timedatectl(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | COMMANDS | OPTIONS | EXIT STATUS | ENVIRONMENT | EXAMPLES | SEE ALSO | COLOPHON

TIMEDATECTL(1)                 timedatectl                TIMEDATECTL(1)

NAME         top

       timedatectl - Control the system time and date

SYNOPSIS         top

       timedatectl [OPTIONS...] {COMMAND}

DESCRIPTION         top

       timedatectl may be used to query and change the system clock and
       its settings, and enable or disable time synchronization
       services.

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

       timedatectl may be used to show the current status of time
       synchronization services, for example
       systemd-timesyncd.service(8).

COMMANDS         top

       The following commands are understood:

       status
           Show current settings of the system clock and RTC, including
           whether network time synchronization is active. If no command
           is specified, this is the implied default.

       show
           Show the same information as status, but in machine readable
           form. This command is intended to be used whenever
           computer-parsable output is required. Use status if you are
           looking for formatted human-readable output.

           By default, empty properties are suppressed. Use --all to
           show those too. To select specific properties to show, use
           --property=.

       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). If the
           argument is true, this enables and starts the first existing
           network synchronization service. If the argument is false,
           then this disables and stops the known network
           synchronization services. The way that the list of services
           is built is described below.

   systemd-timesyncd Commands
       The following commands are specific to
       systemd-timesyncd.service(8).

       timesync-status
           Show current status of systemd-timesyncd.service(8). If
           --monitor is specified, then this will monitor the status
           updates.

       show-timesync
           Show the same information as timesync-status, but in machine
           readable form. This command is intended to be used whenever
           computer-parsable output is required. Use timesync-status if
           you are looking for formatted human-readable output.

           By default, empty properties are suppressed. Use --all to
           show those too. To select specific properties to show, use
           --property=.

       ntp-servers INTERFACE SERVER...
           Set the interface specific NTP servers. This command can be
           used only when the interface is managed by systemd-networkd.

       revert INTERFACE
           Revert the interface specific NTP servers. This command can
           be used only when the interface is managed by
           systemd-networkd.

OPTIONS         top

       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.

       --monitor
           If timesync-status is invoked and this option is passed, then
           timedatectl monitors the status of
           systemd-timesyncd.service(8) and updates the outputs. Use
           Ctrl+C to terminate the monitoring.

       -a, --all
           When showing properties of systemd-timesyncd.service(8), show
           all properties regardless of whether they are set or not.

       -p, --property=
           When showing properties of systemd-timesyncd.service(8),
           limit display to certain properties as specified as argument.
           If not specified, all set properties are shown. The argument
           should be a property name, such as "ServerName". If specified
           more than once, all properties with the specified names are
           shown.

       --value
           When printing properties with show-timesync, only print the
           value, and skip the property name and "=".

       -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 port ssh is
           listening on, separated by ":", and then 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. Put IPv6 addresses in
           brackets.

       -M, --machine=
           Execute operation on a local container. Specify a container
           name to connect to, optionally prefixed by a user name to
           connect as and a separating "@" character. If the special
           string ".host" is used in place of the container name, a
           connection to the local system is made (which is useful to
           connect to a specific user's user bus: "--user
           --machine=lennart@.host"). If the "@" syntax is not used, the
           connection is made as root user. If the "@" syntax is used
           either the left hand side or the right hand side may be
           omitted (but not both) in which case the local user name and
           ".host" are implied.

       -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.

EXIT STATUS         top

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

ENVIRONMENT         top

       $SYSTEMD_LOG_LEVEL
           The maximum log level of emitted messages (messages with a
           higher log level, i.e. less important ones, will be
           suppressed). Either one of (in order of decreasing
           importance) emerg, alert, crit, err, warning, notice, info,
           debug, or an integer in the range 0...7. See syslog(3) for
           more information.

       $SYSTEMD_LOG_COLOR
           A boolean. If true, messages written to the tty will be
           colored according to priority.

           This setting is only useful when messages are written
           directly to the terminal, because journalctl(1) and other
           tools that display logs will color messages based on the log
           level on their own.

       $SYSTEMD_LOG_TIME
           A boolean. If true, console log messages will be prefixed
           with a timestamp.

           This setting is only useful when messages are written
           directly to the terminal or a file, because journalctl(1) and
           other tools that display logs will attach timestamps based on
           the entry metadata on their own.

       $SYSTEMD_LOG_LOCATION
           A boolean. If true, messages will be prefixed with a filename
           and line number in the source code where the message
           originates.

           Note that the log location is often attached as metadata to
           journal entries anyway. Including it directly in the message
           text can nevertheless be convenient when debugging programs.

