man/timedatectl.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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   8   Copyright 2012 Lennart Poettering
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  23
  24 <refentry id="timedatectl" conditional='ENABLE_TIMEDATED'>
  25
  26         <refentryinfo>
  27                 <title>timedatectl</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>timedatectl</refentrytitle>
  42                 <manvolnum>1</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>timedatectl</refname>
  47                 <refpurpose>Control the system time and date</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <cmdsynopsis>
  52                         <command>timedatectl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg></command>
  53                 </cmdsynopsis>
  54         </refsynopsisdiv>
  55
  56         <refsect1>
  57                 <title>Description</title>
  58
  59                 <para><command>timedatectl</command> may be used to
  60                 query and change the system clock and its
  61                 settings.</para>
  62         </refsect1>
  63
  64         <refsect1>
  65                 <title>Options</title>
  66
  67                 <para>The following options are understood:</para>
  68
  69                 <variablelist>
  70                         <varlistentry>
  71                                 <term><option>-h</option></term>
  72                                 <term><option>--help</option></term>
  73
  74                                 <listitem><para>Prints a short help
  75                                 text and exits.</para></listitem>
  76                         </varlistentry>
  77
  78                         <varlistentry>
  79                                 <term><option>--version</option></term>
  80
  81                                 <listitem><para>Prints a short version
  82                                 string and exits.</para></listitem>
  83                         </varlistentry>
  84
  85                         <varlistentry>
  86                                 <term><option>--no-pager</option></term>
  87
  88                                 <listitem><para>Do not pipe output into a
  89                                 pager.</para></listitem>
  90                         </varlistentry>
  91
  92                         <varlistentry>
  93                                 <term><option>--no-ask-password</option></term>
  94
  95                                 <listitem><para>Don't query the user
  96                                 for authentication for privileged
  97                                 operations.</para></listitem>
  98                         </varlistentry>
  99
 100                         <varlistentry>
 101                                 <term><option>-H</option></term>
 102                                 <term><option>--host</option></term>
 103
 104                                 <listitem><para>Execute the operation
 105                                 remotely. Specify a hostname, or
 106                                 username and hostname separated by @,
 107                                 to connect to. This will use SSH to
 108                                 talk to a remote
 109                                 system.</para></listitem>
 110                         </varlistentry>
 111
 112                         <varlistentry>
 113                                 <term><option>--adjust-system-clock</option></term>
 114
 115                                 <listitem><para>If
 116                                 <command>set-local-rtc</command> is
 117                                 invoked and this option is passed the
 118                                 system clock is synchronized from the
 119                                 RTC again, taking the new setting into
 120                                 account. Otherwise the RTC is
 121                                 synchronized from the system
 122                                 clock.</para></listitem>
 123                         </varlistentry>
 124                 </variablelist>
 125
 126                 <para>The following commands are understood:</para>
 127
 128                 <variablelist>
 129                         <varlistentry>
 130                                 <term><command>status</command></term>
 131
 132                                 <listitem><para>Show current settings
 133                                 of the system clock and
 134                                 RTC.</para></listitem>
 135                         </varlistentry>
 136
 137                         <varlistentry>
 138                                 <term><command>set-time [TIME]</command></term>
 139
 140                                 <listitem><para>Set the system clock
 141                                 to the specified time. This will also
 142                                 update the RTC time accordingly. The time
 143                                 may be specified in the format
 144                                 "2012-10-30
 145                                 18:17:16".</para></listitem>
 146                         </varlistentry>
 147
 148                         <varlistentry>
 149                                 <term><command>set-timezone [TIMEZONE]</command></term>
 150
 151                                 <listitem><para>Set the system time
 152                                 zone to the specified value. Available
 153                                 time zones can be listed with
 154                                 <command>list-timezones</command>. If
 155                                 the RTC is configured to be in the
 156                                 local time this will also update the
 157                                 RTC time. This call will alter the
 158                                 <filename>/etc/localtime</filename>
 159                                 symlink. See
 160                                 <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 161                                 for more
 162                                 information.</para></listitem>
 163                         </varlistentry>
 164
 165                         <varlistentry>
