apt-get install ntp
This was the best option before systemd, but now for some (desktop
stand-alone guys and gals) it seems like systemd-timesyncd might be the
better choice (implements only the client-side, lower overhead,
eliminates the need of installing an extraneous program).
If you don't have a network then of course ntp can't work. For
systems such as the Raspberry Pi that don't have a hardware clock the
time is set to a best guess based upon the most recent timestamp on a
statefile in the file system to keep time moving forward.
https://wiki.archlinux.org/index.php/Systemd-timesyncd