man/systemd.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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   5 <!--
   6   This file is part of systemd.
   7
   8   Copyright 2010 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 -->
  23
  24 <refentry id="systemd">
  25
  26         <refentryinfo>
  27                 <title>systemd</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>systemd</refentrytitle>
  42                 <manvolnum>1</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd</refname>
  47                 <refname>init</refname>
  48                 <refpurpose>systemd system and service manager</refpurpose>
  49         </refnamediv>
  50
  51         <refsynopsisdiv>
  52                 <cmdsynopsis>
  53                         <command>systemd <arg choice="opt" rep="repeat">OPTIONS</arg></command>
  54                 </cmdsynopsis>
  55                 <cmdsynopsis>
  56                         <command>init <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg></command>
  57                 </cmdsynopsis>
  58         </refsynopsisdiv>
  59
  60         <refsect1>
  61                 <title>Description</title>
  62
  63                 <para>systemd is a system and service manager for
  64                 Linux operating systems. When run as first process on
  65                 boot (as PID 1), it acts as init system that brings
  66                 up and maintains userspace services.</para>
  67
  68                 <para>For compatibility with SysV, if systemd is called
  69                 as <command>init</command> and a PID that is not
  70                 1, it will execute <command>telinit</command> and pass
  71                 all command line arguments unmodified. That means
  72                 <command>init</command> and <command>telinit</command>
  73                 are mostly equivalent when invoked from normal login sessions. See
  74                 <citerefentry><refentrytitle>telinit</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  75                 for more information.</para>
  76
  77                 <para>When run as system instance, systemd interprets
  78                 the configuration file
  79                 <filename>system.conf</filename>, otherwise
  80                 <filename>user.conf</filename>. See
  81                 <citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  82                 for more information.</para>
  83         </refsect1>
  84
  85         <refsect1>
  86                 <title>Options</title>
  87
  88                 <para>The following options are understood:</para>
  89
  90                 <variablelist>
  91                         <varlistentry>
  92                                 <term><option>-h</option></term>
  93                                 <term><option>--help</option></term>
  94
  95                                 <listitem><para>Prints a short help
  96                                 text and exits.</para></listitem>
  97                         </varlistentry>
  98                         <varlistentry>
  99                                 <term><option>--version</option></term>
 100
 101                                 <listitem><para>Prints a systemd version
 102                                 identifier and exits.</para></listitem>
 103                         </varlistentry>
 104                         <varlistentry>
 105                                 <term><option>--test</option></term>
 106
 107                                 <listitem><para>Determine startup
 108                                 sequence, dump it and exit. This is an
 109                                 option useful for debugging
 110                                 only.</para></listitem>
 111                         </varlistentry>
 112                         <varlistentry>
 113                                 <term><option>--dump-configuration-items</option></term>
 114
 115                                 <listitem><para>Dump understood unit
 116                                 configuration items. This outputs a
 117                                 terse but complete list of
 118                                 configuration items understood in unit
 119                                 definition files.</para></listitem>
 120                         </varlistentry>
 121                         <varlistentry>
 122                                 <term><option>--introspect=</option></term>
 123
 124                                 <listitem><para>Extract D-Bus
 125                                 interface introspection data. This is
 126                                 mostly useful at install time
 127                                 to generate data suitable for the
 128                                 D-Bus interfaces
 129                                 repository. Optionally the interface
 130                                 name for the introspection data may be
 131                                 specified. If omitted, the
 132                                 introspection data for all interfaces
 133                                 is dumped.</para></listitem>
 134                         </varlistentry>
 135                         <varlistentry>
 136                                 <term><option>--unit=</option></term>
 137
 138                                 <listitem><para>Set default unit to
 139                                 activate on startup. If not specified
 140                                 defaults to
 141                                 <filename>default.target</filename>.</para></listitem>
 142                         </varlistentry>
 143                         <varlistentry>
 144                                 <term><option>--system</option></term>
 145                                 <term><option>--user</option></term>
 146
 147                                 <listitem><para>Tell systemd to run a
 148                                 system instance (resp. user
 149                                 instance), even if the process ID is
 150                                 not 1 (resp. is 1), i.e. systemd is
 151                                 not (resp. is) run as init process.
