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1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4
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           xmlns:xi="http://www.w3.org/2001/XInclude">
26
27         <refentryinfo>
28                 <title>systemd</title>
29                 <productname>systemd</productname>
30
31                 <authorgroup>
32                         <author>
33                                 <contrib>Developer</contrib>
34                                 <firstname>Lennart</firstname>
35                                 <surname>Poettering</surname>
36                                 <email>lennart@poettering.net</email>
37                         </author>
38                 </authorgroup>
39         </refentryinfo>
40
41         <refmeta>
42                 <refentrytitle>systemd</refentrytitle>
43                 <manvolnum>1</manvolnum>
44         </refmeta>
45
46         <refnamediv>
47                 <refname>systemd</refname>
48                 <refname>init</refname>
49                 <refpurpose>systemd system and service manager</refpurpose>
50         </refnamediv>
51
52         <refsynopsisdiv>
53                 <cmdsynopsis>
54                         <command>systemd <arg choice="opt" rep="repeat">OPTIONS</arg></command>
55                 </cmdsynopsis>
56                 <cmdsynopsis>
57                         <command>init <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg></command>
58                 </cmdsynopsis>
59         </refsynopsisdiv>
60
61         <refsect1>
62                 <title>Description</title>
63
64                 <para>systemd is a system and service manager for
65                 Linux operating systems. When run as first process on
66                 boot (as PID 1), it acts as init system that brings
67                 up and maintains userspace services.</para>
68
69                 <para>For compatibility with SysV, if systemd is called
70                 as <command>init</command> and a PID that is not
71                 1, it will execute <command>telinit</command> and pass
72                 all command line arguments unmodified. That means
73                 <command>init</command> and <command>telinit</command>
74                 are mostly equivalent when invoked from normal login sessions. See
75                 <citerefentry><refentrytitle>telinit</refentrytitle><manvolnum>8</manvolnum></citerefentry>
76                 for more information.</para>
77
78                 <para>When run as system instance, systemd interprets
79                 the configuration file
80                 <filename>system.conf</filename>, otherwise
81                 <filename>user.conf</filename>. See
82                 <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
83                 for more information.</para>
84         </refsect1>
85
86         <refsect1>
87                 <title>Options</title>
88
89                 <para>The following options are understood:</para>
90
91                 <variablelist>
92                         <varlistentry>
93                                 <term><option>--test</option></term>
94
95                                 <listitem><para>Determine startup
96                                 sequence, dump it and exit. This is an
97                                 option useful for debugging
98                                 only.</para></listitem>
99                         </varlistentry>
100                         <varlistentry>
101                                 <term><option>--dump-configuration-items</option></term>
102
103                                 <listitem><para>Dump understood unit
104                                 configuration items. This outputs a
105                                 terse but complete list of
106                                 configuration items understood in unit
107                                 definition files.</para></listitem>
108                         </varlistentry>
109                         <varlistentry>
110                                 <term><option>--unit=</option></term>
111
112                                 <listitem><para>Set default unit to
113                                 activate on startup. If not specified,
114                                 defaults to
115                                 <filename>default.target</filename>.</para></listitem>
116                         </varlistentry>
117                         <varlistentry>
118                                 <term><option>--system</option></term>
119                                 <term><option>--user</option></term>
120
121                                 <listitem><para>For <option>--system</option>,
122                                 tell systemd to run a
123                                 system instance, even if the process ID is
124                                 not 1, i.e. systemd is not run as init process.
125                                 <option>--user</option> does the opposite,
126                                 running a user instance even if the process
127                                 ID is 1.
128                                 Normally it should not be necessary to
129                                 pass these options, as systemd
130                                 automatically detects the mode it is
131                                 started in. These options are hence of
132                                 little use except for debugging. Note
133                                 that it is not supported booting and
134                                 maintaining a full system with systemd
135                                 running in <option>--system</option>
136                                 mode, but PID not 1. In practice,
137                                 passing <option>--system</option> explicitly is
138                                 only useful in conjunction with
139                                 <option>--test</option>.</para></listitem>
140                         </varlistentry>
141                         <varlistentry>
142                                 <term><option>--dump-core</option></term>
143
144                                 <listitem><para>Dump core on
145                                 crash. This switch has no effect when
146                                 run as user
147                                 instance.</para></listitem>
148                         </varlistentry>
149                         <varlistentry>
150                                 <term><option>--crash-shell</option></term>
151
152                                 <listitem><para>Run shell on
153                                 crash. This switch has no effect when
154                                 run as user
155                                 instance.</para></listitem>
156                         </varlistentry>
157                         <varlistentry>
158                                 <term><option>--confirm-spawn</option></term>
159
160                                 <listitem><para>Ask for confirmation
161                                 when spawning processes. This switch
162                                 has no effect when run as user
163                                 instance.</para></listitem>
164                         </varlistentry>
165                         <varlistentry>
166                                 <term><option>--show-status=</option></term>
167
168                                 <listitem><para>Show terse service
169                                 status information while booting. This
170                                 switch has no effect when run as user
171                                 instance. Takes a boolean argument
172                                 which may be omitted which is
173                                 interpreted as
174                                 <option>true</option>.</para></listitem>
175                         </varlistentry>
176                         <varlistentry>
177                                 <term><option>--log-target=</option></term>
178
179                                 <listitem><para>Set log
180                                 target. Argument must be one of
181                                 <option>console</option>,
182                                 <option>journal</option>,
183                                 <option>syslog</option>,
184                                 <option>kmsg</option>,
185                                 <option>journal-or-kmsg</option>,
186                                 <option>syslog-or-kmsg</option>,
187                                 <option>null</option>.</para></listitem>
188                         </varlistentry>
