Ubuntu Manpage: timedatectl - Control the system time and date

Provided by: systemd_237-3ubuntu10.57_amd64

NAME

       timedatectl - Control the system time and date

SYNOPSIS


       timedatectl [OPTIONS...] {COMMAND}

DESCRIPTION

       timedatectl may be used to query and change the system clock and its settings.

       Use systemd-firstboot(1) to initialize the system time zone for mounted (but not booted) system images.

OPTIONS

The following options are understood:

--no-ask-password
Do not query the user for authentication for privileged operations.

--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.

-H, --host=
Execute the operation remotely. Specify a hostname, or a username and hostname separated by "@", to
connect to. The hostname may optionally be suffixed by a container name, separated by ":", which
connects directly to a specific container on the specified host. This will use SSH to talk to the
remote machine manager instance. Container names may be enumerated with machinectl -H HOST.

-M, --machine=
Execute operation on a local container. Specify a container name to connect to.

-h, --help
Print a short help text and exit.

--version
Print a short version string and exit.

--no-pager
Do not pipe output into a pager.

The following commands are understood:

status
Show current settings of the system clock and RTC, including whether network time synchronization
through systemd-timesyncd.service is active. Even if it is inactive, a different service might still
synchronize the clock.

set-time [TIME]
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-timezone [TIMEZONE]
Set the system time zone to the specified value. Available timezones 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-timezones
List available time zones, one per line. Entries from the list can be set as the system timezone with
set-timezone.

set-local-rtc [BOOL]
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
timezone is not fully supported and will create various problems with time zone changes and daylight
saving adjustments. If at all possible, keep the RTC in UTC mode. 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).

set-ntp [BOOL]
Takes a boolean argument. Controls whether network time synchronization is active and enabled (if
available). This enables and starts, or disables and stops the systemd-timesyncd.service unit. It
does not affect the state of any other, unrelated network time synchronization services that might be
installed on the system. This command is hence mostly equivalent to: systemctl enable --now
systemd-timesyncd.service and systemctl disable --now systemd-timesyncd.service, but is protected by
a different access policy.

Note that even if time synchronization is turned off with this command, another unrelated system
service might still synchronize the clock with the network. Also note that, strictly speaking,
systemd-timesyncd.service does more than just network time synchronization, as it ensures a monotonic
clock on systems without RTC even if no network is available. See systemd-timesyncd.service(8) for
details about this.

EXIT STATUS

       On success, 0 is returned, a non-zero failure code otherwise.

ENVIRONMENT

       $SYSTEMD_PAGER
           Pager to use when --no-pager is not given; overrides $PAGER. If neither $SYSTEMD_PAGER nor $PAGER are
           set, a set of well-known pager implementations are tried in turn, including less(1) and more(1),
           until one is found. If no pager implementation is discovered no pager is invoked. Setting this
           environment variable to an empty string or the value "cat" is equivalent to passing --no-pager.

       $SYSTEMD_LESS
           Override the options passed to less (by default "FRSXMK").

       $SYSTEMD_LESSCHARSET
           Override the charset passed to less (by default "utf-8", if the invoking terminal is determined to be
           UTF-8 compatible).

EXAMPLES

       Show current settings:

           $ timedatectl
                                 Local time: Thu 2017-09-21 16:08:56 CEST
                             Universal time: Thu 2017-09-21 14:08:56 UTC
                                   RTC time: Thu 2017-09-21 14:08:56
                                  Time zone: Europe/Warsaw (CEST, +0200)
                  System clock synchronized: yes
           systemd-timesyncd.service active: yes
                            RTC in local TZ: no

       Enable network time synchronization:

           $ 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 systemd-timesyncd.service
           ● systemd-timesyncd.service - Network Time Synchronization
              Loaded: loaded (/lib/systemd/system/systemd-timesyncd.service; enabled)
              Active: active (running) since Mo 2015-03-30 14:20:38 CEST; 5s ago
                Docs: man:systemd-timesyncd.service(8)
            Main PID: 595 (systemd-timesyn)
              Status: "Using Time Server 216.239.38.15:123 (time4.google.com)."
              CGroup: /system.slice/systemd-timesyncd.service
                      └─595 /lib/systemd/systemd-timesyncd
           ...