man: document in timedatectl(1) that the NTP state shown reflects whether timesyncd...

[thirdparty/systemd.git] / man / timedatectl.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

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<refentry id="timedatectl" conditional='ENABLE_TIMEDATED'
  xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>timedatectl</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Lennart</firstname>
        <surname>Poettering</surname>
        <email>lennart@poettering.net</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>timedatectl</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>timedatectl</refname>
    <refpurpose>Control the system time and date</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>timedatectl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg></command>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>timedatectl</command> may be used to query and
    change the system clock and its settings.</para>

    <para>Use
    <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    to initialize the system time zone for mounted (but not booted)
    system images.</para>
  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following options are understood:</para>

    <variablelist>
      <varlistentry>
        <term><option>--no-ask-password</option></term>

        <listitem><para>Do not query the user for authentication for
        privileged operations.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--adjust-system-clock</option></term>

        <listitem><para>If <command>set-local-rtc</command> 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.</para></listitem>
      </varlistentry>

      <xi:include href="user-system-options.xml" xpointer="host" />
      <xi:include href="user-system-options.xml" xpointer="machine" />

      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
      <xi:include href="standard-options.xml" xpointer="no-pager" />
    </variablelist>

    <para>The following commands are understood:</para>

    <variablelist>
      <varlistentry>
        <term><command>status</command></term>

        <listitem><para>Show current settings of the system clock and
        RTC, including whether NTP is enabled. Note that the NTP state
        simply reflects whether the
        <filename>systemd-timesyncd.service</filename> unit is enabled.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-time [TIME]</command></term>

        <listitem><para>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".</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-timezone [TIMEZONE]</command></term>

        <listitem><para>Set the system time zone to the specified
        value. Available timezones can be listed with
        <command>list-timezones</command>. If the RTC is configured to
        be in the local time, this will also update the RTC time. This
        call will alter the <filename>/etc/localtime</filename>
        symlink. See
        <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>
        for more information.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>list-timezones</command></term>

        <listitem><para>List available time zones, one per line.
        Entries from the list can be set as the system timezone with
        <command>set-timezone</command>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-local-rtc [BOOL]</command></term>

        <listitem><para>Takes a boolean argument. If
        <literal>0</literal>, the system is configured to maintain the
        RTC in universal time. If <literal>1</literal>, 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
        <option>--adjust-system-clock</option> is passed (see above).
        This command will change the 3rd line of
        <filename>/etc/adjtime</filename>, as documented in
        <citerefentry project='man-pages'><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-ntp [BOOL]</command></term>

        <listitem><para>Takes a boolean argument. Controls whether NTP
        based network time synchronization is enabled (if
        available). This enables or disables the
        <filename>systemd-timesyncd.service</filename>
        unit.</para></listitem>
      </varlistentry>

    </variablelist>

  </refsect1>

  <refsect1>
    <title>Exit status</title>

    <para>On success, 0 is returned, a non-zero failure
    code otherwise.</para>
  </refsect1>

  <xi:include href="less-variables.xml" />

  <refsect1>
    <title>Examples</title>
    <para>Show current settings:
    <programlisting>$ timedatectl
      Local time: Fri, 2012-11-02 09:26:46 CET
  Universal time: Fri, 2012-11-02 08:26:46 UTC
  RTC time: Fri, 2012-11-02 08:26:45
  Timezone: Europe/Warsaw
      UTC offset: +0100
     NTP enabled: no
NTP synchronized: no
 RTC in local TZ: no
      DST active: no
 Last DST change: CEST → CET, DST became inactive
      Sun, 2012-10-28 02:59:59 CEST
      Sun, 2012-10-28 02:00:00 CET
 Next DST change: CET → CEST, DST will become active
      the clock will jump one hour forward
      Sun, 2013-03-31 01:59:59 CET
      Sun, 2013-03-31 03:00:00 CEST</programlisting>
    </para>

    <para>Enable an NTP daemon (chronyd):
    <programlisting>$ 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 ===</programlisting>

    <programlisting>$ systemctl status chronyd.service
chronyd.service - NTP client/server
    Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled)
    Active: active (running) since Fri, 2012-11-02 09:36:25 CET; 5s ago
...</programlisting>
    </para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>date</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-timedated.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>