189                         <varlistentry>
190                                 <term><option>--log-level=</option></term>
191
192                                 <listitem><para>Set log level. As
193                                 argument this accepts a numerical log
194                                 level or the well-known <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
195                                 symbolic names (lowercase):
196                                 <option>emerg</option>,
197                                 <option>alert</option>,
198                                 <option>crit</option>,
199                                 <option>err</option>,
200                                 <option>warning</option>,
201                                 <option>notice</option>,
202                                 <option>info</option>,
203                                 <option>debug</option>.</para></listitem>
204                         </varlistentry>
205                         <varlistentry>
206                                 <term><option>--log-color=</option></term>
207
208                                 <listitem><para>Highlight important
209                                 log messages. Argument is a boolean
210                                 value. If the argument is omitted, it
211                                 defaults to
212                                 <option>true</option>.</para></listitem>
213                         </varlistentry>
214                         <varlistentry>
215                                 <term><option>--log-location=</option></term>
216
217                                 <listitem><para>Include code location
218                                 in log messages. This is mostly
219                                 relevant for debugging
220                                 purposes. Argument is a boolean
221                                 value. If the argument is omitted
222                                 it defaults to
223                                 <option>true</option>.</para></listitem>
224                         </varlistentry>
225                         <varlistentry>
226                                 <term><option>--default-standard-output=</option></term>
227                                 <term><option>--default-standard-error=</option></term>
228
229                                 <listitem><para>Sets the default
230                                 output or error output for all
231                                 services and sockets, respectively. That is, controls
232                                 the default for
233                                 <option>StandardOutput=</option>
234                                 and <option>StandardError=</option>
235                                 (see
236                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
237                                 for details). Takes one of
238                                 <option>inherit</option>,
239                                 <option>null</option>,
240                                 <option>tty</option>,
241                                 <option>journal</option>,
242                                 <option>journal+console</option>,
243                                 <option>syslog</option>,
244                                 <option>syslog+console</option>,
245                                 <option>kmsg</option>,
246                                 <option>kmsg+console</option>.  If the
247                                 argument is omitted
248                                 <option>--default-standard-output=</option>
249                                 defaults to <option>journal</option>
250                                 and
251                                 <option>--default-standard-error=</option>
252                                 to
253                                 <option>inherit</option>.</para></listitem>
254                         </varlistentry>
255
256                         <xi:include href="standard-options.xml" xpointer="help" />
257                         <xi:include href="standard-options.xml" xpointer="version" />
258                 </variablelist>
259         </refsect1>
260
261         <refsect1>
262                 <title>Concepts</title>
263
264                 <para>systemd provides a dependency system between
265                 various entities called "units" of 12 different
266                 types. Units encapsulate various objects that are
267                 relevant for system boot-up and maintenance. The
268                 majority of units are configured in unit configuration
269                 files, whose syntax and basic set of options is
270                 described in
271                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
272                 however some are created automatically from other
273                 configuration, dynamically from system state or
274                 programmatically at runtime. Units may be "active"
275                 (meaning started, bound, plugged in, ..., depending on
276                 the unit type, see below), or "inactive" (meaning
277                 stopped, unbound, unplugged, ...), as well as in the
278                 process of being activated or deactivated,
279                 i.e. between the two states (these states are called
280                 "activating", "deactivating"). A special "failed"
281                 state is available as well, which is very similar to
282                 "inactive" and is entered when the service failed in
283                 some way (process returned error code on exit, or
284                 crashed, or an operation timed out). If this state is
285                 entered, the cause will be logged, for later
286                 reference. Note that the various unit types may have a
287                 number of additional substates, which are mapped to
288                 the five generalized unit states described
289                 here.</para>
290
291                 <para>The following unit types are available:</para>
292
293                 <orderedlist>
294                         <listitem><para>Service units, which start and control
295                         daemons and the processes they consist of. For
296                         details see
297                         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
298
299                         <listitem><para>Socket units, which
300                         encapsulate local IPC or network sockets in
301                         the system, useful for socket-based
302                         activation. For details about socket units see
303                         <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
304                         for details on socket-based activation and
305                         other forms of activation, see
306                         <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem>
307
308                         <listitem><para>Target units are useful to
309                         group units, or provide well-known
310                         synchronization points during boot-up, see
311                         <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
312
313                         <listitem><para>Device units expose kernel
314                         devices in systemd and may be used to
315                         implement device-based activation. For details
316                         see
317                         <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
318
319                         <listitem><para>Mount units control mount
320                         points in the file system, for details see
321                         <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
322
323                         <listitem><para>Automount units provide
324                         automount capabilities, for on-demand mounting
325                         of file systems as well as parallelized
326                         boot-up. See
327                         <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
328
329                         <listitem><para>Snapshot units can be used to
330                         temporarily save the state of the set of
331                         systemd units, which later may be restored by
332                         activating the saved snapshot unit. For more
333                         information see
334                         <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
335
336                         <listitem><para>Timer units are useful for
337                         triggering activation of other units based on