 152                                 Normally it should not be necessary to
 153                                 pass these options, as systemd
 154                                 automatically detects the mode it is
 155                                 started in. These options are hence of
 156                                 little use except for debugging. Note
 157                                 that it is not supported booting and
 158                                 maintaining a full system with systemd
 159                                 running in <option>--system</option>
 160                                 mode, but PID not 1. In practice,
 161                                 passing <option>--system</option> explicitly is
 162                                 only useful in conjunction with
 163                                 <option>--test</option>.</para></listitem>
 164                         </varlistentry>
 165                         <varlistentry>
 166                                 <term><option>--dump-core</option></term>
 167
 168                                 <listitem><para>Dump core on
 169                                 crash. This switch has no effect when
 170                                 run as user
 171                                 instance.</para></listitem>
 172                         </varlistentry>
 173                         <varlistentry>
 174                                 <term><option>--crash-shell</option></term>
 175
 176                                 <listitem><para>Run shell on
 177                                 crash. This switch has no effect when
 178                                 run as user
 179                                 instance.</para></listitem>
 180                         </varlistentry>
 181                         <varlistentry>
 182                                 <term><option>--confirm-spawn</option></term>
 183
 184                                 <listitem><para>Ask for confirmation
 185                                 when spawning processes. This switch
 186                                 has no effect when run as user
 187                                 instance.</para></listitem>
 188                         </varlistentry>
 189                         <varlistentry>
 190                                 <term><option>--show-status=</option></term>
 191
 192                                 <listitem><para>Show terse service
 193                                 status information while booting. This
 194                                 switch has no effect when run as user
 195                                 instance. Takes a boolean argument
 196                                 which may be omitted which is
 197                                 interpreted as
 198                                 <option>true</option>.</para></listitem>
 199                         </varlistentry>
 200                         <varlistentry>
 201                                 <term><option>--log-target=</option></term>
 202
 203                                 <listitem><para>Set log
 204                                 target. Argument must be one of
 205                                 <option>console</option>,
 206                                 <option>journal</option>,
 207                                 <option>syslog</option>,
 208                                 <option>kmsg</option>,
 209                                 <option>journal-or-kmsg</option>,
 210                                 <option>syslog-or-kmsg</option>,
 211                                 <option>null</option>.</para></listitem>
 212                         </varlistentry>
 213                         <varlistentry>
 214                                 <term><option>--log-level=</option></term>
 215
 216                                 <listitem><para>Set log level. As
 217                                 argument this accepts a numerical log
 218                                 level or the well-known <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 219                                 symbolic names (lowercase):
 220                                 <option>emerg</option>,
 221                                 <option>alert</option>,
 222                                 <option>crit</option>,
 223                                 <option>err</option>,
 224                                 <option>warning</option>,
 225                                 <option>notice</option>,
 226                                 <option>info</option>,
 227                                 <option>debug</option>.</para></listitem>
 228                         </varlistentry>
 229                         <varlistentry>
 230                                 <term><option>--log-color=</option></term>
 231
 232                                 <listitem><para>Highlight important
 233                                 log messages. Argument is a boolean
 234                                 value. If the argument is omitted it
 235                                 defaults to
 236                                 <option>true</option>.</para></listitem>
 237                         </varlistentry>
 238                         <varlistentry>
 239                                 <term><option>--log-location=</option></term>
 240
 241                                 <listitem><para>Include code location
 242                                 in log messages. This is mostly
 243                                 relevant for debugging
 244                                 purposes. Argument is a boolean
 245                                 value. If the argument is omitted
 246                                 it defaults to
 247                                 <option>true</option>.</para></listitem>
 248                         </varlistentry>
 249                         <varlistentry>
 250                                 <term><option>--default-standard-output=</option></term>
 251                                 <term><option>--default-standard-error=</option></term>
 252
 253                                 <listitem><para>Sets the default
 254                                 output resp. error output for all
 255                                 services and sockets, i.e. controls
 256                                 the default for
 257                                 <option>StandardOutput=</option>
 258                                 resp. <option>StandardError=</option>
 259                                 (see
 260                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 261                                 for details). Takes one of
 262                                 <option>inherit</option>,
 263                                 <option>null</option>,
 264                                 <option>tty</option>,
 265                                 <option>journal</option>,
 266                                 <option>journal+console</option>,
 267                                 <option>syslog</option>,
 268                                 <option>syslog+console</option>,
 269                                 <option>kmsg</option>,
 270                                 <option>kmsg+console</option>.  If the
 271                                 argument is omitted
 272                                 <option>--default-standard-output=</option>
 273                                 defaults to <option>journal</option>
 274                                 and
 275                                 <option>--default-standard-error=</option>
 276                                 to
 277                                 <option>inherit</option>.</para></listitem>
 278                         </varlistentry>
 279                 </variablelist>
 280         </refsect1>
 281
 282         <refsect1>
 283                 <title>Concepts</title>
 284
 285                 <para>systemd provides a dependency system between
 286                 various entities called "units". Units encapsulate
 287                 various objects that are relevant for system boot-up
 288                 and maintenance. The majority of units are configured
 289                 in unit configuration files, whose syntax and basic
 290                 set of options is described in
 291                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 292                 however some are created automatically from other
 293                 configuration or dynamically from system state. Units
 294                 may be 'active' (meaning started, bound, plugged in,
 295                 ...  depending on the unit type, see below), or
 296                 'inactive' (meaning stopped, unbound, unplugged, ...),
 297                 as well as in the process of being activated or
 298                 deactivated, i.e. between the two states (these states
 299                 are called 'activating', 'deactivating'). A special
 300                 'failed' state is available as well which is very
 301                 similar to 'inactive' and is entered when the service
 302                 failed in some way (process returned error code on
