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26
27 <refentry id="systemd.unit">
28
29 <refentryinfo>
30 <title>systemd.unit</title>
31 <productname>systemd</productname>
32
33 <authorgroup>
34 <author>
35 <contrib>Developer</contrib>
36 <firstname>Lennart</firstname>
37 <surname>Poettering</surname>
38 <email>lennart@poettering.net</email>
39 </author>
40 </authorgroup>
41 </refentryinfo>
42
43 <refmeta>
44 <refentrytitle>systemd.unit</refentrytitle>
45 <manvolnum>5</manvolnum>
46 </refmeta>
47
48 <refnamediv>
49 <refname>systemd.unit</refname>
50 <refpurpose>Unit configuration</refpurpose>
51 </refnamediv>
52
53 <refsynopsisdiv>
54 <para><filename><replaceable>service</replaceable>.service</filename>,
55 <filename><replaceable>socket</replaceable>.socket</filename>,
56 <filename><replaceable>device</replaceable>.device</filename>,
57 <filename><replaceable>mount</replaceable>.mount</filename>,
58 <filename><replaceable>automount</replaceable>.automount</filename>,
59 <filename><replaceable>swap</replaceable>.swap</filename>,
60 <filename><replaceable>target</replaceable>.target</filename>,
61 <filename><replaceable>path</replaceable>.path</filename>,
62 <filename><replaceable>timer</replaceable>.timer</filename>,
63 <filename><replaceable>snapshot</replaceable>.snapshot</filename>,
64 <filename><replaceable>slice</replaceable>.slice</filename>,
65 <filename><replaceable>scope</replaceable>.scope</filename></para>
66
67 <para><literallayout><filename>/etc/systemd/system/*</filename>
68 <filename>/run/systemd/system/*</filename>
69 <filename>/usr/lib/systemd/system/*</filename>
70 <filename>...</filename>
71 </literallayout></para>
72
73 <para><literallayout><filename>$XDG_CONFIG_HOME/systemd/user/*</filename>
74 <filename>$HOME/.config/systemd/user/*</filename>
75 <filename>/etc/systemd/user/*</filename>
76 <filename>/run/systemd/user/*</filename>
77 <filename>/usr/lib/systemd/user/*</filename>
78 <filename>...</filename>
79 </literallayout></para>
80 </refsynopsisdiv>
81
82 <refsect1>
83 <title>Description</title>
84
85 <para>A unit configuration file encodes information
86 about a service, a socket, a device, a mount point, an
87 automount point, a swap file or partition, a start-up
88 target, a watched file system path, a timer controlled
89 and supervised by
90 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
91 a temporary system state snapshot, a resource
92 management slice or a group of externally created
93 processes. The syntax is inspired by <ulink
94 url="http://standards.freedesktop.org/desktop-entry-spec/latest/">XDG
95 Desktop Entry Specification</ulink>
96 <filename>.desktop</filename> files, which are in turn
97 inspired by Microsoft Windows
98 <filename>.ini</filename> files.</para>
99
100 <para>This man page lists the common configuration
101 options of all the unit types. These options need to
102 be configured in the [Unit] or [Install]
103 sections of the unit files.</para>
104
105 <para>In addition to the generic [Unit] and [Install]
106 sections described here, each unit may have a
107 type-specific section, e.g. [Service] for a service
108 unit. See the respective man pages for more
109 information:
110 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
111 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
112 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
113 <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
114 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
115 <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
116 <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
117 <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
118 <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
119 <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
120 <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
121 <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
122 </para>
123
124 <para>Various settings are allowed to be specified
125 more than once, in which case the interpretation
126 depends on the setting. Often, multiple settings form
127 a list, and setting to an empty value "resets", which
128 means that previous assignments are ignored. When this
129 is allowed, it is mentioned in the description of the
130 setting. Note that using multiple assignments to the
131 same value makes the unit file incompatible with
132 parsers for the XDG <filename>.desktop</filename> file
133 format.</para>
134
135 <para>Unit files are loaded from a set of paths
136 determined during compilation, described in the next section.
137 </para>
138
139 <para>Unit files may contain additional options on top
140 of those listed here. If systemd encounters an unknown
141 option, it will write a warning log message but
142 continue loading the unit. If an option is prefixed
143 with <option>X-</option>, it is ignored completely by
144 systemd. Applications may use this to include
145 additional information in the unit files.</para>
146
147 <para>Boolean arguments used in unit files can be
148 written in various formats. For positive settings the
149 strings <option>1</option>, <option>yes</option>,
150 <option>true</option> and <option>on</option> are
151 equivalent. For negative settings, the strings
152 <option>0</option>, <option>no</option>,
153 <option>false</option> and <option>off</option> are
154 equivalent.</para>
155
156 <para>Time span values encoded in unit files can be
157 written in various formats. A stand-alone number
158 specifies a time in seconds. If suffixed with a time
159 unit, the unit is honored. A concatenation of multiple
160 values with units is supported, in which case the
161 values are added up. Example: "50" refers to 50
162 seconds; "2min 200ms" refers to 2 minutes plus 200
163 milliseconds, i.e. 120200ms. The following time units
164 are understood: s, min, h, d, w, ms, us. For details
165 see
166 <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
167
168 <para>Empty lines and lines starting with # or ; are
169 ignored. This may be used for commenting. Lines ending
170 in a backslash are concatenated with the following
171 line while reading and the backslash is replaced by a
172 space character. This may be used to wrap long lines.</para>
173
174 <para>Along with a unit file
175 <filename>foo.service</filename>, the directory
176 <filename>foo.service.wants/</filename> may exist. All
177 unit files symlinked from such a directory are
178 implicitly added as dependencies of type
179 <varname>Wanted=</varname> to the unit. This is useful
180 to hook units into the start-up of other units,
181 without having to modify their unit files. For details
182 about the semantics of <varname>Wanted=</varname>, see
183 below. The preferred way to create symlinks in the
184 <filename>.wants/</filename> directory of a unit file
