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 (/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