338                         timers. You may find details in
339                         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
340
341                         <listitem><para>Swap units are very similar to
342                         mount units and encapsulate memory swap
343                         partitions or files of the operating
344                         system. They are described in <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
345
346                         <listitem><para>Path units may be used
347                         to activate other services when file system
348                         objects change or are modified. See
349                         <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
350
351                         <listitem><para>Slice units may be used to
352                         group units which manage system processes
353                         (such as service and scope units) in a
354                         hierarchical tree for resource management
355                         purposes. See
356                         <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
357
358                         <listitem><para>Scope units are similar to
359                         service units, but manage foreign processes
360                         instead of starting them as well. See
361                         <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
362
363                 </orderedlist>
364
365                 <para>Units are named as their configuration
366                 files. Some units have special semantics. A detailed
367                 list is available in
368                 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
369
370                 <para>systemd knows various kinds of dependencies,
371                 including positive and negative requirement
372                 dependencies (i.e. <varname>Requires=</varname> and
373                 <varname>Conflicts=</varname>) as well as ordering
374                 dependencies (<varname>After=</varname> and
375                 <varname>Before=</varname>). NB: ordering and
376                 requirement dependencies are orthogonal. If only a
377                 requirement dependency exists between two units
378                 (e.g. <filename>foo.service</filename> requires
379                 <filename>bar.service</filename>), but no ordering
380                 dependency (e.g. <filename>foo.service</filename>
381                 after <filename>bar.service</filename>) and both are
382                 requested to start, they will be started in
383                 parallel. It is a common pattern that both requirement
384                 and ordering dependencies are placed between two
385                 units. Also note that the majority of dependencies are
386                 implicitly created and maintained by systemd. In most
387                 cases, it should be unnecessary to declare additional
388                 dependencies manually, however it is possible to do
389                 this.</para>
390
391                 <para>Application programs and units (via
392                 dependencies) may request state changes of units. In
393                 systemd, these requests are encapsulated as 'jobs' and
394                 maintained in a job queue. Jobs may succeed or can
395                 fail, their execution is ordered based on the ordering
396                 dependencies of the units they have been scheduled
397                 for.</para>
398
399                 <para>On boot systemd activates the target unit
400                 <filename>default.target</filename> whose job is to
401                 activate on-boot services and other on-boot units by
402                 pulling them in via dependencies. Usually the unit
403                 name is just an alias (symlink) for either
404                 <filename>graphical.target</filename> (for
405                 fully-featured boots into the UI) or
406                 <filename>multi-user.target</filename> (for limited
407                 console-only boots for use in embedded or server
408                 environments, or similar; a subset of
409                 graphical.target). However, it is at the discretion of
410                 the administrator to configure it as an alias to any
411                 other target unit. See
412                 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
413                 for details about these target units.</para>
414
415                 <para>Processes systemd spawns are placed in
416                 individual Linux control groups named after the unit
417                 which they belong to in the private systemd
418                 hierarchy. (see <ulink
419                 url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>
420                 for more information about control groups, or short
421                 "cgroups"). systemd uses this to effectively keep
422                 track of processes. Control group information is
423                 maintained in the kernel, and is accessible via the
424                 file system hierarchy (beneath
425                 <filename>/sys/fs/cgroup/systemd/</filename>), or in tools
426                 such as
427                 <citerefentry><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>
428                 (<command>ps xawf -eo pid,user,cgroup,args</command>
429                 is particularly useful to list all processes and the
430                 systemd units they belong to.).</para>
431
432                 <para>systemd is compatible with the SysV init system
433                 to a large degree: SysV init scripts are supported and
434                 simply read as an alternative (though limited)
435                 configuration file format. The SysV
436                 <filename>/dev/initctl</filename> interface is
437                 provided, and compatibility implementations of the
438                 various SysV client tools are available. In addition to
439                 that, various established Unix functionality such as
440                 <filename>/etc/fstab</filename> or the
441                 <filename>utmp</filename> database are
442                 supported.</para>
443
444                 <para>systemd has a minimal transaction system: if a
445                 unit is requested to start up or shut down it will add
446                 it and all its dependencies to a temporary
447                 transaction. Then, it will verify if the transaction
448                 is consistent (i.e. whether the ordering of all units
449                 is cycle-free). If it is not, systemd will try to fix
450                 it up, and removes non-essential jobs from the
451                 transaction that might remove the loop. Also, systemd
452                 tries to suppress non-essential jobs in the
453                 transaction that would stop a running service. Finally
454                 it is checked whether the jobs of the transaction
455                 contradict jobs that have already been queued, and
456                 optionally the transaction is aborted then. If all
457                 worked out and the transaction is consistent and
458                 minimized in its impact it is merged with all already
459                 outstanding jobs and added to the run
460                 queue. Effectively this means that before executing a
461                 requested operation, systemd will verify that it makes
462                 sense, fixing it if possible, and only failing if it
463                 really cannot work.</para>
464
465                 <para>Systemd contains native implementations of
466                 various tasks that need to be executed as part of the
467                 boot process. For example, it sets the hostname or
468                 configures the loopback network device. It also sets
469                 up and mounts various API file systems, such as
470                 <filename>/sys</filename> or
471                 <filename>/proc</filename>.</para>
472
473                 <para>For more information about the concepts and
474                 ideas behind systemd, please refer to the <ulink
475                 url="http://0pointer.de/blog/projects/systemd.html">Original
476                 Design Document</ulink>.</para>
477
478                 <para>Note that some but not all interfaces provided
479                 by systemd are covered by the <ulink
480                 url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
481                 Stability Promise</ulink>.</para>
482
483                 <para>Units may be generated dynamically at boot and