185 is with the <command>enable</command> command of the
186 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
187 tool which reads information from the [Install]
188 section of unit files (see below). A similar
189 functionality exists for <varname>Requires=</varname>
190 type dependencies as well, the directory suffix is
191 <filename>.requires/</filename> in this case.</para>
192
193 <para>Along with a unit file
194 <filename>foo.service</filename>, a directory
195 <filename>foo.service.d/</filename> may exist. All
196 files with the suffix <literal>.conf</literal> from
197 this directory will be parsed after the file itself is
198 parsed. This is useful to alter or add configuration
199 settings to a unit, without having to modify their
200 unit files. Make sure that the file that is included
201 has the appropriate section headers before any
202 directive.</para>
203
204 <para>Note that while systemd offers a flexible
205 dependency system between units it is recommended to
206 use this functionality only sparingly and instead rely
207 on techniques such as bus-based or socket-based
208 activation which make dependencies implicit, resulting
209 in a both simpler and more flexible system.</para>
210
211 <para>Some unit names reflect paths existing in the
212 file system namespace. Example: a device unit
213 <filename>dev-sda.device</filename> refers to a device
214 with the device node <filename noindex='true'>/dev/sda</filename> in
215 the file system namespace. If this applies, a special
216 way to escape the path name is used, so that the
217 result is usable as part of a filename. Basically,
218 given a path, "/" is replaced by "-", and all
219 unprintable characters and the "-" are replaced by
220 C-style "\x20" escapes. The root directory "/" is
221 encoded as single dash, while otherwise the initial
222 and ending "/" is removed from all paths during
223 transformation. This escaping is reversible.</para>
224
225 <para>Optionally, units may be instantiated from a
226 template file at runtime. This allows creation of
227 multiple units from a single configuration file. If
228 systemd looks for a unit configuration file, it will
229 first search for the literal unit name in the
230 file system. If that yields no success and the unit
231 name contains an <literal>@</literal> character, systemd will look for a
232 unit template that shares the same name but with the
233 instance string (i.e. the part between the <literal>@</literal> character
234 and the suffix) removed. Example: if a service
235 <filename>getty@tty3.service</filename> is requested
236 and no file by that name is found, systemd will look
237 for <filename>getty@.service</filename> and
238 instantiate a service from that configuration file if
239 it is found.</para>
240
241 <para>To refer to the instance string from
242 within the configuration file you may use the special
243 <literal>%i</literal> specifier in many of the
244 configuration options. See below for details.</para>
245
246 <para>If a unit file is empty (i.e. has the file size
247 0) or is symlinked to <filename>/dev/null</filename>,
248 its configuration will not be loaded and it appears
249 with a load state of <literal>masked</literal>, and
250 cannot be activated. Use this as an effective way to
251 fully disable a unit, making it impossible to start it
252 even manually.</para>
253
254 <para>The unit file format is covered by the
255 <ulink
256 url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
257 Stability Promise</ulink>.</para>
258
259 </refsect1>
260
261 <refsect1>
262 <title>Unit Load Path</title>
263
264 <para>Unit files are loaded from a set of paths
265 determined during compilation, described in the two
266 tables below. Unit files found in directories listed
267 earlier override files with the same name in
268 directories lower in the list.</para>
269
270 <para>When systemd is running in user mode
271 (<option>--user</option>) and the variable
272 <varname>$SYSTEMD_UNIT_PATH</varname> is set, this
273 contents of this variable overrides the unit load
274 path.
275 </para>
276
277 <table>
278 <title>
279 Load path when running in system mode (<option>--system</option>).
280 </title>
281
282 <tgroup cols='2'>
283 <colspec colname='path' />
284 <colspec colname='expl' />
285 <thead>
286 <row>
287 <entry>Path</entry>
288 <entry>Description</entry>
289 </row>
290 </thead>
291 <tbody>
292 <row>
293 <entry><filename>/etc/systemd/system</filename></entry>
294 <entry>Local configuration</entry>
295 </row>
296 <row>
297 <entry><filename>/run/systemd/system</filename></entry>
298 <entry>Runtime units</entry>
299 </row>
300 <row>
301 <entry><filename>/usr/lib/systemd/system</filename></entry>
302 <entry>Units of installed packages</entry>
303 </row>
304 </tbody>
305 </tgroup>
306 </table>
307
308 <table>
309 <title>
310 Load path when running in user mode (<option>--user</option>).
311 </title>
312
313 <tgroup cols='2'>
314 <colspec colname='path' />
315 <colspec colname='expl' />
316 <thead>
317 <row>
318 <entry>Path</entry>
319 <entry>Description</entry>
320 </row>
321 </thead>
322 <tbody>
323 <row>
324 <entry><filename>$XDG_CONFIG_HOME/systemd/user</filename></entry>
325 <entry>User configuration (only used when $XDG_CONFIG_HOME is set)</entry>
326 </row>
327 <row>
328 <entry><filename>$HOME/.config/systemd/user</filename></entry>
329 <entry>User configuration (only used when $XDG_CONFIG_HOME is not set)</entry>
330 </row>
331 <row>
332 <entry><filename>/etc/systemd/user</filename></entry>
333 <entry>Local configuration</entry>
334 </row>
335 <row>
336 <entry><filename>/run/systemd/user</filename></entry>
337 <entry>Runtime units</entry>
338 </row>
339 <row>
340 <entry><filename>/usr/lib/systemd/user</filename></entry>
341 <entry>Units of installed packages</entry>
342 </row>
343 </tbody>
344 </tgroup>
345 </table>
346
347 <para>Additional units might be loaded into systemd
348 ("linked") from directories not on the unit load
349 path. See the <command>link</command> command for
350 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Also,
351 some units are dynamically created via generators
352 <ulink
353 url="http://www.freedesktop.org/wiki/Software/systemd/Generators/">Generators</ulink>.
354 </para>
355 </refsect1>
356
357 <refsect1>
358 <title>[Unit] Section Options</title>
359
360 <para>Unit file may include a [Unit] section, which
361 carries generic information about the unit that is not
362 dependent on the type of unit:</para>
363
364 <variablelist class='unit-directives'>
365
366 <varlistentry>
367 <term><varname>Description=</varname></term>
368 <listitem><para>A free-form string
369 describing the unit. This is intended
370 for use in UIs to show descriptive
371 information along with the unit
372 name. The description should contain a name
373 that means something to the end user.