 303                 exit, or crashed, or an operation timed out). If this
 304                 state is entered the cause will be logged, for later
 305                 reference. Note that the various unit types may have a
 306                 number of additional substates, which are mapped to
 307                 the five generalized unit states described
 308                 here.</para>
 309
 310                 <para>The following unit types are available:</para>
 311
 312                 <orderedlist>
 313                         <listitem><para>Service units, which control
 314                         daemons and the processes they consist of. For
 315                         details see
 316                         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 317
 318                         <listitem><para>Socket units, which
 319                         encapsulate local IPC or network sockets in
 320                         the system, useful for socket-based
 321                         activation. For details about socket units see
 322                         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 323                         for details on socket-based activation and
 324                         other forms of activation, see
 325                         <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem>
 326
 327                         <listitem><para>Target units are useful to
 328                         group units, or provide well-known
 329                         synchronization points during boot-up, see
 330                         <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 331
 332                         <listitem><para>Device units expose kernel
 333                         devices in systemd and may be used to
 334                         implement device-based activation. For details
 335                         see
 336                         <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 337
 338                         <listitem><para>Mount units control mount
 339                         points in the file system, for details see
 340                         <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 341
 342                         <listitem><para>Automount units provide
 343                         automount capabilities, for on-demand mounting
 344                         of file systems as well as parallelized
 345                         boot-up. See
 346                         <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 347
 348                         <listitem><para>Snapshot units can be used to
 349                         temporarily save the state of the set of
 350                         systemd units, which later may be restored by
 351                         activating the saved snapshot unit. For more
 352                         information see
 353                         <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 354
 355                         <listitem><para>Timer units are useful for
 356                         triggering activation of other units based on
 357                         timers. You may find details in
 358                         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 359
 360                         <listitem><para>Swap units are very similar to
 361                         mount units and encapsulate memory swap
 362                         partitions or files of the operating
 363                         system. They are described in <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 364
 365                         <listitem><para>Path units may be used
 366                         to activate other services when file system
 367                         objects change or are modified. See
 368                         <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 369
 370                 </orderedlist>
 371
 372                 <para>Units are named as their configuration
 373                 files. Some units have special semantics. A detailed
 374                 list is available in
 375                 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
 376
 377                 <para>systemd knows various kinds of dependencies,
 378                 including positive and negative requirement
 379                 dependencies (i.e. <varname>Requires=</varname> and
 380                 <varname>Conflicts=</varname>) as well as ordering
 381                 dependencies (<varname>After=</varname> and
 382                 <varname>Before=</varname>). NB: ordering and
 383                 requirement dependencies are orthogonal. If only a
 384                 requirement dependency exists between two units
 385                 (e.g. <filename>foo.service</filename> requires
 386                 <filename>bar.service</filename>), but no ordering
 387                 dependency (e.g. <filename>foo.service</filename>
 388                 after <filename>bar.service</filename>) and both are
 389                 requested to start, they will be started in
 390                 parallel. It is a common pattern that both requirement
 391                 and ordering dependencies are placed between two
 392                 units. Also note that the majority of dependencies are
 393                 implicitly created and maintained by systemd. In most
 394                 cases it should be unnecessary to declare additional
 395                 dependencies manually, however it is possible to do
 396                 this.</para>
 397
 398                 <para>Application programs and units (via
 399                 dependencies) may request state changes of units. In
 400                 systemd, these requests are encapsulated as 'jobs' and
 401                 maintained in a job queue. Jobs may succeed or can
 402                 fail, their execution is ordered based on the ordering
 403                 dependencies of the units they have been scheduled
 404                 for.</para>
 405
 406                 <para>On boot systemd activates the target unit
 407                 <filename>default.target</filename> whose job is to
 408                 activate on-boot services and other on-boot units by
 409                 pulling them in via dependencies. Usually the unit
 410                 name is just an alias (symlink) for either
 411                 <filename>graphical.target</filename> (for
 412                 fully-featured boots into the UI) or
 413                 <filename>multi-user.target</filename> (for limited
 414                 console-only boots for use in embedded or server
 415                 environments, or similar; a subset of
 416                 graphical.target). However it is at the discretion of
 417                 the administrator to configure it as an alias to any
 418                 other target unit. See
 419                 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 420                 for details about these target units.</para>
 421
 422                 <para>Processes systemd spawns are placed in
 423                 individual Linux control groups named after the unit
 424                 which they belong to in the private systemd
 425                 hierarchy. (see <ulink
 426                 url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>
 427                 for more information about control groups, or short
 428                 "cgroups"). systemd uses this to effectively keep
 429                 track of processes. Control group information is
 430                 maintained in the kernel, and is accessible via the
 431                 file system hierarchy (beneath
 432                 <filename>/sys/fs/cgroup/systemd/</filename>), or in tools
 433                 such as
 434                 <citerefentry><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 435                 (<command>ps xawf -eo pid,user,cgroup,args</command>
 436                 is particularly useful to list all processes and the
 437                 systemd units they belong to.).</para>
 438
 439                 <para>systemd is compatible with the SysV init system
 440                 to a large degree: SysV init scripts are supported and
 441                 simply read as an alternative (though limited)
 442                 configuration file format. The SysV
 443                 <filename>/dev/initctl</filename> interface is
 444                 provided, and compatibility implementations of the
 445                 various SysV client tools are available. In addition to
 446                 that, various established Unix functionality such as
 447                 <filename>/etc/fstab</filename> or the
 448                 <filename>utmp</filename> database are
 449                 supported.</para>
 450
 451                 <para>systemd has a minimal transaction system: if a
 452                 unit is requested to start up or shut down it will add
 453                 it and all its dependencies to a temporary
 454                 transaction. Then, it will verify if the transaction
 455                 is consistent (i.e. whether the ordering of all units