484                 system manager reload time, for example based on other
485                 configuration files or parameters passed on the kernel
486                 command line. For details see the <ulink
487                 url="http://www.freedesktop.org/wiki/Software/systemd/Generators">Generators
488                 Specification</ulink>.</para>
489
490                 <para>Systems which invoke systemd in a container
491                 or initrd environment should implement the
492                 <ulink
493                 url="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container
494                 Interface</ulink> or <ulink
495                 url="http://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd
496                 Interface</ulink> specifications, respectively.</para>
497         </refsect1>
498
499         <refsect1>
500                 <title>Directories</title>
501
502                 <variablelist>
503                         <varlistentry>
504                                 <term>System unit directories</term>
505
506                                 <listitem><para>The systemd system
507                                 manager reads unit configuration from
508                                 various directories. Packages that
509                                 want to install unit files shall place
510                                 them in the directory returned by
511                                 <command>pkg-config systemd
512                                 --variable=systemdsystemunitdir</command>. Other
513                                 directories checked are
514                                 <filename>/usr/local/lib/systemd/system</filename>
515                                 and
516                                 <filename>/usr/lib/systemd/system</filename>. User
517                                 configuration always takes
518                                 precedence. <command>pkg-config
519                                 systemd
520                                 --variable=systemdsystemconfdir</command>
521                                 returns the path of the system
522                                 configuration directory. Packages
523                                 should alter the content of these
524                                 directories only with the
525                                 <command>enable</command> and
526                                 <command>disable</command> commands of
527                                 the
528                                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
529                                 tool. Full list of directories is provided in
530                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
531                                 </para></listitem>
532                         </varlistentry>
533                 </variablelist>
534
535                 <variablelist>
536                         <varlistentry>
537                                 <term>User unit directories</term>
538
539                                 <listitem><para>Similar rules apply
540                                 for the user unit
541                                 directories. However, here the <ulink
542                                 url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
543                                 Base Directory specification</ulink>
544                                 is followed to find
545                                 units. Applications should place their
546                                 unit files in the directory returned
547                                 by <command>pkg-config systemd
548                                 --variable=systemduserunitdir</command>. Global
549                                 configuration is done in the directory
550                                 reported by <command>pkg-config
551                                 systemd
552                                 --variable=systemduserconfdir</command>. The
553                                 <command>enable</command> and
554                                 <command>disable</command> commands of
555                                 the
556                                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
557                                 tool can handle both global (i.e. for
558                                 all users) and private (for one user)
559                                 enabling/disabling of
560                                 units. Full list of directories is provided in
561                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
562                                 </para></listitem>
563                         </varlistentry>
564                 </variablelist>
565
566                 <variablelist>
567                         <varlistentry>
568                                 <term>SysV init scripts directory</term>
569
570                                 <listitem><para>The location of the
571                                 SysV init script directory varies
572                                 between distributions. If systemd
573                                 cannot find a native unit file for a
574                                 requested service, it will look for a
575                                 SysV init script of the same name
576                                 (with the
577                                 <filename>.service</filename> suffix
578                                 removed).</para></listitem>
579                         </varlistentry>
580                 </variablelist>
581
582                 <variablelist>
583                         <varlistentry>
584                                 <term>SysV runlevel link farm directory</term>
585
586                                 <listitem><para>The location of the
587                                 SysV runlevel link farm directory
588                                 varies between distributions. systemd
589                                 will take the link farm into account
590                                 when figuring out whether a service
591                                 shall be enabled. Note that a service
592                                 unit with a native unit configuration
593                                 file cannot be started by activating it
594                                 in the SysV runlevel link
595                                 farm.</para></listitem>
596                         </varlistentry>
597                 </variablelist>
598         </refsect1>
599
600         <refsect1>
601                 <title>Signals</title>
602
603                 <variablelist>
604                         <varlistentry>
605                                 <term><constant>SIGTERM</constant></term>
606
607                                 <listitem><para>Upon receiving this
608                                 signal the systemd system manager
609                                 serializes its state, reexecutes
610                                 itself and deserializes the saved
611                                 state again. This is mostly equivalent
612                                 to <command>systemctl
613                                 daemon-reexec</command>.</para>
614
615                                 <para>systemd user managers will
616                                 start the
617                                 <filename>exit.target</filename> unit
618                                 when this signal is received. This is
619                                 mostly equivalent to
620                                 <command>systemctl --user start
621                                 exit.target</command>.</para></listitem>
622                         </varlistentry>
623
624                         <varlistentry>
625                                 <term><constant>SIGINT</constant></term>
626
627                                 <listitem><para>Upon receiving this
628                                 signal the systemd system manager will
629                                 start the
630                                 <filename>ctrl-alt-del.target</filename> unit. This
631                                 is mostly equivalent to
632                                 <command>systemctl start
633                                 ctl-alt-del.target</command>.</para>
634
635                                 <para>systemd user managers
636                                 treat this signal the same way as
637                                 <constant>SIGTERM</constant>.</para></listitem>
638                         </varlistentry>
