Provided by: systemd_251.4-1ubuntu7_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, 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.
Note: if $SYSTEMD_PAGERSECURE is not set, $SYSTEMD_PAGER (as well as $PAGER) will be
silently ignored.
$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)