 456                 is cycle-free). If it is not, systemd will try to fix
 457                 it up, and removes non-essential jobs from the
 458                 transaction that might remove the loop. Also, systemd
 459                 tries to suppress non-essential jobs in the
 460                 transaction that would stop a running service. Finally
 461                 it is checked whether the jobs of the transaction
 462                 contradict jobs that have already been queued, and
 463                 optionally the transaction is aborted then. If all
 464                 worked out and the transaction is consistent and
 465                 minimized in its impact it is merged with all already
 466                 outstanding jobs and added to the run
 467                 queue. Effectively this means that before executing a
 468                 requested operation, systemd will verify that it makes
 469                 sense, fixing it if possible, and only failing if it
 470                 really cannot work.</para>
 471
 472                 <para>Systemd contains native implementations of
 473                 various tasks that need to be executed as part of the
 474                 boot process. For example, it sets the host name or
 475                 configures the loopback network device. It also sets
 476                 up and mounts various API file systems, such as
 477                 <filename>/sys</filename> or
 478                 <filename>/proc</filename>.</para>
 479
 480                 <para>For more information about the concepts and
 481                 ideas behind systemd please refer to the <ulink
 482                 url="http://0pointer.de/blog/projects/systemd.html">Original
 483                 Design Document</ulink>.</para>
 484
 485                 <para>Note that some but not all interfaces provided
 486                 by systemd are covered by the <ulink
 487                 url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
 488                 Stability Promise</ulink>.</para>
 489
 490                 <para>Units may be generated dynamically at boot and
 491                 system manager reload time, for example based on other
 492                 configuration files or parameters passed on the kernel
 493                 command line. For details see the <ulink
 494                 url="http://www.freedesktop.org/wiki/Software/systemd/Generators">Generators
 495                 Specification</ulink>.</para>
 496
 497                 <para>Systems which invoke systemd in a container
 498                 resp. initrd environment should implement the
 499                 <ulink
 500                 url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container
 501                 Interface</ulink> resp. <ulink
 502                 url="http://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd
 503                 Interface</ulink> specifications.</para>
 504         </refsect1>
 505
 506         <refsect1>
 507                 <title>Directories</title>
 508
 509                 <variablelist>
 510                         <varlistentry>
 511                                 <term>System unit directories</term>
 512
 513                                 <listitem><para>The systemd system
 514                                 manager reads unit configuration from
 515                                 various directories. Packages that
 516                                 want to install unit files shall place
 517                                 them in the directory returned by
 518                                 <command>pkg-config systemd
 519                                 --variable=systemdsystemunitdir</command>. Other
 520                                 directories checked are
 521                                 <filename>/usr/local/lib/systemd/system</filename>
 522                                 and
 523                                 <filename>/usr/lib/systemd/system</filename>. User
 524                                 configuration always takes
 525                                 precedence. <command>pkg-config
 526                                 systemd
 527                                 --variable=systemdsystemconfdir</command>
 528                                 returns the path of the system
 529                                 configuration directory. Packages
 530                                 should alter the content of these
 531                                 directories only with the
 532                                 <command>enable</command> and
 533                                 <command>disable</command> commands of
 534                                 the
 535                                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 536                                 tool.</para></listitem>
 537                         </varlistentry>
 538                 </variablelist>
 539
 540                 <variablelist>
 541                         <varlistentry>
 542                                 <term>User unit directories</term>
 543
 544                                 <listitem><para>Similar rules apply
 545                                 for the user unit
 546                                 directories. However, here the <ulink
 547                                 url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
 548                                 Base Directory specification</ulink>
 549                                 is followed to find
 550                                 units. Applications should place their
 551                                 unit files in the directory returned
 552                                 by <command>pkg-config systemd
 553                                 --variable=systemduserunitdir</command>. Global
 554                                 configuration is done in the directory
 555                                 reported by <command>pkg-config
 556                                 systemd
 557                                 --variable=systemduserconfdir</command>. The
 558                                 <command>enable</command> and
 559                                 <command>disable</command> commands of
 560                                 the
 561                                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 562                                 tool can handle both global (i.e. for
 563                                 all users) and private (for one user)
 564                                 enabling/disabling of
 565                                 units.</para></listitem>
 566                         </varlistentry>
 567                 </variablelist>
 568
 569                 <variablelist>
 570                         <varlistentry>
 571                                 <term>SysV init scripts directory</term>
 572
 573                                 <listitem><para>The location of the
 574                                 SysV init script directory varies
 575                                 between distributions. If systemd
 576                                 cannot find a native unit file for a
 577                                 requested service, it will look for a
 578                                 SysV init script of the same name
 579                                 (with the
 580                                 <filename>.service</filename> suffix
 581                                 removed).</para></listitem>
 582                         </varlistentry>
 583                 </variablelist>
 584
 585                 <variablelist>
 586                         <varlistentry>
 587                                 <term>SysV runlevel link farm directory</term>
 588
 589                                 <listitem><para>The location of the
 590                                 SysV runlevel link farm directory
 591                                 varies between distributions. systemd
 592                                 will take the link farm into account
 593                                 when figuring out whether a service
 594                                 shall be enabled. Note that a service
 595                                 unit with a native unit configuration
 596                                 file cannot be started by activating it
 597                                 in the SysV runlevel link
 598                                 farm.</para></listitem>
 599                         </varlistentry>
 600                 </variablelist>
 601         </refsect1>
 602
 603         <refsect1>
 604                 <title>Signals</title>
 605
 606                 <variablelist>
 607                         <varlistentry>
 608                                 <term>SIGTERM</term>
 609
 610                                 <listitem><para>Upon receiving this
 611                                 signal the systemd system manager
 612                                 serializes its state, reexecutes
 613                                 itself and deserializes the saved
 614                                 state again. This is mostly equivalent
 615                                 to <command>systemctl