374 <literal>Apache2 Web Server</literal> is a good
375 example. Bad examples are
376 <literal>high-performance light-weight HTTP
377 server</literal> (too generic) or
378 <literal>Apache2</literal> (too specific and
379 meaningless for people who do not know
380 Apache).</para></listitem>
381 </varlistentry>
382
383 <varlistentry>
384 <term><varname>Documentation=</varname></term>
385 <listitem><para>A space-separated list
386 of URIs referencing documentation for
387 this unit or its
388 configuration. Accepted are only URIs
389 of the types
390 <literal>http://</literal>,
391 <literal>https://</literal>,
392 <literal>file:</literal>,
393 <literal>info:</literal>,
394 <literal>man:</literal>. For more
395 information about the syntax of these
396 URIs, see
397 <citerefentry><refentrytitle>uri</refentrytitle><manvolnum>7</manvolnum></citerefentry>. The
398 URIs should be listed in order of
399 relevance, starting with the most
400 relevant. It is a good idea to first
401 reference documentation that explains
402 what the unit's purpose is, followed
403 by how it is configured, followed by
404 any other related documentation. This
405 option may be specified more than once,
406 in which case the specified list of
407 URIs is merged. If the empty string is
408 assigned to this option, the list is
409 reset and all prior assignments will
410 have no effect.</para></listitem>
411 </varlistentry>
412
413 <varlistentry>
414 <term><varname>Requires=</varname></term>
415
416 <listitem><para>Configures requirement
417 dependencies on other units. If this
418 unit gets activated, the units listed
419 here will be activated as well. If one
420 of the other units gets deactivated or
421 its activation fails, this unit will
422 be deactivated. This option may be
423 specified more than once or multiple
424 space-separated units may be specified
425 in one option in which case
426 requirement dependencies for all
427 listed names will be created. Note
428 that requirement dependencies do not
429 influence the order in which services
430 are started or stopped. This has to be
431 configured independently with the
432 <varname>After=</varname> or
433 <varname>Before=</varname> options. If
434 a unit
435 <filename>foo.service</filename>
436 requires a unit
437 <filename>bar.service</filename> as
438 configured with
439 <varname>Requires=</varname> and no
440 ordering is configured with
441 <varname>After=</varname> or
442 <varname>Before=</varname>, then both
443 units will be started simultaneously
444 and without any delay between them if
445 <filename>foo.service</filename> is
446 activated. Often it is a better choice
447 to use <varname>Wants=</varname>
448 instead of
449 <varname>Requires=</varname> in order
450 to achieve a system that is more
451 robust when dealing with failing
452 services.</para>
453
454 <para>Note that dependencies of this
455 type may also be configured outside of
456 the unit configuration file by
457 adding a symlink to a
458 <filename>.requires/</filename> directory
459 accompanying the unit file. For
460 details see above.</para></listitem>
461 </varlistentry>
462
463 <varlistentry>
464 <term><varname>RequiresOverridable=</varname></term>
465
466 <listitem><para>Similar to
467 <varname>Requires=</varname>.
468 Dependencies listed in
469 <varname>RequiresOverridable=</varname>
470 which cannot be fulfilled or fail to
471 start are ignored if the startup was
472 explicitly requested by the user. If
473 the start-up was pulled in indirectly
474 by some dependency or automatic
475 start-up of units that is not
476 requested by the user, this dependency
477 must be fulfilled and otherwise the
478 transaction fails. Hence, this option
479 may be used to configure dependencies
480 that are normally honored unless the
481 user explicitly starts up the unit, in
482 which case whether they failed or not
483 is irrelevant.</para></listitem>
484
485 </varlistentry>
486 <varlistentry>
487 <term><varname>Requisite=</varname></term>
488 <term><varname>RequisiteOverridable=</varname></term>
489
490 <listitem><para>Similar to
491 <varname>Requires=</varname> and
492 <varname>RequiresOverridable=</varname>,
493 respectively. However, if the units
494 listed here are not started already,
495 they will not be started and the
496 transaction will fail immediately.
497 </para></listitem>
498 </varlistentry>
499
500 <varlistentry>
501 <term><varname>Wants=</varname></term>
502
503 <listitem><para>A weaker version of
504 <varname>Requires=</varname>. Units
505 listed in this option will be started
506 if the configuring unit is. However,
507 if the listed units fail to start
508 or cannot be added to the transaction,
509 this has no impact on the validity of
510 the transaction as a whole. This is
511 the recommended way to hook start-up
512 of one unit to the start-up of another
513 unit.</para>
514
515 <para>Note that dependencies of this
516 type may also be configured outside of
517 the unit configuration file by adding
518 symlinks to a
519 <filename>.wants/</filename> directory
520 accompanying the unit file. For
521 details, see above.</para></listitem>
522 </varlistentry>
523
524 <varlistentry>
525 <term><varname>BindsTo=</varname></term>
526
527 <listitem><para>Configures requirement
528 dependencies, very similar in style to
529 <varname>Requires=</varname>, however
530 in addition to this behavior, it also
531 declares that this unit is stopped
532 when any of the units listed suddenly
533 disappears. Units can suddenly,
534 unexpectedly disappear if a service
535 terminates on its own choice, a device
536 is unplugged or a mount point
537 unmounted without involvement of
538 systemd.</para></listitem>
539 </varlistentry>
540
541 <varlistentry>
542 <term><varname>PartOf=</varname></term>
543
544 <listitem><para>Configures dependencies
545 similar to <varname>Requires=</varname>,
546 but limited to stopping and restarting
547 of units. When systemd stops or restarts
548 the units listed here, the action is
549 propagated to this unit.
550 Note that this is a one-way dependency —
551 changes to this unit do not affect the
552 listed units.
