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