 616                                 daemon-reexec</command>.</para>
 617
 618                                 <para>systemd user managers will
 619                                 start the
 620                                 <filename>exit.target</filename> unit
 621                                 when this signal is received. This is
 622                                 mostly equivalent to
 623                                 <command>systemctl --user start
 624                                 exit.target</command>.</para></listitem>
 625                         </varlistentry>
 626
 627                         <varlistentry>
 628                                 <term>SIGINT</term>
 629
 630                                 <listitem><para>Upon receiving this
 631                                 signal the systemd system manager will
 632                                 start the
 633                                 <filename>ctrl-alt-del.target</filename> unit. This
 634                                 is mostly equivalent to
 635                                 <command>systemctl start
 636                                 ctl-alt-del.target</command>.</para>
 637
 638                                 <para>systemd user managers
 639                                 treat this signal the same way as
 640                                 SIGTERM.</para></listitem>
 641                         </varlistentry>
 642
 643                         <varlistentry>
 644                                 <term>SIGWINCH</term>
 645
 646                                 <listitem><para>When this signal is
 647                                 received the systemd system manager
 648                                 will start the
 649                                 <filename>kbrequest.target</filename>
 650                                 unit. This is mostly equivalent to
 651                                 <command>systemctl start
 652                                 kbrequest.target</command>.</para>
 653
 654                                 <para>This signal is ignored by
 655                                 systemd user
 656                                 managers.</para></listitem>
 657                         </varlistentry>
 658
 659                         <varlistentry>
 660                                 <term>SIGPWR</term>
 661
 662                                 <listitem><para>When this signal is
 663                                 received the systemd manager
 664                                 will start the
 665                                 <filename>sigpwr.target</filename>
 666                                 unit. This is mostly equivalent to
 667                                 <command>systemctl start
 668                                 sigpwr.target</command>.</para></listitem>
 669                         </varlistentry>
 670
 671                         <varlistentry>
 672                                 <term>SIGUSR1</term>
 673
 674                                 <listitem><para>When this signal is
 675                                 received the systemd manager will try
 676                                 to reconnect to the D-Bus
 677                                 bus.</para></listitem>
 678                         </varlistentry>
 679
 680                         <varlistentry>
 681                                 <term>SIGUSR2</term>
 682
 683                                 <listitem><para>When this signal is
 684                                 received the systemd manager will log
 685                                 its complete state in human readable
 686                                 form. The data logged is the same as
 687                                 printed by <command>systemctl
 688                                 dump</command>.</para></listitem>
 689                         </varlistentry>
 690
 691                         <varlistentry>
 692                                 <term>SIGHUP</term>
 693
 694                                 <listitem><para>Reloads the complete
 695                                 daemon configuration. This is mostly
 696                                 equivalent to <command>systemctl
 697                                 daemon-reload</command>.</para></listitem>
 698                         </varlistentry>
 699
 700                         <varlistentry>
 701                                 <term>SIGRTMIN+0</term>
 702
 703                                 <listitem><para>Enters default mode, starts the
 704                                 <filename>default.target</filename>
 705                                 unit. This is mostly equivalent to
 706                                 <command>systemctl start
 707                                 default.target</command>.</para></listitem>
 708                         </varlistentry>
 709
 710                         <varlistentry>
 711                                 <term>SIGRTMIN+1</term>
 712
 713                                 <listitem><para>Enters rescue mode,
 714                                 starts the
 715                                 <filename>rescue.target</filename>
 716                                 unit. This is mostly equivalent to
 717                                 <command>systemctl isolate
 718                                 rescue.target</command>.</para></listitem>
 719                         </varlistentry>
 720
 721                         <varlistentry>
 722                                 <term>SIGRTMIN+2</term>
 723
 724                                 <listitem><para>Enters emergency mode,
 725                                 starts the
 726                                 <filename>emergency.service</filename>
 727                                 unit. This is mostly equivalent to
 728                                 <command>systemctl isolate
 729                                 emergency.service</command>.</para></listitem>
 730                         </varlistentry>
 731
 732                         <varlistentry>
 733                                 <term>SIGRTMIN+3</term>
 734
 735                                 <listitem><para>Halts the machine,
 736                                 starts the
 737                                 <filename>halt.target</filename>
 738                                 unit. This is mostly equivalent to
 739                                 <command>systemctl start
 740                                 halt.target</command>.</para></listitem>
 741                         </varlistentry>
 742
 743                         <varlistentry>
 744                                 <term>SIGRTMIN+4</term>
 745
 746                                 <listitem><para>Powers off the machine,
 747                                 starts the
 748                                 <filename>poweroff.target</filename>
 749                                 unit. This is mostly equivalent to
 750                                 <command>systemctl start
 751                                 poweroff.target</command>.</para></listitem>
 752                         </varlistentry>
 753
 754                         <varlistentry>
 755                                 <term>SIGRTMIN+5</term>
 756
 757                                 <listitem><para>Reboots the machine,
 758                                 starts the
 759                                 <filename>reboot.target</filename>
 760                                 unit. This is mostly equivalent to
 761                                 <command>systemctl start
 762                                 reboot.target</command>.</para></listitem>
 763                         </varlistentry>
 764
 765                         <varlistentry>
 766                                 <term>SIGRTMIN+6</term>
 767
 768                                 <listitem><para>Reboots the machine via kexec,
 769                                 starts the
 770                                 <filename>kexec.target</filename>
 771                                 unit. This is mostly equivalent to
 772                                 <command>systemctl start
 773                                 kexec.target</command>.</para></listitem>
 774                         </varlistentry>
 775
 776                         <varlistentry>
 777                                 <term>SIGRTMIN+13</term>
 778
 779                                 <listitem><para>Immediately halts the machine.</para></listitem>
 780                         </varlistentry>
 781
 782                         <varlistentry>
 783                                 <term>SIGRTMIN+14</term>
 784
 785                                 <listitem><para>Immediately powers off the machine.</para></listitem>
 786                         </varlistentry>
 787
 788                         <varlistentry>
 789                                 <term>SIGRTMIN+15</term>
 790
 791                                 <listitem><para>Immediately reboots the machine.</para></listitem>
 792                         </varlistentry>
 793
 794                         <varlistentry>
 795                                 <term>SIGRTMIN+16</term>
 796