639
640                         <varlistentry>
641                                 <term><constant>SIGWINCH</constant></term>
642
643                                 <listitem><para>When this signal is
644                                 received the systemd system manager
645                                 will start the
646                                 <filename>kbrequest.target</filename>
647                                 unit. This is mostly equivalent to
648                                 <command>systemctl start
649                                 kbrequest.target</command>.</para>
650
651                                 <para>This signal is ignored by
652                                 systemd user
653                                 managers.</para></listitem>
654                         </varlistentry>
655
656                         <varlistentry>
657                                 <term><constant>SIGPWR</constant></term>
658
659                                 <listitem><para>When this signal is
660                                 received the systemd manager
661                                 will start the
662                                 <filename>sigpwr.target</filename>
663                                 unit. This is mostly equivalent to
664                                 <command>systemctl start
665                                 sigpwr.target</command>.</para></listitem>
666                         </varlistentry>
667
668                         <varlistentry>
669                                 <term><constant>SIGUSR1</constant></term>
670
671                                 <listitem><para>When this signal is
672                                 received the systemd manager will try
673                                 to reconnect to the D-Bus
674                                 bus.</para></listitem>
675                         </varlistentry>
676
677                         <varlistentry>
678                                 <term><constant>SIGUSR2</constant></term>
679
680                                 <listitem><para>When this signal is
681                                 received the systemd manager will log
682                                 its complete state in human readable
683                                 form. The data logged is the same as
684                                 printed by <command>systemctl
685                                 dump</command>.</para></listitem>
686                         </varlistentry>
687
688                         <varlistentry>
689                                 <term><constant>SIGHUP</constant></term>
690
691                                 <listitem><para>Reloads the complete
692                                 daemon configuration. This is mostly
693                                 equivalent to <command>systemctl
694                                 daemon-reload</command>.</para></listitem>
695                         </varlistentry>
696
697                         <varlistentry>
698                                 <term><constant>SIGRTMIN+0</constant></term>
699
700                                 <listitem><para>Enters default mode, starts the
701                                 <filename>default.target</filename>
702                                 unit. This is mostly equivalent to
703                                 <command>systemctl start
704                                 default.target</command>.</para></listitem>
705                         </varlistentry>
706
707                         <varlistentry>
708                                 <term><constant>SIGRTMIN+1</constant></term>
709
710                                 <listitem><para>Enters rescue mode,
711                                 starts the
712                                 <filename>rescue.target</filename>
713                                 unit. This is mostly equivalent to
714                                 <command>systemctl isolate
715                                 rescue.target</command>.</para></listitem>
716                         </varlistentry>
717
718                         <varlistentry>
719                                 <term><constant>SIGRTMIN+2</constant></term>
720
721                                 <listitem><para>Enters emergency mode,
722                                 starts the
723                                 <filename>emergency.service</filename>
724                                 unit. This is mostly equivalent to
725                                 <command>systemctl isolate
726                                 emergency.service</command>.</para></listitem>
727                         </varlistentry>
728
729                         <varlistentry>
730                                 <term><constant>SIGRTMIN+3</constant></term>
731
732                                 <listitem><para>Halts the machine,
733                                 starts the
734                                 <filename>halt.target</filename>
735                                 unit. This is mostly equivalent to
736                                 <command>systemctl start
737                                 halt.target</command>.</para></listitem>
738                         </varlistentry>
739
740                         <varlistentry>
741                                 <term><constant>SIGRTMIN+4</constant></term>
742
743                                 <listitem><para>Powers off the machine,
744                                 starts the
745                                 <filename>poweroff.target</filename>
746                                 unit. This is mostly equivalent to
747                                 <command>systemctl start
748                                 poweroff.target</command>.</para></listitem>
749                         </varlistentry>
750
751                         <varlistentry>
752                                 <term><constant>SIGRTMIN+5</constant></term>
753
754                                 <listitem><para>Reboots the machine,
755                                 starts the
756                                 <filename>reboot.target</filename>
757                                 unit. This is mostly equivalent to
758                                 <command>systemctl start
759                                 reboot.target</command>.</para></listitem>
760                         </varlistentry>
761
762                         <varlistentry>
763                                 <term><constant>SIGRTMIN+6</constant></term>
764
765                                 <listitem><para>Reboots the machine via kexec,
766                                 starts the
767                                 <filename>kexec.target</filename>
768                                 unit. This is mostly equivalent to
769                                 <command>systemctl start
770                                 kexec.target</command>.</para></listitem>
771                         </varlistentry>
772
773                         <varlistentry>
774                                 <term><constant>SIGRTMIN+13</constant></term>
775
776                                 <listitem><para>Immediately halts the machine.</para></listitem>
777                         </varlistentry>
778
779                         <varlistentry>
780                                 <term><constant>SIGRTMIN+14</constant></term>
781
782                                 <listitem><para>Immediately powers off the machine.</para></listitem>
783                         </varlistentry>
784
785                         <varlistentry>
786                                 <term><constant>SIGRTMIN+15</constant></term>
787
788                                 <listitem><para>Immediately reboots the machine.</para></listitem>
789                         </varlistentry>
790
791                         <varlistentry>
792                                 <term><constant>SIGRTMIN+16</constant></term>
793
794                                 <listitem><para>Immediately reboots the machine with kexec.</para></listitem>
795                         </varlistentry>
796
797                         <varlistentry>
798                                 <term><constant>SIGRTMIN+20</constant></term>
799
800                                 <listitem><para>Enables display of
801                                 status messages on the console, as
802                                 controlled via
803                                 <varname>systemd.show_status=1</varname>
804                                 on the kernel command
805                                 line.</para></listitem>
806                         </varlistentry>
807
808                         <varlistentry>
809                                 <term><constant>SIGRTMIN+21</constant></term>