553 </para></listitem>
554 </varlistentry>
555
556 <varlistentry>
557 <term><varname>Conflicts=</varname></term>
558
559 <listitem><para>A space-separated list
560 of unit names. Configures negative
561 requirement dependencies. If a unit
562 has a <varname>Conflicts=</varname>
563 setting on another unit, starting the
564 former will stop the latter and vice
565 versa. Note that this setting is
566 independent of and orthogonal to the
567 <varname>After=</varname> and
568 <varname>Before=</varname> ordering
569 dependencies.</para>
570
571 <para>If a unit A that conflicts with
572 a unit B is scheduled to be started at
573 the same time as B, the transaction
574 will either fail (in case both are
575 required part of the transaction) or
576 be modified to be fixed (in case one
577 or both jobs are not a required part
578 of the transaction). In the latter
579 case, the job that is not the required
580 will be removed, or in case both are
581 not required, the unit that conflicts
582 will be started and the unit that is
583 conflicted is
584 stopped.</para></listitem>
585 </varlistentry>
586
587 <varlistentry>
588 <term><varname>Before=</varname></term>
589 <term><varname>After=</varname></term>
590
591 <listitem><para>A space-separated list
592 of unit names. Configures ordering
593 dependencies between units. If a unit
594 <filename>foo.service</filename>
595 contains a setting
596 <option>Before=bar.service</option>
597 and both units are being started,
598 <filename>bar.service</filename>'s
599 start-up is delayed until
600 <filename>foo.service</filename> is
601 started up. Note that this setting is
602 independent of and orthogonal to the
603 requirement dependencies as configured
604 by <varname>Requires=</varname>. It is
605 a common pattern to include a unit
606 name in both the
607 <varname>After=</varname> and
608 <varname>Requires=</varname> option, in
609 which case the unit listed will be
610 started before the unit that is
611 configured with these options. This
612 option may be specified more than
613 once, in which case ordering
614 dependencies for all listed names are
615 created. <varname>After=</varname> is
616 the inverse of
617 <varname>Before=</varname>, i.e. while
618 <varname>After=</varname> ensures that
619 the configured unit is started after
620 the listed unit finished starting up,
621 <varname>Before=</varname> ensures the
622 opposite, i.e. that the configured
623 unit is fully started up before the
624 listed unit is started. Note that when
625 two units with an ordering dependency
626 between them are shut down, the
627 inverse of the start-up order is
628 applied. i.e. if a unit is configured
629 with <varname>After=</varname> on
630 another unit, the former is stopped
631 before the latter if both are shut
632 down. If one unit with an ordering
633 dependency on another unit is shut
634 down while the latter is started up,
635 the shut down is ordered before the
636 start-up regardless of whether the
637 ordering dependency is actually of
638 type <varname>After=</varname> or
639 <varname>Before=</varname>. If two
640 units have no ordering dependencies
641 between them, they are shut down or
642 started up simultaneously, and no
643 ordering takes
644 place. </para></listitem>
645 </varlistentry>
646
647 <varlistentry>
648 <term><varname>OnFailure=</varname></term>
649
650 <listitem><para>A space-separated list
651 of one or more units that are
652 activated when this unit enters the
653 <literal>failed</literal>
654 state.</para></listitem>
655 </varlistentry>
656
657 <varlistentry>
658 <term><varname>PropagatesReloadTo=</varname></term>
659 <term><varname>ReloadPropagatedFrom=</varname></term>
660
661 <listitem><para>A space-separated list
662 of one or more units where reload
663 requests on this unit will be
664 propagated to, or reload requests on
665 the other unit will be propagated to
666 this unit, respectively. Issuing a
667 reload request on a unit will
668 automatically also enqueue a reload
669 request on all units that the reload
670 request shall be propagated to via
671 these two settings.</para></listitem>
672 </varlistentry>
673
674 <varlistentry>
675 <term><varname>JoinsNamespaceOf=</varname></term>
676
677 <listitem><para>For units that start
678 processes (such as service units),
679 lists one or more other units whose
680 network and/or temporary file
681 namespace to join. This only applies
682 to unit types which support the
683 <varname>PrivateNetwork=</varname> and
684 <varname>PrivateTmp=</varname>
685 directives (see
686 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
687 for details). If a unit that has this
688 setting set is started, its processes
689 will see the same
690 <filename>/tmp</filename>,
691 <filename>/tmp/var</filename> and
692 network namespace as one listed unit
693 that is started. If multiple listed
694 units are already started, it is not
695 defined which namespace is
696 joined. Note that this setting only
697 has an effect if
698 <varname>PrivateNetwork=</varname>
699 and/or <varname>PrivateTmp=</varname>
700 is enabled for both the unit that
701 joins the namespace and the unit whose
702 namespace is joined.</para></listitem>
703 </varlistentry>
704
705 <varlistentry>
706 <term><varname>RequiresMountsFor=</varname></term>
707
708 <listitem><para>Takes a
709 space-separated list of absolute
710 paths. Automatically adds dependencies
711 of type <varname>Requires=</varname>
712 and <varname>After=</varname> for all
713 mount units required to access the
714 specified path.</para>
715
716 <para>Mount points marked with
717 <option>noauto</option> are not
718 mounted automatically and will be
719 ignored for the purposes of this
720 option. If such a mount should be a
721 requirement for this unit,
722 direct dependencies on the mount
723 units may be added
724 (<varname>Requires=</varname> and
725 <varname>After=</varname> or
726 some other combination).