 797                                 <listitem><para>Immediately reboots the machine with kexec.</para></listitem>
 798                         </varlistentry>
 799
 800                         <varlistentry>
 801                                 <term>SIGRTMIN+20</term>
 802
 803                                 <listitem><para>Enables display of
 804                                 status messages on the console, as
 805                                 controlled via
 806                                 <varname>systemd.show_status=1</varname>
 807                                 on the kernel command
 808                                 line.</para></listitem>
 809                         </varlistentry>
 810
 811                         <varlistentry>
 812                                 <term>SIGRTMIN+21</term>
 813
 814                                 <listitem><para>Disables display of
 815                                 status messages on the console, as
 816                                 controlled via
 817                                 <varname>systemd.show_status=0</varname>
 818                                 on the kernel command
 819                                 line.</para></listitem>
 820                         </varlistentry>
 821
 822                         <varlistentry>
 823                                 <term>SIGRTMIN+22</term>
 824                                 <term>SIGRTMIN+23</term>
 825
 826                                 <listitem><para>Sets the log level to
 827                                 <literal>debug</literal>
 828                                 (resp. <literal>info</literal> on
 829                                 <literal>SIGRTMIN+23</literal>), as
 830                                 controlled via
 831                                 <varname>systemd.log_level=debug</varname>
 832                                 (resp. <varname>systemd.log_level=info</varname>
 833                                 on <literal>SIGRTMIN+23</literal>) on
 834                                 the kernel command
 835                                 line.</para></listitem>
 836                         </varlistentry>
 837
 838                         <varlistentry>
 839                                 <term>SIGRTMIN+26</term>
 840                                 <term>SIGRTMIN+27</term>
 841                                 <term>SIGRTMIN+28</term>
 842                                 <term>SIGRTMIN+29</term>
 843
 844                                 <listitem><para>Sets the log level to
 845                                 <literal>journal-or-kmsg</literal>
 846                                 (resp. <literal>console</literal> on
 847                                 <literal>SIGRTMIN+27</literal>;
 848                                 resp. <literal>kmsg</literal> on
 849                                 <literal>SIGRTMIN+28</literal>;
 850                                 resp. <literal>syslog-or-kmsg</literal>
 851                                 on <literal>SIGRTMIN+29</literal>), as
 852                                 controlled via
 853                                 <varname>systemd.log_target=journal-or-kmsg</varname>
 854                                 (resp. <varname>systemd.log_target=console</varname>
 855                                 on <literal>SIGRTMIN+27</literal>;
 856                                 resp. <varname>systemd.log_target=kmsg</varname>
 857                                 on <literal>SIGRTMIN+28</literal>;
 858                                 resp
 859                                 <varname>systemd.log_target=syslog-or-kmsg</varname>
 860                                 on <literal>SIGRTMIN+29</literal>) on
 861                                 the kernel command
 862                                 line.</para></listitem>
 863                         </varlistentry>
 864                 </variablelist>
 865         </refsect1>
 866
 867         <refsect1>
 868                 <title>Environment</title>
 869
 870                 <variablelist>
 871                         <varlistentry>
 872                                 <term><varname>$SYSTEMD_LOG_LEVEL</varname></term>
 873                                 <listitem><para>systemd reads the
 874                                 log level from this environment
 875                                 variable. This can be overridden with
 876                                 <option>--log-level=</option>.</para></listitem>
 877                         </varlistentry>
 878
 879                         <varlistentry>
 880                                 <term><varname>$SYSTEMD_LOG_TARGET</varname></term>
 881                                 <listitem><para>systemd reads the
 882                                 log target from this environment
 883                                 variable. This can be overridden with
 884                                 <option>--log-target=</option>.</para></listitem>
 885                         </varlistentry>
 886
 887                         <varlistentry>
 888                                 <term><varname>$SYSTEMD_LOG_COLOR</varname></term>
 889                                 <listitem><para>Controls whether
 890                                 systemd highlights important log
 891                                 messages. This can be overridden with
 892                                 <option>--log-color=</option>.</para></listitem>
 893                         </varlistentry>
 894
 895                         <varlistentry>
 896                                 <term><varname>$SYSTEMD_LOG_LOCATION</varname></term>
 897                                 <listitem><para>Controls whether
 898                                 systemd prints the code location along
 899                                 with log messages. This can be
 900                                 overridden with
 901                                 <option>--log-location=</option>.</para></listitem>
 902                         </varlistentry>
 903
 904                         <varlistentry>
 905                                 <term><varname>$XDG_CONFIG_HOME</varname></term>
 906                                 <term><varname>$XDG_CONFIG_DIRS</varname></term>
 907                                 <term><varname>$XDG_DATA_HOME</varname></term>
 908                                 <term><varname>$XDG_DATA_DIRS</varname></term>
 909
 910                                 <listitem><para>The systemd user
 911                                 manager uses these variables in
 912                                 accordance to the <ulink
 913                                 url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
 914                                 Base Directory specification</ulink>
 915                                 to find its configuration.</para></listitem>
 916                         </varlistentry>
 917
 918                         <varlistentry>
 919                                 <term><varname>$SYSTEMD_UNIT_PATH</varname></term>
 920
 921                                 <listitem><para>Controls where systemd
 922                                 looks for unit
 923                                 files.</para></listitem>
 924                         </varlistentry>
 925
 926                         <varlistentry>
 927                                 <term><varname>$SYSTEMD_SYSVINIT_PATH</varname></term>
 928
 929                                 <listitem><para>Controls where systemd
 930                                 looks for SysV init scripts.</para></listitem>
 931                         </varlistentry>
 932
 933                         <varlistentry>
 934                                 <term><varname>$SYSTEMD_SYSVRCND_PATH</varname></term>
 935
 936                                 <listitem><para>Controls where systemd
 937                                 looks for SysV init script runlevel link
 938                                 farms.</para></listitem>
 939                         </varlistentry>
 940
 941                         <varlistentry>
 942                                 <term><varname>$LISTEN_PID</varname></term>
 943                                 <term><varname>$LISTEN_FDS</varname></term>
 944
 945                                 <listitem><para>Set by systemd for
 946                                 supervised processes during
 947                                 socket-based activation. See
 948                                 <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 949                                 for more information.
 950                                 </para></listitem>
 951                         </varlistentry>
 952
 953                         <varlistentry>
 954                                 <term><varname>$NOTIFY_SOCKET</varname></term>
 955
 956                                 <listitem><para>Set by systemd for
 957                                 supervised processes for status and
 958                                 start-up completion notification. See
 959                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 960                                 for more information.