810
811                                 <listitem><para>Disables display of
812                                 status messages on the console, as
813                                 controlled via
814                                 <varname>systemd.show_status=0</varname>
815                                 on the kernel command
816                                 line.</para></listitem>
817                         </varlistentry>
818
819                         <varlistentry>
820                                 <term><constant>SIGRTMIN+22</constant></term>
821                                 <term><constant>SIGRTMIN+23</constant></term>
822
823                                 <listitem><para>Sets the log level to
824                                 <literal>debug</literal>
825                                 (or <literal>info</literal> on
826                                 <constant>SIGRTMIN+23</constant>), as
827                                 controlled via
828                                 <varname>systemd.log_level=debug</varname>
829                                 (or <varname>systemd.log_level=info</varname>
830                                 on <constant>SIGRTMIN+23</constant>) on
831                                 the kernel command
832                                 line.</para></listitem>
833                         </varlistentry>
834
835                         <varlistentry>
836                                 <term><constant>SIGRTMIN+24</constant></term>
837
838                                 <listitem><para>Immediately exits the
839                                 manager (only available for --user
840                                 instances).</para></listitem>
841                         </varlistentry>
842
843                         <varlistentry>
844                                 <term><constant>SIGRTMIN+26</constant></term>
845                                 <term><constant>SIGRTMIN+27</constant></term>
846                                 <term><constant>SIGRTMIN+28</constant></term>
847                                 <term><constant>SIGRTMIN+29</constant></term>
848
849                                 <listitem><para>Sets the log level to
850                                 <literal>journal-or-kmsg</literal>
851                                 (or <literal>console</literal> on
852                                 <constant>SIGRTMIN+27</constant>,
853                                 <literal>kmsg</literal> on
854                                 <constant>SIGRTMIN+28</constant>,
855                                 or <literal>syslog-or-kmsg</literal>
856                                 on <constant>SIGRTMIN+29</constant>), as
857                                 controlled via
858                                 <varname>systemd.log_target=journal-or-kmsg</varname>
859                                 (or <varname>systemd.log_target=console</varname>
860                                 on <constant>SIGRTMIN+27</constant>,
861                                 <varname>systemd.log_target=kmsg</varname>
862                                 on <constant>SIGRTMIN+28</constant>,
863                                 or
864                                 <varname>systemd.log_target=syslog-or-kmsg</varname>
865                                 on <constant>SIGRTMIN+29</constant>) on
866                                 the kernel command
867                                 line.</para></listitem>
868                         </varlistentry>
869                 </variablelist>
870         </refsect1>
871
872         <refsect1>
873                 <title>Environment</title>
874
875                 <variablelist class='environment-variables'>
876                         <varlistentry>
877                                 <term><varname>$SYSTEMD_LOG_LEVEL</varname></term>
878                                 <listitem><para>systemd reads the
879                                 log level from this environment
880                                 variable. This can be overridden with
881                                 <option>--log-level=</option>.</para></listitem>
882                         </varlistentry>
883
884                         <varlistentry>
885                                 <term><varname>$SYSTEMD_LOG_TARGET</varname></term>
886                                 <listitem><para>systemd reads the
887                                 log target from this environment
888                                 variable. This can be overridden with
889                                 <option>--log-target=</option>.</para></listitem>
890                         </varlistentry>
891
892                         <varlistentry>
893                                 <term><varname>$SYSTEMD_LOG_COLOR</varname></term>
894                                 <listitem><para>Controls whether
895                                 systemd highlights important log
896                                 messages. This can be overridden with
897                                 <option>--log-color=</option>.</para></listitem>
898                         </varlistentry>
899
900                         <varlistentry>
901                                 <term><varname>$SYSTEMD_LOG_LOCATION</varname></term>
902                                 <listitem><para>Controls whether
903                                 systemd prints the code location along
904                                 with log messages. This can be
905                                 overridden with
906                                 <option>--log-location=</option>.</para></listitem>
907                         </varlistentry>
908
909                         <varlistentry>
910                                 <term><varname>$XDG_CONFIG_HOME</varname></term>
911                                 <term><varname>$XDG_CONFIG_DIRS</varname></term>
912                                 <term><varname>$XDG_DATA_HOME</varname></term>
913                                 <term><varname>$XDG_DATA_DIRS</varname></term>
914
915                                 <listitem><para>The systemd user
916                                 manager uses these variables in
917                                 accordance to the <ulink
918                                 url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
919                                 Base Directory specification</ulink>
920                                 to find its configuration.</para></listitem>
921                         </varlistentry>
922
923                         <varlistentry>
924                                 <term><varname>$SYSTEMD_UNIT_PATH</varname></term>
925
926                                 <listitem><para>Controls where systemd
927                                 looks for unit
928                                 files.</para></listitem>
929                         </varlistentry>
930
931                         <varlistentry>
932                                 <term><varname>$SYSTEMD_SYSVINIT_PATH</varname></term>
933
934                                 <listitem><para>Controls where systemd
935                                 looks for SysV init scripts.</para></listitem>
936                         </varlistentry>
937
938                         <varlistentry>
939                                 <term><varname>$SYSTEMD_SYSVRCND_PATH</varname></term>
940
941                                 <listitem><para>Controls where systemd
942                                 looks for SysV init script runlevel link
943                                 farms.</para></listitem>
944                         </varlistentry>
945
946                         <varlistentry>
947                                 <term><varname>$LISTEN_PID</varname></term>
948                                 <term><varname>$LISTEN_FDS</varname></term>
949
950                                 <listitem><para>Set by systemd for
951                                 supervised processes during
952                                 socket-based activation. See
953                                 <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
954                                 for more information.
955                                 </para></listitem>
956                         </varlistentry>
957
958                         <varlistentry>
959                                 <term><varname>$NOTIFY_SOCKET</varname></term>
960
961                                 <listitem><para>Set by systemd for
962                                 supervised processes for status and
963                                 start-up completion notification. See
964                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
965                                 for more information.