       $SYSTEMD_LOG_TID
           A boolean. If true, messages will be prefixed with the
           current numerical thread ID (TID).

           Note that the this information is attached as metadata to
           journal entries anyway. Including it directly in the message
           text can nevertheless be convenient when debugging programs.

       $SYSTEMD_LOG_TARGET
           The destination for log messages. One of console (log to the
           attached tty), console-prefixed (log to the attached tty but
           with prefixes encoding the log level and "facility", see
           syslog(3), kmsg (log to the kernel circular log buffer),
           journal (log to the journal), journal-or-kmsg (log to the
           journal if available, and to kmsg otherwise), auto (determine
           the appropriate log target automatically, the default), null
           (disable log output).

       $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").

           Users might want to change two options in particular:

           K
               This option instructs the pager to exit immediately when
               Ctrl+C is pressed. To allow less to handle Ctrl+C itself
               to switch back to the pager command prompt, unset this
               option.

               If the value of $SYSTEMD_LESS does not include "K", and
               the pager that is invoked is less, Ctrl+C will be ignored
               by the executable, and needs to be handled by the pager.

           X
               This option instructs the pager to not send termcap
               initialization and deinitialization strings to the
               terminal. It is set by default to allow command output to
               remain visible in the terminal even after the pager
               exits. Nevertheless, this prevents some pager
               functionality from working, in particular paged output
               cannot be scrolled with the mouse.

           See less(1) for more discussion.

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

       $SYSTEMD_PAGERSECURE
           Takes a boolean argument. When true, the "secure" mode of the
           pager is enabled; if false, disabled. If $SYSTEMD_PAGERSECURE
           is not set at all, secure mode is enabled if the effective
           UID is not the same as the owner of the login session, see
           geteuid(2) and sd_pid_get_owner_uid(3). In secure mode,
           LESSSECURE=1 will be set when invoking the pager, and the
           pager shall disable commands that open or create new files or
           start new subprocesses. When $SYSTEMD_PAGERSECURE is not set
           at all, pagers which are not known to implement secure mode
           will not be used. (Currently only less(1) implements secure
           mode.)

           Note: when commands are invoked with elevated privileges, for
           example under sudo(8) or pkexec(1), care must be taken to
           ensure that unintended interactive features are not enabled.
           "Secure" mode for the pager may be enabled automatically as
           describe above. Setting SYSTEMD_PAGERSECURE=0 or not removing
           it from the inherited environment allows the user to invoke
           arbitrary commands. Note that if the $SYSTEMD_PAGER or $PAGER
           variables are to be honoured, $SYSTEMD_PAGERSECURE must be
           set too. It might be reasonable to completely disable the
           pager using --no-pager instead.

       $SYSTEMD_COLORS
           Takes a boolean argument. When true, systemd and related
           utilities will use colors in their output, otherwise the
           output will be monochrome. Additionally, the variable can
           take one of the following special values: "16", "256" to
           restrict the use of colors to the base 16 or 256 ANSI colors,
           respectively. This can be specified to override the automatic
           decision based on $TERM and what the console is connected to.

       $SYSTEMD_URLIFY
           The value must be a boolean. Controls whether clickable links
           should be generated in the output for terminal emulators
           supporting this. This can be specified to override the
           decision that systemd makes based on $TERM and other
           conditions.

EXAMPLES         top

       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
                         NTP service: active
                     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 (/usr/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 /usr/lib/systemd/systemd-timesyncd
           ...

       Show current status of systemd-timesyncd.service(8):

           $ timedatectl timesync-status
                  Server: 216.239.38.15 (time4.google.com)
           Poll interval: 1min 4s (min: 32s; max 34min 8s)
                    Leap: normal
                 Version: 4
                 Stratum: 1
               Reference: GPS
               Precision: 1us (-20)
           Root distance: 335us (max: 5s)
                  Offset: +316us
                   Delay: 349us
                  Jitter: 0
            Packet count: 1
               Frequency: -8.802ppm

SEE ALSO         top

       systemd(1), hwclock(8), date(1), localtime(5), systemctl(1),
       systemd-timedated.service(8), systemd-timesyncd.service(8),
       systemd-firstboot(1)

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2021-08-27.  (At that
       time, the date of the most recent commit that was found in the
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       problems in this HTML version of the page, or you believe there
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       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 249                                               TIMEDATECTL(1)

Pages that refer to this page: systemd-firstboot(1)localtime(5)systemd.time(7)systemd-machined.service(8)systemd-timedated.service(8)systemd-timesyncd.service(8)