man: systemd.unit(5): add examples for common tasks
[thirdparty/systemd.git] / man / systemd.service.xml
CommitLineData
d1ab0ca0
LP
1<?xml version='1.0'?> <!--*-nxml-*-->
2<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
3<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
4 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5
6<!--
7 This file is part of systemd.
8
9 Copyright 2010 Lennart Poettering
10
11 systemd is free software; you can redistribute it and/or modify it
5430f7f2
LP
12 under the terms of the GNU Lesser General Public License as published by
13 the Free Software Foundation; either version 2.1 of the License, or
d1ab0ca0
LP
14 (at your option) any later version.
15
16 systemd is distributed in the hope that it will be useful, but
17 WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
5430f7f2 19 Lesser General Public License for more details.
d1ab0ca0 20
5430f7f2 21 You should have received a copy of the GNU Lesser General Public License
d1ab0ca0
LP
22 along with systemd; If not, see <http://www.gnu.org/licenses/>.
23-->
24
25<refentry id="systemd.service">
26 <refentryinfo>
27 <title>systemd.service</title>
28 <productname>systemd</productname>
29
30 <authorgroup>
31 <author>
32 <contrib>Developer</contrib>
33 <firstname>Lennart</firstname>
34 <surname>Poettering</surname>
35 <email>lennart@poettering.net</email>
36 </author>
37 </authorgroup>
38 </refentryinfo>
39
40 <refmeta>
41 <refentrytitle>systemd.service</refentrytitle>
42 <manvolnum>5</manvolnum>
43 </refmeta>
44
45 <refnamediv>
46 <refname>systemd.service</refname>
34511ca7 47 <refpurpose>Service unit configuration</refpurpose>
d1ab0ca0
LP
48 </refnamediv>
49
50 <refsynopsisdiv>
e670b166 51 <para><filename><replaceable>service</replaceable>.service</filename></para>
d1ab0ca0
LP
52 </refsynopsisdiv>
53
54 <refsect1>
55 <title>Description</title>
56
1f812fea 57 <para>A unit configuration file whose name ends in
65232ea7
LP
58 <filename>.service</filename> encodes information
59 about a process controlled and supervised by
60 systemd.</para>
d1ab0ca0
LP
61
62 <para>This man page lists the configuration options
63 specific to this unit type. See
64 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
65 for the common options of all unit configuration
0d624a78 66 files. The common configuration items are configured
62adf224
LP
67 in the generic <literal>[Unit]</literal> and
68 <literal>[Install]</literal> sections. The service
69 specific configuration options are configured in the
70 <literal>[Service]</literal> section.</para>
0d624a78 71
ba60f905
LP
72 <para>Additional options are listed in
73 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
74 which define the execution environment the commands
4819ff03 75 are executed in, and in
d868475a 76 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4819ff03 77 which define the way the processes of the service are
d868475a 78 terminated, and in
3fde5f30
LP
79 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
80 which configure resource control settings for the
d868475a 81 processes of the service.</para>
62adf224
LP
82
83 <para>Unless <varname>DefaultDependencies=</varname>
84 is set to <option>false</option>, service units will
85 implicitly have dependencies of type
86 <varname>Requires=</varname> and
87 <varname>After=</varname> on
88 <filename>basic.target</filename> as well as
89 dependencies of type <varname>Conflicts=</varname> and
90 <varname>Before=</varname> on
91 <filename>shutdown.target</filename>. These ensure
92 that normal service units pull in basic system
93 initialization, and are terminated cleanly prior to
94 system shutdown. Only services involved with early
95 boot or late system shutdown should disable this
96 option.</para>
59a3e1bc
LP
97
98 <para>If a service is requested under a certain name
99 but no unit configuration file is found, systemd looks
100 for a SysV init script by the same name (with the
101 <filename>.service</filename> suffix removed) and
102 dynamically creates a service unit from that
103 script. This is useful for compatibility with
99800333
LP
104 SysV. Note that this compatibility is quite
105 comprehensive but not 100%. For details about the
bcddd5bf 106 incompatibilities, see the <ulink
99800333
LP
107 url="http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities">Incompatibilities
108 with SysV</ulink> document.