966                                 </para></listitem>
967                         </varlistentry>
968                 </variablelist>
969         </refsect1>
970
971         <refsect1>
972                 <title>Kernel Command Line</title>
973
974                 <para>When run as system instance systemd parses a
975                 number of kernel command line
976                 arguments<footnote><para>If run inside a Linux
977                 container these arguments may be passed as command
978                 line arguments to systemd itself, next to any of the
979                 command line options listed in the Options section
980                 above. If run outside of Linux containers, these
981                 arguments are parsed from
982                 <filename>/proc/cmdline</filename>
983                 instead.</para></footnote>:</para>
984
985                 <variablelist class='kernel-commandline-options'>
986                         <varlistentry>
987                                 <term><varname>systemd.unit=</varname></term>
988                                 <term><varname>rd.systemd.unit=</varname></term>
989
990                                 <listitem><para>Overrides the unit to
991                                 activate on boot. Defaults to
992                                 <filename>default.target</filename>. This
993                                 may be used to temporarily boot into a
994                                 different boot unit, for example
995                                 <filename>rescue.target</filename> or
996                                 <filename>emergency.service</filename>. See
997                                 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
998                                 for details about these units. The
999                                 option prefixed with
1000                                 <literal>rd.</literal> is honored
1001                                 only in the initial RAM disk (initrd),
1002                                 while the one that is not prefixed only
1003                                 in the main system.</para></listitem>
1004                         </varlistentry>
1005
1006                         <varlistentry>
1007                                 <term><varname>systemd.dump_core=</varname></term>
1008
1009                                 <listitem><para>Takes a boolean
1010                                 argument. If <option>true</option>,
1011                                 systemd dumps core when it
1012                                 crashes. Otherwise, no core dump is
1013                                 created. Defaults to
1014                                 <option>true</option>.</para></listitem>
1015                         </varlistentry>
1016
1017                         <varlistentry>
1018                                 <term><varname>systemd.crash_shell=</varname></term>
1019
1020                                 <listitem><para>Takes a boolean
1021                                 argument. If <option>true</option>,
1022                                 systemd spawns a shell when it
1023                                 crashes. Otherwise, no shell is
1024                                 spawned. Defaults to
1025                                 <option>false</option>, for security
1026                                 reasons, as the shell is not protected
1027                                 by any password
1028                                 authentication.</para></listitem>
1029                         </varlistentry>
1030
1031                         <varlistentry>
1032                                 <term><varname>systemd.crash_chvt=</varname></term>
1033
1034                                 <listitem><para>Takes an integer
1035                                 argument. If positive systemd
1036                                 activates the specified virtual
1037                                 terminal when it crashes. Defaults to
1038                                 <constant>-1</constant>.</para></listitem>
1039                         </varlistentry>
1040
1041                         <varlistentry>
1042                                 <term><varname>systemd.confirm_spawn=</varname></term>
1043
1044                                 <listitem><para>Takes a boolean
1045                                 argument. If <option>true</option>,
1046                                 asks for confirmation when spawning
1047                                 processes. Defaults to
1048                                 <option>false</option>.</para></listitem>
1049                         </varlistentry>
1050
1051                         <varlistentry>
1052                                 <term><varname>systemd.show_status=</varname></term>
1053
1054                                 <listitem><para>Takes a boolean
1055                                 argument or the constant
1056                                 <constant>auto</constant>. If
1057                                 <option>true</option>, shows terse
1058                                 service status updates on the console
1059                                 during bootup.
1060                                 <constant>auto</constant> behaves like
1061                                 <option>false</option> until a service
1062                                 fails or there is a significant delay
1063                                 in boot. Defaults to
1064                                 <option>true</option>, unless
1065                                 <option>quiet</option> is passed as
1066                                 kernel command line option in which
1067                                 case it defaults to
1068                                 <constant>auto</constant>.</para></listitem>
1069                         </varlistentry>
1070
1071                         <varlistentry>
1072                                 <term><varname>systemd.log_target=</varname></term>
1073                                 <term><varname>systemd.log_level=</varname></term>
1074                                 <term><varname>systemd.log_color=</varname></term>
1075                                 <term><varname>systemd.log_location=</varname></term>
1076
1077                                 <listitem><para>Controls log output,
1078                                 with the same effect as the
1079                                 <varname>$SYSTEMD_LOG_TARGET</varname>, <varname>$SYSTEMD_LOG_LEVEL</varname>, <varname>$SYSTEMD_LOG_COLOR</varname>, <varname>$SYSTEMD_LOG_LOCATION</varname>
1080                                 environment variables described above.</para></listitem>
1081                         </varlistentry>
1082
1083                         <varlistentry>
1084                                 <term><varname>systemd.default_standard_output=</varname></term>
1085                                 <term><varname>systemd.default_standard_error=</varname></term>
1086                                 <listitem><para>Controls default
1087                                 standard output and error output for
1088                                 services, with the same effect as the
1089                                 <option>--default-standard-output=</option>
1090                                 and <option>--default-standard-error=</option>
1091                                 command line arguments described
1092                                 above, respectively.</para></listitem>
1093                         </varlistentry>
1094
1095                         <varlistentry>
1096                                 <term><varname>systemd.setenv=</varname></term>
1097
1098                                 <listitem><para>Takes a string
1099                                 argument in the form VARIABLE=VALUE.
1100                                 May be used to set default environment
1101                                 variables to add to forked child processes.
1102                                 May be used more than once to set multiple
1103                                 variables.</para></listitem>
1104                         </varlistentry>
1105
1106                         <varlistentry>
1107                                 <term><varname>quiet</varname></term>
1108
1109                                 <listitem><para>Turn off
1110                                 status output at boot, much like
1111                                 <varname>systemd.show_status=false</varname>
1112                                 would. Note that this option is also
1113                                 read by the kernel itself and disables
1114                                 kernel log output. Passing this option
1115                                 hence turns off the usual output from
1116                                 both the system manager and the kernel.
1117                                 </para></listitem>
1118                         </varlistentry>
1119
1120                         <varlistentry>
1121                                 <term><varname>debug</varname></term>
1122
1123                                 <listitem><para>Turn on debugging
1124                                 output. This is equivalent to
1125                                 <varname>systemd.log_level=debug</varname>.