 961                                 </para></listitem>
 962                         </varlistentry>
 963                 </variablelist>
 964         </refsect1>
 965
 966         <refsect1>
 967                 <title>Kernel Command Line</title>
 968
 969                 <para>When run as system instance systemd parses a
 970                 number of kernel command line
 971                 arguments<footnote><para>If run inside a Linux
 972                 container these arguments may be passed as command
 973                 line arguments to systemd itself, next to any of the
 974                 command line options listed in the Options section
 975                 above. If run outside of Linux containers, these
 976                 arguments are parsed from
 977                 <filename>/proc/cmdline</filename>
 978                 instead.</para></footnote>:</para>
 979
 980                 <variablelist>
 981                         <varlistentry>
 982                                 <term><varname>systemd.unit=</varname></term>
 983                                 <term><varname>rd.systemd.unit=</varname></term>
 984
 985                                 <listitem><para>Overrides the unit to
 986                                 activate on boot. Defaults to
 987                                 <filename>default.target</filename>. This
 988                                 may be used to temporarily boot into a
 989                                 different boot unit, for example
 990                                 <filename>rescue.target</filename> or
 991                                 <filename>emergency.service</filename>. See
 992                                 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 993                                 for details about these units. The
 994                                 option prefixed with
 995                                 <literal>rd.</literal> is honoured
 996                                 only in the initial RAM disk (initrd),
 997                                 while the one that isn't prefixed only
 998                                 in the main system.</para></listitem>
 999                         </varlistentry>
1000
1001                         <varlistentry>
1002                                 <term><varname>systemd.dump_core=</varname></term>
1003
1004                                 <listitem><para>Takes a boolean
1005                                 argument. If <option>true</option>
1006                                 systemd dumps core when it
1007                                 crashes. Otherwise no core dump is
1008                                 created. Defaults to
1009                                 <option>true</option>.</para></listitem>
1010                         </varlistentry>
1011
1012                         <varlistentry>
1013                                 <term><varname>systemd.crash_shell=</varname></term>
1014
1015                                 <listitem><para>Takes a boolean
1016                                 argument. If <option>true</option>
1017                                 systemd spawns a shell when it
1018                                 crashes. Otherwise no shell is
1019                                 spawned. Defaults to
1020                                 <option>false</option>, for security
1021                                 reasons, as the shell is not protected
1022                                 by any password
1023                                 authentication.</para></listitem>
1024                         </varlistentry>
1025
1026                         <varlistentry>
1027                                 <term><varname>systemd.crash_chvt=</varname></term>
1028
1029                                 <listitem><para>Takes an integer
1030                                 argument. If positive systemd
1031                                 activates the specified virtual
1032                                 terminal when it crashes. Defaults to
1033                                 <literal>-1</literal>.</para></listitem>
1034                         </varlistentry>
1035
1036                         <varlistentry>
1037                                 <term><varname>systemd.confirm_spawn=</varname></term>
1038
1039                                 <listitem><para>Takes a boolean
1040                                 argument. If <option>true</option>
1041                                 asks for confirmation when spawning
1042                                 processes. Defaults to
1043                                 <option>false</option>.</para></listitem>
1044                         </varlistentry>
1045
1046                         <varlistentry>
1047                                 <term><varname>systemd.show_status=</varname></term>
1048
1049                                 <listitem><para>Takes a boolean
1050                                 argument. If <option>true</option>
1051                                 shows terse service status updates on
1052                                 the console during bootup. Defaults to
1053                                 <option>true</option>, unless
1054                                 <option>quiet</option> is passed as
1055                                 kernel command line option in which
1056                                 case it defaults to
1057                                 <option>false</option>.</para></listitem>
1058                         </varlistentry>
1059
1060                         <varlistentry>
1061                                 <term><varname>systemd.log_target=</varname></term>
1062                                 <term><varname>systemd.log_level=</varname></term>
1063                                 <term><varname>systemd.log_color=</varname></term>
1064                                 <term><varname>systemd.log_location=</varname></term>
1065
1066                                 <listitem><para>Controls log output,
1067                                 with the same effect as the
1068                                 <varname>$SYSTEMD_LOG_TARGET</varname>, <varname>$SYSTEMD_LOG_LEVEL</varname>, <varname>$SYSTEMD_LOG_COLOR</varname>, <varname>$SYSTEMD_LOG_LOCATION</varname>
1069                                 environment variables described above.</para></listitem>
1070                         </varlistentry>
1071
1072                         <varlistentry>
1073                                 <term><varname>systemd.default_standard_output=</varname></term>
1074                                 <term><varname>systemd.default_standard_error=</varname></term>
1075                                 <listitem><para>Controls default
1076                                 standard output/error output for
1077                                 services, with the same effect as the
1078                                 <option>--default-standard-output=</option>
1079                                 resp. <option>--default-standard-error=</option>
1080                                 command line arguments described
1081                                 above.</para></listitem>
1082                         </varlistentry>
1083
1084                         <varlistentry>
1085                                 <term><varname>systemd.setenv=</varname></term>
1086
1087                                 <listitem><para>Takes a string
1088                                 argument in the form
1089                                 VARIABLE=VALUE. May be used to set
1090                                 environment variables for the init
1091                                 process and all its children at boot
1092                                 time. May be used more than once to
1093                                 set multiple variables. If the equal
1094                                 sign and variable are missing unsets
1095                                 an environment variable which might be
1096                                 passed in from the initial ram
1097                                 disk.</para></listitem>
1098                         </varlistentry>
1099
1100                         <varlistentry>
1101                                 <term><varname>quiet</varname></term>
1102
1103                                 <listitem><para>If passed turns off
1104                                 status output at boot, much like
1105                                 <varname>systemd.show_status=false</varname>
1106                                 would. Note that this option is also
1107                                 read by the kernel itself and disables
1108                                 kernel log output to the
1109                                 kernel. Passing this option hence
1110                                 turns off the usual output from both