727 </para></listitem>
728 </varlistentry>
729
730 <varlistentry>
731 <term><varname>OnFailureJobMode=</varname></term>
732
733 <listitem><para>Takes a value of
734 <literal>fail</literal>,
735 <literal>replace</literal>,
736 <literal>replace-irreversibly</literal>,
737 <literal>isolate</literal>,
738 <literal>flush</literal>,
739 <literal>ignore-dependencies</literal>
740 or
741 <literal>ignore-requirements</literal>. Defaults
742 to
743 <literal>replace</literal>. Specifies
744 how the units listed in
745 <varname>OnFailure=</varname> will be
746 enqueued. See
747 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
748 <option>--job-mode=</option> option
749 for details on the possible values. If
750 this is set to
751 <literal>isolate</literal>, only a
752 single unit may be listed in
753 <varname>OnFailure=</varname>..</para></listitem>
754 </varlistentry>
755
756 <varlistentry>
757 <term><varname>IgnoreOnIsolate=</varname></term>
758
759 <listitem><para>Takes a boolean
760 argument. If <option>true</option>,
761 this unit will not be stopped when
762 isolating another unit. Defaults to
763 <option>false</option>.</para></listitem>
764 </varlistentry>
765
766 <varlistentry>
767 <term><varname>IgnoreOnSnapshot=</varname></term>
768
769 <listitem><para>Takes a boolean
770 argument. If <option>true</option>,
771 this unit will not be included in
772 snapshots. Defaults to
773 <option>true</option> for device and
774 snapshot units, <option>false</option>
775 for the others.</para></listitem>
776 </varlistentry>
777
778 <varlistentry>
779 <term><varname>StopWhenUnneeded=</varname></term>
780
781 <listitem><para>Takes a boolean
782 argument. If <option>true</option>,
783 this unit will be stopped when it is
784 no longer used. Note that in order to
785 minimize the work to be executed,
786 systemd will not stop units by default
787 unless they are conflicting with other
788 units, or the user explicitly
789 requested their shut down. If this
790 option is set, a unit will be
791 automatically cleaned up if no other
792 active unit requires it. Defaults to
793 <option>false</option>.</para></listitem>
794 </varlistentry>
795
796 <varlistentry>
797 <term><varname>RefuseManualStart=</varname></term>
798 <term><varname>RefuseManualStop=</varname></term>
799
800 <listitem><para>Takes a boolean
801 argument. If <option>true</option>,
802 this unit can only be activated
803 or deactivated indirectly. In
804 this case, explicit start-up
805 or termination requested by the
806 user is denied, however if it is
807 started or stopped as a
808 dependency of another unit, start-up
809 or termination will succeed. This
810 is mostly a safety feature to ensure
811 that the user does not accidentally
812 activate units that are not intended
813 to be activated explicitly, and not
814 accidentally deactivate units that are
815 not intended to be deactivated.
816 These options default to
817 <option>false</option>.</para></listitem>
818 </varlistentry>
819
820 <varlistentry>
821 <term><varname>AllowIsolate=</varname></term>
822
823 <listitem><para>Takes a boolean
824 argument. If <option>true</option>,
825 this unit may be used with the
826 <command>systemctl isolate</command>
827 command. Otherwise, this will be
828 refused. It probably is a good idea to
829 leave this disabled except for target
830 units that shall be used similar to
831 runlevels in SysV init systems, just
832 as a precaution to avoid unusable
833 system states. This option defaults to
834 <option>false</option>.</para></listitem>
835 </varlistentry>
836
837 <varlistentry>
838 <term><varname>DefaultDependencies=</varname></term>
839
840 <listitem><para>Takes a boolean
841 argument. If <option>true</option>,
842 (the default), a few default
843 dependencies will implicitly be
844 created for the unit. The actual
845 dependencies created depend on the
846 unit type. For example, for service
847 units, these dependencies ensure that
848 the service is started only after
849 basic system initialization is
850 completed and is properly terminated on
851 system shutdown. See the respective
852 man pages for details. Generally, only
853 services involved with early boot or
854 late shutdown should set this option
855 to <option>false</option>. It is
856 highly recommended to leave this
857 option enabled for the majority of
858 common units. If set to
859 <option>false</option>, this option
860 does not disable all implicit
861 dependencies, just non-essential
862 ones.</para></listitem>
863 </varlistentry>
864
865 <varlistentry>
866 <term><varname>JobTimeoutSec=</varname></term>
867
868 <listitem><para>When clients are
869 waiting for a job of this unit to
870 complete, time out after the specified
871 time. If this time limit is reached,
872 the job will be cancelled, the unit
873 however will not change state or even
874 enter the <literal>failed</literal>
875 mode. This value defaults to 0 (job
876 timeouts disabled), except for device
877 units. NB: this timeout is independent
878 from any unit-specific timeout (for
879 example, the timeout set with
880 <varname>Timeout=</varname> in service
881 units) as the job timeout has no
882 effect on the unit itself, only on the
883 job that might be pending for it. Or
884 in other words: unit-specific timeouts
885 are useful to abort unit state
886 changes, and revert them. The job
887 timeout set with this option however
888 is useful to abort only the job
889 waiting for the unit state to
890 change.</para></listitem>
891 </varlistentry>
892
893 <varlistentry>
894 <term><varname>ConditionArchitecture=</varname></term>
895 <term><varname>ConditionVirtualization=</varname></term>
896 <term><varname>ConditionHost=</varname></term>
897 <term><varname>ConditionKernelCommandLine=</varname></term>
898 <term><varname>ConditionSecurity=</varname></term>
899 <term><varname>ConditionCapability=</varname></term>
900 <term><varname>ConditionACPower=</varname></term>
901 <term><varname>ConditionPathExists=</varname></term>
902 <term><varname>ConditionPathExistsGlob=</varname></term>
903 <term><varname>ConditionPathIsDirectory=</varname></term>
904 <term><varname>ConditionPathIsSymbolicLink=</varname></term>
905 <term><varname>ConditionPathIsMountPoint=</varname></term>
906 <term><varname>ConditionPathIsReadWrite=</varname></term>
907 <term><varname>ConditionDirectoryNotEmpty=</varname></term>
