timedatectl

TIMEDATECTL(1) timedatectl TIMEDATECTL(1)

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, 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
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 in systemd-
timedated.service(8).

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

ENVIRONMENT
$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
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 (/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
...

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

systemd 249 TIMEDATECTL(1)

timedatectl

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