 166                                 <term><command>list-timezones</command></term>
 167
 168                                 <listitem><para>List available time
 169                                 zones, one per line. Entries from the
 170                                 list can be set as the system
 171                                 time zone with
 172                                 <command>set-timezone</command>.</para></listitem>
 173                         </varlistentry>
 174
 175                         <varlistentry>
 176                                 <term><command>set-local-rtc [BOOL]</command></term>
 177
 178                                 <listitem><para>Takes a boolean
 179                                 argument. If <literal>0</literal> the
 180                                 system is configured to maintain the
 181                                 RTC in universal time, if
 182                                 <literal>1</literal> it will maintain
 183                                 the RTC in local time instead. Note
 184                                 that maintaining the RTC in the local
 185                                 time zone is not fully supported and
 186                                 will create various problems with time
 187                                 zone changes and daylight saving
 188                                 adjustments. If at all possible use
 189                                 RTC in UTC. Note that invoking this
 190                                 will also synchronize the RTC from the
 191                                 system clock, unless
 192                                 <option>--adjust-system-clock</option> is
 193                                 passed (see above). This command will
 194                                 change the 3rd line of
 195                                 <filename>/etc/adjtime</filename>, as
 196                                 documented in
 197                                 <citerefentry><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para></listitem>
 198                         </varlistentry>
 199
 200                         <varlistentry>
 201                                 <term><command>set-ntp [BOOL]</command></term>
 202
 203                                 <listitem><para>Takes a boolean
 204                                 argument. Controls whether NTP based
 205                                 network time synchronization is
 206                                 enabled (if
 207                                 available).</para></listitem>
 208                         </varlistentry>
 209
 210                 </variablelist>
 211
 212         </refsect1>
 213
 214         <refsect1>
 215                 <title>Exit status</title>
 216
 217                 <para>On success 0 is returned, a non-zero failure
 218                 code otherwise.</para>
 219         </refsect1>
 220
 221         <refsect1>
 222                 <title>Environment</title>
 223
 224                 <variablelist class='environment-variables'>
 225                         <varlistentry>
 226                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 227                                 <listitem><para>Pager to use when
 228                                 <option>--no-pager</option> is not given;
 229                                 overrides <varname>$PAGER</varname>.  Setting
 230                                 this to an empty string or the value
 231                                 <literal>cat</literal> is equivalent to passing
 232                                 <option>--no-pager</option>.</para></listitem>
 233                         </varlistentry>
 234                 </variablelist>
 235         </refsect1>
 236
 237         <refsect1>
 238                 <title>Examples</title>
 239                 <para>Show current settings:
 240                 <programlisting>
 241 $ timedatectl
 242       Local time: Fri, 2012-11-02 09:26:46 CET
 243   Universal time: Fri, 2012-11-02 08:26:46 UTC
 244         RTC time: Fri, 2012-11-02 08:26:45
 245         Timezone: Europe/Warsaw
 246       UTC offset: +0100
 247      NTP enabled: no
 248 NTP synchronized: no
 249  RTC in local TZ: no
 250       DST active: no
 251  Last DST change: CEST → CET, DST became inactive
 252                   Sun, 2012-10-28 02:59:59 CEST
 253                   Sun, 2012-10-28 02:00:00 CET
 254  Next DST change: CET → CEST, DST will become active
 255                   the clock will jump one hour forward
 256                   Sun, 2013-03-31 01:59:59 CET
 257                   Sun, 2013-03-31 03:00:00 CEST
 258                 </programlisting>
 259                 </para>
 260
 261                 <para>Enable an NTP daemon (chronyd):
 262                 <programlisting>
 263 $ timedatectl set-ntp true
 264 ==== AUTHENTICATING FOR org.freedesktop.timedate1.set-ntp ===
 265 Authentication is required to control whether network time synchronization shall be enabled.
 266 Authenticating as: user
 267 Password: ********
 268 ==== AUTHENTICATION COMPLETE ===
 269                 </programlisting>
 270
 271                 <programlisting>
 272 $ systemctl status chronyd.service
 273 chronyd.service - NTP client/server
 274           Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled)
 275           Active: active (running) since Fri, 2012-11-02 09:36:25 CET; 5s ago
 276 ...
 277                 </programlisting>
 278                 </para>
 279         </refsect1>
 280
 281         <refsect1>
 282                 <title>See Also</title>
 283                 <para>
 284                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 285                         <citerefentry><refentrytitle>hwclock</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 286                         <citerefentry><refentrytitle>date</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 287                         <citerefentry><refentrytitle>localtime</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 288                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 289                         <citerefentry><refentrytitle>systemd-timedated.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 290                 </para>
 291         </refsect1>
 292
 293 </refentry>