1111                                 the system manager and the
1112                                 kernel.</para></listitem>
1113                         </varlistentry>
1114
1115                         <varlistentry>
1116                                 <term><varname>emergency</varname></term>
1117
1118                                 <listitem><para>Boot into emergency
1119                                 mode. This is equivalent to
1120                                 <varname>systemd.unit=emergency.target</varname>
1121                                 and provided for compatibility
1122                                 reasons and to be easier to type.</para></listitem>
1123                         </varlistentry>
1124
1125                         <varlistentry>
1126                                 <term><varname>single</varname></term>
1127                                 <term><varname>s</varname></term>
1128                                 <term><varname>S</varname></term>
1129                                 <term><varname>1</varname></term>
1130
1131                                 <listitem><para>Boot into rescue
1132                                 mode. This is equivalent to
1133                                 <varname>systemd.unit=rescue.target</varname>
1134                                 and provided for compatibility reasons
1135                                 and to be easier to
1136                                 type.</para></listitem>
1137                         </varlistentry>
1138
1139                         <varlistentry>
1140                                 <term><varname>2</varname></term>
1141                                 <term><varname>3</varname></term>
1142                                 <term><varname>4</varname></term>
1143                                 <term><varname>5</varname></term>
1144
1145                                 <listitem><para>Boot into the
1146                                 specified legacy SysV runlevel. This
1147                                 is equivalent to
1148                                 <varname>systemd.unit=runlevel2.target</varname>,
1149                                 <varname>systemd.unit=runlevel3.target</varname>,
1150                                 <varname>systemd.unit=runlevel4.target</varname>,
1151                                 resp. <varname>systemd.unit=runlevel5.target</varname>
1152                                 and provided for compatibility reasons
1153                                 and to be easier to
1154                                 type.</para></listitem>
1155                         </varlistentry>
1156
1157                         <varlistentry>
1158                                 <term><varname>locale.LANG=</varname></term>
1159                                 <term><varname>locale.LANGUAGE=</varname></term>
1160                                 <term><varname>locale.LC_CTYPE=</varname></term>
1161                                 <term><varname>locale.LC_NUMERIC=</varname></term>
1162                                 <term><varname>locale.LC_TIME=</varname></term>
1163                                 <term><varname>locale.LC_COLLATE=</varname></term>
1164                                 <term><varname>locale.LC_MONETARY=</varname></term>
1165                                 <term><varname>locale.LC_MESSAGES=</varname></term>
1166                                 <term><varname>locale.LC_PAPER=</varname></term>
1167                                 <term><varname>locale.LC_NAME=</varname></term>
1168                                 <term><varname>locale.LC_ADDRESS=</varname></term>
1169                                 <term><varname>locale.LC_TELEPHONE=</varname></term>
1170                                 <term><varname>locale.LC_MEASUREMENT=</varname></term>
1171                                 <term><varname>locale.LC_IDENTIFICATION=</varname></term>
1172
1173                                 <listitem><para>Set the system locale
1174                                 to use. This overrides the settings in
1175                                 <filename>/etc/locale.conf</filename>. For
1176                                 more information see
1177                                 <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1178                                 and
1179                                 <citerefentry><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
1180                                 </para></listitem>
1181                         </varlistentry>
1182                 </variablelist>
1183
1184                 <para>For other kernel command line parameters
1185                 understood by components of the core OS, please refer
1186                 to
1187                 <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
1188         </refsect1>
1189
1190         <refsect1>
1191                 <title>Sockets and FIFOs</title>
1192
1193                 <variablelist>
1194                         <varlistentry>
1195                                 <term><filename>/run/systemd/notify</filename></term>
1196
1197                                 <listitem><para>Daemon status
1198                                 notification socket. This is an
1199                                 AF_UNIX datagram socket and is used to
1200                                 implement the daemon notification
1201                                 logic as implemented by
1202                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
1203
1204                         </varlistentry>
1205
1206                         <varlistentry>
1207                                 <term><filename>/run/systemd/shutdownd</filename></term>
1208
1209                                 <listitem><para>Used internally by the
1210                                 <citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>8</manvolnum></citerefentry>
1211                                 tool to implement delayed
1212                                 shutdowns. This is an AF_UNIX datagram
1213                                 socket.</para></listitem>
1214                         </varlistentry>
1215
1216                         <varlistentry>
1217                                 <term><filename>/run/systemd/private</filename></term>
1218
1219                                 <listitem><para>Used internally as
1220                                 communication channel between
1221                                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1222                                 and the systemd process. This is an
1223                                 AF_UNIX stream socket. This interface
1224                                 is private to systemd and should not
1225                                 be used in external
1226                                 projects.</para></listitem>
1227                         </varlistentry>
1228
1229                         <varlistentry>
1230                                 <term><filename>/dev/initctl</filename></term>
1231
1232                                 <listitem><para>Limited compatibility
1233                                 support for the SysV client interface,
1234                                 as implemented by the
1235                                 <filename>systemd-initctl.service</filename>
1236                                 unit. This is a named pipe in the file
1237                                 system. This interface is obsolete and
1238                                 should not be used in new
1239                                 applications.</para></listitem>
1240                         </varlistentry>
1241                 </variablelist>
1242         </refsect1>
1243
1244         <refsect1>
1245                 <title>See Also</title>
1246                 <para>
1247                         <citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1248                         <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1249                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1250                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1251                         <citerefentry><refentrytitle>systemd-notify</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1252                         <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1253                         <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
1254                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1255                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1256                         <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1257                         <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1258                         <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>
1259                 </para>
1260         </refsect1>
1261
1262 </refentry>