908 <term><varname>ConditionFileNotEmpty=</varname></term>
909 <term><varname>ConditionFileIsExecutable=</varname></term>
910 <term><varname>ConditionNull=</varname></term>
911
912 <listitem><para>Before starting a unit
913 verify that the specified condition is
914 true. If it is not true, the starting
915 of the unit will be skipped, however
916 all ordering dependencies of it are
917 still respected. A failing condition
918 will not result in the unit being
919 moved into a failure state. The
920 condition is checked at the time the
921 queued start job is to be
922 executed.</para>
923
924 <para><varname>ConditionArchitecture=</varname>
925 may be used to check whether the
926 system is running on a specific
927 architecture. Takes one of
928 <varname>x86</varname>,
929 <varname>x86-64</varname>,
930 <varname>ppc</varname>,
931 <varname>ppc64</varname>,
932 <varname>ia64</varname>,
933 <varname>parisc</varname>,
934 <varname>parisc64</varname>,
935 <varname>s390</varname>,
936 <varname>s390x</varname>,
937 <varname>sparc</varname>,
938 <varname>sparc64</varname>,
939 <varname>mips</varname>,
940 <varname>mips64</varname>,
941 <varname>alpha</varname>,
942 <varname>arm</varname>,
943 <varname>arm-be</varname>,
944 <varname>arm64</varname>,
945 <varname>arm64-be</varname>,
946 <varname>sh</varname>,
947 <varname>sh64</varname>,
948 <varname>m86k</varname> to test
949 against a specific architecture. The
950 architecture is determined from the
951 information returned by
952 <citerefentry><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry>
953 and is thus subject to
954 <citerefentry><refentrytitle>personality</refentrytitle><manvolnum>2</manvolnum></citerefentry>. Note
955 that a <varname>Personality=</varname>
956 setting in the same unit file has no
957 effect on this condition. A special
958 architecture name
959 <varname>native</varname> is mapped to
960 the architecture the system manager
961 itself is compiled for. The test may
962 be negated by prepending an
963 exclamation mark.</para>
964
965 <para><varname>ConditionVirtualization=</varname>
966 may be used to check whether the
967 system is executed in a virtualized
968 environment and optionally test
969 whether it is a specific
970 implementation. Takes either boolean
971 value to check if being executed in
972 any virtualized environment, or one of
973 <varname>vm</varname> and
974 <varname>container</varname> to test
975 against a generic type of
976 virtualization solution, or one of
977 <varname>qemu</varname>,
978 <varname>kvm</varname>,
979 <varname>vmware</varname>,
980 <varname>microsoft</varname>,
981 <varname>oracle</varname>,
982 <varname>xen</varname>,
983 <varname>bochs</varname>,
984 <varname>chroot</varname>,
985 <varname>uml</varname>,
986 <varname>openvz</varname>,
987 <varname>lxc</varname>,
988 <varname>lxc-libvirt</varname>,
989 <varname>systemd-nspawn</varname> to
990 test against a specific
991 implementation. If multiple
992 virtualization technologies are nested,
993 only the innermost is considered. The
994 test may be negated by prepending an
995 exclamation mark.</para>
996
997 <para><varname>ConditionHost=</varname>
998 may be used to match against the
999 hostname or machine ID of the
1000 host. This either takes a hostname
1001 string (optionally with shell style
1002 globs) which is tested against the
1003 locally set hostname as returned by
1004 <citerefentry><refentrytitle>gethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
1005 or a machine ID formatted as string
1006 (see
1007 <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
1008 The test may be negated by prepending
1009 an exclamation mark.</para>
1010
1011 <para><varname>ConditionKernelCommandLine=</varname>
1012 may be used to check whether a
1013 specific kernel command line option is
1014 set (or if prefixed with the
1015 exclamation mark unset). The argument
1016 must either be a single word, or an
1017 assignment (i.e. two words, separated
1018 <literal>=</literal>). In the former
1019 case the kernel command line is
1020 searched for the word appearing as is,
1021 or as left hand side of an
1022 assignment. In the latter case the
1023 exact assignment is looked for with
1024 right and left hand side
1025 matching.</para>
1026
1027 <para><varname>ConditionSecurity=</varname>
1028 may be used to check whether the given
1029 security module is enabled on the
1030 system. Currently the recognized values
1031 values are <varname>selinux</varname>,
1032 <varname>apparmor</varname>,
1033 <varname>ima</varname> and
1034 <varname>smack</varname>.
1035 The test may be negated by prepending
1036 an exclamation
1037 mark.</para>
1038
1039 <para><varname>ConditionCapability=</varname>
1040 may be used to check whether the given
1041 capability exists in the capability
1042 bounding set of the service manager
1043 (i.e. this does not check whether
1044 capability is actually available in
1045 the permitted or effective sets, see
1046 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
1047 for details). Pass a capability name
1048 such as <literal>CAP_MKNOD</literal>,
1049 possibly prefixed with an exclamation
1050 mark to negate the check.</para>
1051
1052 <para><varname>ConditionACPower=</varname>
1053 may be used to check whether the
1054 system has AC power, or is exclusively
1055 battery powered at the time of
1056 activation of the unit. This takes a
1057 boolean argument. If set to
1058 <varname>true</varname>, the condition
1059 will hold only if at least one AC
1060 connector of the system is connected
1061 to a power source, or if no AC
1062 connectors are known. Conversely, if
1063 set to <varname>false</varname>, the
1064 condition will hold only if there is
1065 at least one AC connector known and
1066 all AC connectors are disconnected
1067 from a power source.</para>
1068
1069 <para>With
1070 <varname>ConditionPathExists=</varname>
1071 a file existence condition is
1072 checked before a unit is started. If
1073 the specified absolute path name does
1074 not exist, the condition will
1075 fail. If the absolute path name passed
1076 to
1077 <varname>ConditionPathExists=</varname>
1078 is prefixed with an exclamation mark
1079 (<literal>!</literal>), the test is negated, and the unit
1080 is only started if the path does not
1081 exist.</para>
1082
1083 <para><varname>ConditionPathExistsGlob=</varname>
