Isso é feito sincronizando com a ferramenta ntpdate
.
man ntpdate
NAME
ntpdate - set the date and time via NTP
ntpdate sets the local date and time by polling the Network Time Proto‐
col (NTP) server(s) given as the server arguments to determine the cor‐
rect time. It must be run as root on the local host (unless the option
-q is used). A number of samples are obtained from each of the servers
specified and a subset of the NTP clock filter and selection algorithms
are applied to select the best of these. Note that the accuracy and
reliability of ntpdate depends on the number of servers, the number of
polls each time it is run and the interval between runs.
ntpdate can be run manually as necessary to set the host clock, or it
can be run from the host startup script to set the clock at boot time.
This is useful in some cases to set the clock initially before starting
the NTP daemon ntpd. It is also possible to run ntpdate from a cron
script. However, it is important to note that ntpdate with contrived
cron scripts is no substitute for the NTP daemon, which uses sophisti‐
cated algorithms to maximize accuracy and reliability while minimizing
resource use. Finally, since ntpdate does not discipline the host clock
frequency as does ntpd, the accuracy using ntpdate is limited.
Você pode fazer isso com
sudo ntpdate TIME-SERVER
As listas TIME-SERVER podem ser encontradas aqui