timedatectl — Control the system time and date
timedatectl [OPTIONS...]  {COMMAND} 
The following options are understood:
-h, --help¶Prints a short help text and exits.
--version¶Prints a short version string and exits.
--no-pager¶Do not pipe output into a pager.
--no-ask-password¶Don't query the user for authentication for privileged operations.
-H, --host¶Execute the operation remotely. Specify a hostname, or username and hostname separated by @, to connect to. This will use SSH to talk to a remote system.
--adjust-system-clock¶If set-local-rtc is invoked and this option is passed the system clock is synchronized from the RTC again, taking the new setting into account. Otherwise the RTC is synchronized from the system clock.
The following commands are understood:
Show current settings of the system clock and RTC.
Set the system clock to the specified time. This will also update the RTC time accordingly. The time may be specified in the format "2012-10-30 18:17:16".
Set the system time
                                zone to the specified value. Available
                                time zones can be listed with
                                list-timezones. If
                                the RTC is configured to be in the
                                local time this will also update the
                                RTC time. This call will alter the
                                /etc/localtime
                                symlink. See
                                localtime(5)
                                for more
                                information.
List available time zones, one per line. Entries from the list can be set as the system time zone with set-timezone.
Takes a boolean
                                argument. If 0 the
                                system is configured to maintain the
                                RTC in universal time, if
                                1 it will maintain
                                the RTC in local time instead. Note
                                that maintaining the RTC in the local
                                time zone is not fully supported and
                                will create various problems with time
                                zone changes and daylight saving
                                adjustments. If at all possible use
                                RTC in UTC. Note that invoking this
                                will also synchronize the RTC from the
                                system clock, unless
                                --adjust-system-clock is
                                passed (see above). This command will
                                change the 3rd line of
                                /etc/adjtime, as
                                documented in
                                hwclock(8).
Takes a boolean argument. Controls whether NTP based network time synchronization is enabled (if available).
$SYSTEMD_PAGER¶Pager to use when
                                --no-pager is not given;
                                overrides $PAGER.  Setting
                                this to an empty string or the value
                                cat is equivalent to passing
                                --no-pager.
Show current settings:
$ timedatectl
      Local time: Fri, 2012-11-02 09:26:46 CET
  Universal time: Fri, 2012-11-02 08:26:46 UTC
        RTC time: Fri, 2012-11-02 08:26:45
        Timezone: Europe/Warsaw
      UTC offset: +0100
     NTP enabled: no
NTP synchronized: no
 RTC in local TZ: no
      DST active: no
 Last DST change: CEST → CET, DST became inactive
                  Sun, 2012-10-28 02:59:59 CEST
                  Sun, 2012-10-28 02:00:00 CET
 Next DST change: CET → CEST, DST will become active
                  the clock will jump one hour forward
                  Sun, 2013-03-31 01:59:59 CET
                  Sun, 2013-03-31 03:00:00 CEST
                
Enable an NTP daemon (chronyd):
$ timedatectl set-ntp true
==== AUTHENTICATING FOR org.freedesktop.timedate1.set-ntp ===
Authentication is required to control whether network time synchronization shall be enabled.
Authenticating as: user
Password: ********
==== AUTHENTICATION COMPLETE ===
                
$ systemctl status chronyd.service
chronyd.service - NTP client/server
          Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled)
          Active: active (running) since Fri, 2012-11-02 09:36:25 CET; 5s ago
...