1084 is similar to
1085 <varname>ConditionPathExists=</varname>,
1086 but checks for the existence of at
1087 least one file or directory matching
1088 the specified globbing pattern.</para>
1089
1090 <para><varname>ConditionPathIsDirectory=</varname>
1091 is similar to
1092 <varname>ConditionPathExists=</varname>
1093 but verifies whether a certain path
1094 exists and is a
1095 directory.</para>
1096
1097 <para><varname>ConditionPathIsSymbolicLink=</varname>
1098 is similar to
1099 <varname>ConditionPathExists=</varname>
1100 but verifies whether a certain path
1101 exists and is a symbolic
1102 link.</para>
1103
1104 <para><varname>ConditionPathIsMountPoint=</varname>
1105 is similar to
1106 <varname>ConditionPathExists=</varname>
1107 but verifies whether a certain path
1108 exists and is a mount
1109 point.</para>
1110
1111 <para><varname>ConditionPathIsReadWrite=</varname>
1112 is similar to
1113 <varname>ConditionPathExists=</varname>
1114 but verifies whether the underlying
1115 file system is readable and writable
1116 (i.e. not mounted
1117 read-only).</para>
1118
1119 <para><varname>ConditionDirectoryNotEmpty=</varname>
1120 is similar to
1121 <varname>ConditionPathExists=</varname>
1122 but verifies whether a certain path
1123 exists and is a non-empty
1124 directory.</para>
1125
1126 <para><varname>ConditionFileNotEmpty=</varname>
1127 is similar to
1128 <varname>ConditionPathExists=</varname>
1129 but verifies whether a certain path
1130 exists and refers to a regular file
1131 with a non-zero size.</para>
1132
1133 <para><varname>ConditionFileIsExecutable=</varname>
1134 is similar to
1135 <varname>ConditionPathExists=</varname>
1136 but verifies whether a certain path
1137 exists, is a regular file and marked
1138 executable.</para>
1139
1140 <para>Finally,
1141 <varname>ConditionNull=</varname> may
1142 be used to add a constant condition
1143 check value to the unit. It takes a
1144 boolean argument. If set to
1145 <varname>false</varname>, the condition
1146 will always fail, otherwise
1147 succeed.</para>
1148
1149 <para>If multiple conditions are
1150 specified, the unit will be executed if
1151 all of them apply (i.e. a logical AND
1152 is applied). Condition checks can be
1153 prefixed with a pipe symbol (|) in
1154 which case a condition becomes a
1155 triggering condition. If at least one
1156 triggering condition is defined for a
1157 unit, then the unit will be executed if
1158 at least one of the triggering
1159 conditions apply and all of the
1160 non-triggering conditions. If you
1161 prefix an argument with the pipe
1162 symbol and an exclamation mark, the
1163 pipe symbol must be passed first, the
1164 exclamation second. Except for
1165 <varname>ConditionPathIsSymbolicLink=</varname>,
1166 all path checks follow symlinks. If
1167 any of these options is assigned the
1168 empty string, the list of conditions is
1169 reset completely, all previous
1170 condition settings (of any kind) will
1171 have no effect.</para></listitem>
1172 </varlistentry>
1173
1174 <varlistentry>
1175 <term><varname>SourcePath=</varname></term>
1176 <listitem><para>A path to a
1177 configuration file this unit has been
1178 generated from. This is primarily
1179 useful for implementation of generator
1180 tools that convert configuration from
1181 an external configuration file format
1182 into native unit files. Thus
1183 functionality should not be used in
1184 normal units.</para></listitem>
1185 </varlistentry>
1186 </variablelist>
1187
1188 </refsect1>
1189
1190 <refsect1>
1191 <title>[Install] Section Options</title>
1192
1193 <para>Unit file may include a [Install] section, which
1194 carries installation information for the unit. This
1195 section is not interpreted by
1196 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1197 during runtime. It is used exclusively by the
1198 <command>enable</command> and
1199 <command>disable</command> commands of the
1200 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1201 tool during installation of a unit:</para>
1202
1203 <variablelist class='unit-directives'>
1204 <varlistentry>
1205 <term><varname>Alias=</varname></term>
1206
1207 <listitem><para>A space-seperated list
1208 of additional names this unit shall be
1209 installed under. The names listed here
1210 must have the same suffix (i.e. type)
1211 as the unit file name. This option may
1212 be specified more than once, in which
1213 case all listed names are used. At
1214 installation time, <command>systemctl
1215 enable</command> will create symlinks
1216 from these names to the unit
1217 filename.</para></listitem>
1218 </varlistentry>
1219
1220 <varlistentry>
1221 <term><varname>WantedBy=</varname></term>
1222 <term><varname>RequiredBy=</varname></term>
1223
1224 <listitem><para>This option may be
1225 used more than once, or a
1226 space-separated list of unit names may
1227 be given. A symbolic link is created
1228 in the <filename>.wants/</filename> or
1229 <filename>.requires/</filename>
1230 directory of each of the listed units
1231 when this unit is installed by
1232 <command>systemctl enable</command>.
1233 This has the effect that a dependency
1234 of type <varname>Wants=</varname> or
1235 <varname>Requires=</varname> is added
1236 from the listed unit to the current
1237 unit. The primary result is that the
1238 current unit will be started when the
1239 listed unit is started. See the
1240 description of
1241 <varname>Wants=</varname> and
1242 <varname>Requires=</varname> in the
1243 [Unit] section for details.</para>
1244
1245 <para><command>WantedBy=foo.service</command>
1246 in a service
1247 <filename>bar.service</filename> is
1248 mostly equivalent to
1249 <command>Alias=foo.service.wants/bar.service</command>
1250 in the same file. In case of template
1251 units, <command>systemctl enable</command>
1252 must be called with an instance name, and
1253 this instance will be added to the
1254 <filename>.wants/</filename> or
1255 <filename>.requires/</filename> list
1256 of the listed unit.
1257 E.g. <command>WantedBy=getty.target</command>
1258 in a service
1259 <filename>getty@.service</filename>
1260 will result in <command>systemctl
1261 enable getty@tty2.service</command>
1262 creating a
1263 <filename>getty.target.wants/getty@tty2.service</filename>
1264 link to <filename>getty@.service</filename>.