1126                                 Note that this option is also read by
1127                                 the kernel itself and enables kernel
1128                                 debug output.  Passing this option
1129                                 hence turns on the debug output from
1130                                 both the system manager and the
1131                                 kernel.</para></listitem>
1132                         </varlistentry>
1133
1134                         <varlistentry>
1135                                 <term><varname>-b</varname></term>
1136                                 <term><varname>emergency</varname></term>
1137
1138                                 <listitem><para>Boot into emergency
1139                                 mode. This is equivalent to
1140                                 <varname>systemd.unit=emergency.target</varname>
1141                                 and provided for compatibility
1142                                 reasons and to be easier to type.</para></listitem>
1143                         </varlistentry>
1144
1145                         <varlistentry>
1146                                 <term><varname>single</varname></term>
1147                                 <term><varname>s</varname></term>
1148                                 <term><varname>S</varname></term>
1149                                 <term><varname>1</varname></term>
1150
1151                                 <listitem><para>Boot into rescue
1152                                 mode. This is equivalent to
1153                                 <varname>systemd.unit=rescue.target</varname>
1154                                 and provided for compatibility reasons
1155                                 and to be easier to
1156                                 type.</para></listitem>
1157                         </varlistentry>
1158
1159                         <varlistentry>
1160                                 <term><varname>2</varname></term>
1161                                 <term><varname>3</varname></term>
1162                                 <term><varname>4</varname></term>
1163                                 <term><varname>5</varname></term>
1164
1165                                 <listitem><para>Boot into the
1166                                 specified legacy SysV runlevel. These
1167                                 are equivalent to
1168                                 <varname>systemd.unit=runlevel2.target</varname>,
1169                                 <varname>systemd.unit=runlevel3.target</varname>,
1170                                 <varname>systemd.unit=runlevel4.target</varname>,
1171                                 and <varname>systemd.unit=runlevel5.target</varname>, respectively,
1172                                 and provided for compatibility reasons
1173                                 and to be easier to
1174                                 type.</para></listitem>
1175                         </varlistentry>
1176
1177                         <varlistentry>
1178                                 <term><varname>locale.LANG=</varname></term>
1179                                 <term><varname>locale.LANGUAGE=</varname></term>
1180                                 <term><varname>locale.LC_CTYPE=</varname></term>
1181                                 <term><varname>locale.LC_NUMERIC=</varname></term>
1182                                 <term><varname>locale.LC_TIME=</varname></term>
1183                                 <term><varname>locale.LC_COLLATE=</varname></term>
1184                                 <term><varname>locale.LC_MONETARY=</varname></term>
1185                                 <term><varname>locale.LC_MESSAGES=</varname></term>
1186                                 <term><varname>locale.LC_PAPER=</varname></term>
1187                                 <term><varname>locale.LC_NAME=</varname></term>
1188                                 <term><varname>locale.LC_ADDRESS=</varname></term>
1189                                 <term><varname>locale.LC_TELEPHONE=</varname></term>
1190                                 <term><varname>locale.LC_MEASUREMENT=</varname></term>
1191                                 <term><varname>locale.LC_IDENTIFICATION=</varname></term>
1192
1193                                 <listitem><para>Set the system locale
1194                                 to use. This overrides the settings in
1195                                 <filename>/etc/locale.conf</filename>. For
1196                                 more information see
1197                                 <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1198                                 and
1199                                 <citerefentry><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
1200                                 </para></listitem>
1201                         </varlistentry>
1202                 </variablelist>
1203
1204                 <para>For other kernel command line parameters
1205                 understood by components of the core OS, please refer
1206                 to
1207                 <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
1208         </refsect1>
1209
1210         <refsect1>
1211                 <title>Sockets and FIFOs</title>
1212
1213                 <variablelist>
1214                         <varlistentry>
1215                                 <term><filename>/run/systemd/notify</filename></term>
1216
1217                                 <listitem><para>Daemon status
1218                                 notification socket. This is an
1219                                 <constant>AF_UNIX</constant> datagram socket and is used to
1220                                 implement the daemon notification
1221                                 logic as implemented by
1222                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
1223
1224                         </varlistentry>
1225
1226                         <varlistentry>
1227                                 <term><filename>/run/systemd/shutdownd</filename></term>
1228
1229                                 <listitem><para>Used internally by the
1230                                 <citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>8</manvolnum></citerefentry>
1231                                 tool to implement delayed
1232                                 shutdowns. This is an <constant>AF_UNIX</constant> datagram
1233                                 socket.</para></listitem>
1234                         </varlistentry>
1235
1236                         <varlistentry>
1237                                 <term><filename>/run/systemd/private</filename></term>
1238
1239                                 <listitem><para>Used internally as
1240                                 communication channel between
1241                                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1242                                 and the systemd process. This is an
1243                                 <constant>AF_UNIX</constant> stream socket. This interface
1244                                 is private to systemd and should not
1245                                 be used in external
1246                                 projects.</para></listitem>
1247                         </varlistentry>
1248
1249                         <varlistentry>
1250                                 <term><filename>/dev/initctl</filename></term>
1251
1252                                 <listitem><para>Limited compatibility
1253                                 support for the SysV client interface,
1254                                 as implemented by the
1255                                 <filename>systemd-initctl.service</filename>
1256                                 unit. This is a named pipe in the file
1257                                 system. This interface is obsolete and
1258                                 should not be used in new
1259                                 applications.</para></listitem>
1260                         </varlistentry>
1261                 </variablelist>
1262         </refsect1>
1263
1264         <refsect1>
1265                 <title>See Also</title>
1266                 <para>
1267                         The <ulink url="http://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>,
1268                         <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1269                         <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1270                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1271                         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1272                         <citerefentry><refentrytitle>systemd-notify</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1273                         <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1274                         <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
1275                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1276                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1277                         <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1278                         <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1279                         <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1280                         <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
1281                 </para>
1282         </refsect1>
1283
1284 </refentry>