1265 </para></listitem>
1266 </varlistentry>
1267
1268 <varlistentry>
1269 <term><varname>Also=</varname></term>
1270
1271 <listitem><para>Additional units to
1272 install/deinstall when this unit is
1273 installed/deinstalled. If the user
1274 requests installation/deinstallation
1275 of a unit with this option configured,
1276 <command>systemctl enable</command>
1277 and <command>systemctl
1278 disable</command> will automatically
1279 install/uninstall units listed in this option as
1280 well.</para>
1281
1282 <para>This option may be used more
1283 than once, or a space-separated list
1284 of unit names may be
1285 given.</para></listitem>
1286 </varlistentry>
1287 </variablelist>
1288
1289 <para>The following specifiers are interpreted in the
1290 Install section: %n, %N, %p, %i, %U, %u, %m, %H, %b, %v.
1291 For their meaning see the next section.
1292 </para>
1293 </refsect1>
1294
1295 <refsect1>
1296 <title>Specifiers</title>
1297
1298 <para>Many settings resolve specifiers which may be
1299 used to write generic unit files referring to runtime
1300 or unit parameters that are replaced when the unit
1301 files are loaded. The following specifiers are
1302 understood:</para>
1303
1304 <table>
1305 <title>Specifiers available in unit files</title>
1306 <tgroup cols='3' align='left' colsep='1' rowsep='1'>
1307 <colspec colname="spec" />
1308 <colspec colname="mean" />
1309 <colspec colname="detail" />
1310 <thead>
1311 <row>
1312 <entry>Specifier</entry>
1313 <entry>Meaning</entry>
1314 <entry>Details</entry>
1315 </row>
1316 </thead>
1317 <tbody>
1318 <row>
1319 <entry><literal>%n</literal></entry>
1320 <entry>Full unit name</entry>
1321 <entry></entry>
1322 </row>
1323 <row>
1324 <entry><literal>%N</literal></entry>
1325 <entry>Unescaped full unit name</entry>
1326 <entry>Same as <literal>%n</literal>, but with escaping undone</entry>
1327 </row>
1328 <row>
1329 <entry><literal>%p</literal></entry>
1330 <entry>Prefix name</entry>
1331 <entry>For instantiated units, this refers to the string before the <literal>@</literal> character of the unit name. For non-instantiated units, this refers to the name of the unit with the type suffix removed.</entry>
1332 </row>
1333 <row>
1334 <entry><literal>%P</literal></entry>
1335 <entry>Unescaped prefix name</entry>
1336 <entry>Same as <literal>%p</literal>, but with escaping undone</entry>
1337 </row>
1338 <row>
1339 <entry><literal>%i</literal></entry>
1340 <entry>Instance name</entry>
1341 <entry>For instantiated units: this is the string between the <literal>@</literal> character and the suffix of the unit name.</entry>
1342 </row>
1343 <row>
1344 <entry><literal>%I</literal></entry>
1345 <entry>Unescaped instance name</entry>
1346 <entry>Same as <literal>%i</literal>, but with escaping undone</entry>
1347 </row>
1348 <row>
1349 <entry><literal>%f</literal></entry>
1350 <entry>Unescaped filename</entry>
1351 <entry>This is either the unescaped instance name (if applicable) with <filename>/</filename> prepended (if applicable), or the prefix name prepended with <filename>/</filename>.</entry>
1352 </row>
1353 <row>
1354 <entry><literal>%c</literal></entry>
1355 <entry>Control group path of the unit</entry>
1356 <entry>This path does not include the <filename>/sys/fs/cgroup/systemd/</filename> prefix.</entry>
1357 </row>
1358 <row>
1359 <entry><literal>%r</literal></entry>
1360 <entry>Control group path of the slice the unit is placed in</entry>
1361 <entry>This usually maps to the parent cgroup path of <literal>%c</literal>.</entry>
1362 </row>
1363 <row>
1364 <entry><literal>%R</literal></entry>
1365 <entry>Root control group path below which slices and units are placed</entry>
1366 <entry>For system instances, this resolves to <filename>/</filename>, except in containers, where this maps to the container's root control group path.</entry>
1367 </row>
1368 <row>
1369 <entry><literal>%t</literal></entry>
1370 <entry>Runtime directory</entry>
1371 <entry>This is either <filename>/run</filename> (for the system manager) or the path <literal>$XDG_RUNTIME_DIR</literal> resolves to (for user managers).</entry>
1372 </row>
1373 <row>
1374 <entry><literal>%u</literal></entry>
1375 <entry>User name</entry>
1376 <entry>This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
1377 </row>
1378 <row>
1379 <entry><literal>%U</literal></entry>
1380 <entry>User UID</entry>
1381 <entry>This is the numeric UID of the configured user of the unit, or (if none is set) the user running the systemd user instance. Note that this specifier is not available for units run by the systemd system instance (as opposed to those run by a systemd user instance), unless the user has been configured as a numeric UID in the first place or the configured user is the root user.</entry>
1382 </row>
1383 <row>
1384 <entry><literal>%h</literal></entry>
1385 <entry>User home directory</entry>
1386 <entry>This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd user instance. Similar to <literal>%U</literal>, this specifier is not available for units run by the systemd system instance, unless the configured user is the root user.</entry>
1387 </row>
1388 <row>
1389 <entry><literal>%s</literal></entry>
1390 <entry>User shell</entry>
1391 <entry>This is the shell of the configured user of the unit, or (if none is set) the user running the systemd user instance. Similar to <literal>%U</literal>, this specifier is not available for units run by the systemd system instance, unless the configured user is the root user.</entry>
1392 </row>
1393 <row>
1394 <entry><literal>%m</literal></entry>
1395 <entry>Machine ID</entry>
1396 <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
1397 </row>
1398 <row>
1399 <entry><literal>%b</literal></entry>
1400 <entry>Boot ID</entry>
1401 <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
1402 </row>
1403 <row>
1404 <entry><literal>%H</literal></entry>
1405 <entry>Host name</entry>
1406 <entry>The hostname of the running system at the point in time the unit configuation is loaded.</entry>
1407 </row>
1408 <row>
1409 <entry><literal>%v</literal></entry>
1410 <entry>Kernel release</entry>
1411 <entry>Identical to <command>uname -r</command> output</entry>
1412 </row>
1413 <row>
1414 <entry><literal>%%</literal></entry>
1415 <entry>Single percent sign</entry>
1416 <entry>Use <literal>%%</literal> in place of <literal>%</literal> to specify a single percent sign.</entry>
1417 </row>
1418 </tbody>
1419 </tgroup>
1420 </table>
1421 </refsect1>
1422
1423 <refsect1>
1424 <title>See Also</title>
1425 <para>
1426 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1427 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1428 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1429 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1430 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1431 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1432 <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1433 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1434 <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1435 <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1436 <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1437 <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1438 <citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1439 <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1440 <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1441 <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1442 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1443 <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1444 <citerefentry><refentrytitle>uname</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1445 </para>
1446 </refsect1>
1447
1448 </refentry>