109 </para>
d1ab0ca0
LP
110 </refsect1>
111
112 <refsect1>
113 <title>Options</title>
114
62adf224
LP
115 <para>Service files must include a
116 <literal>[Service]</literal> section, which carries
117 information about the service and the process it
118 supervises. A number of options that may be used in
119 this section are shared with other unit types. These
120 options are documented in
4819ff03
LP
121 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
122 and
123 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
62adf224
LP
124 options specific to the <literal>[Service]</literal>
125 section of service units are the following:</para>
0d624a78 126
ccc9a4f9 127 <variablelist class='unit-directives'>
d1ab0ca0
LP
128 <varlistentry>
129 <term><varname>Type=</varname></term>
0d624a78
LP
130
131 <listitem><para>Configures the process
132 start-up type for this service
133 unit. One of <option>simple</option>,
134 <option>forking</option>,
34e9ba66 135 <option>oneshot</option>,
0d624a78 136 <option>dbus</option>,
a8ad0f89
LP
137 <option>notify</option> or
138 <option>idle</option>.</para>
0d624a78
LP
139
140 <para>If set to
141 <option>simple</option> (the default
96fb8242 142 if neither
12b25f30 143 <varname>Type=</varname> nor
96fb8242
LP
144 <varname>BusName=</varname>, but
145 <varname>ExecStart=</varname> are
12b25f30
ZJS
146 specified), it is expected that the
147 process configured with
0d624a78
LP
148 <varname>ExecStart=</varname> is the
149 main process of the service. In this
b1690fe7
LP
150 mode, if the process offers
151 functionality to other processes on
79640424 152 the system, its communication channels
b1690fe7
LP
153 should be installed before the daemon
154 is started up (e.g. sockets set up by
155 systemd, via socket activation), as
156 systemd will immediately proceed
157 starting follow-up units.</para>
0d624a78
LP
158
159 <para>If set to
79640424 160 <option>forking</option>, it is
0d624a78
LP
161 expected that the process configured
162 with <varname>ExecStart=</varname>
b1690fe7
LP
163 will call <function>fork()</function>
164 as part of its start-up. The parent process is
165 expected to exit when start-up is
166 complete and all communication
79640424 167 channels are set up. The child continues
b1690fe7 168 to run as the main daemon
c5315881 169 process. This is the behavior of
b1690fe7 170 traditional UNIX daemons. If this
0d624a78
LP
171 setting is used, it is recommended to
172 also use the
173 <varname>PIDFile=</varname> option, so
174 that systemd can identify the main
175 process of the daemon. systemd will
bcddd5bf
JSJ
176 proceed with starting follow-up units
177 as soon as the parent process
0d624a78
LP
178 exits.</para>
179
c5315881 180 <para>Behavior of
96fb8242
LP
181 <option>oneshot</option> is similar to
182 <option>simple</option>; however, it
183 is expected that the process has to
0d624a78 184 exit before systemd starts follow-up
02ee865a 185 units. <varname>RemainAfterExit=</varname>
0d624a78 186 is particularly useful for this type
96fb8242
LP
187 of service. This is the implied
188 default if neither
189 <varname>Type=</varname> or
190 <varname>ExecStart=</varname> are
191 specified.</para>
0d624a78 192
c5315881 193 <para>Behavior of
0d624a78 194 <option>dbus</option> is similar to
bcddd5bf 195 <option>simple</option>; however, it is
62adf224 196 expected that the daemon acquires a
0d624a78
LP
197 name on the D-Bus bus, as configured
198 by
199 <varname>BusName=</varname>. systemd
bcddd5bf
JSJ
200 will proceed with starting follow-up
201 units after the D-Bus bus name has been
62adf224 202 acquired. Service units with this
b1690fe7 203 option configured implicitly gain
62adf224 204 dependencies on the
177b3ffe 205 <filename>dbus.socket</filename>
0b86feac
LP
206 unit. This type is the default if
207 <varname>BusName=</varname> is
208 specified.</para>
0d624a78 209
c5315881 210 <para>Behavior of
0d624a78 211 <option>notify</option> is similar to
bcddd5bf 212 <option>simple</option>; however, it is
0d624a78
LP
213 expected that the daemon sends a
214 notification message via
215 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
bcddd5bf
JSJ
216 or an equivalent call when it has finished
217 starting up. systemd will proceed with
0d624a78
LP
218 starting follow-up units after this
219 notification message has been sent. If
79640424 220 this option is used,
62adf224 221 <varname>NotifyAccess=</varname> (see
b1690fe7 222 below) should be set to open access to
0d624a78 223 the notification socket provided by
62adf224 224 systemd. If
02c4ef9c
LP
225 <varname>NotifyAccess=</varname> is
226 not set, it will be implicitly set to
1361a3e3
LP
227 <option>main</option>. Note that
228 currently
229 <varname>Type=</varname><option>notify</option>
79640424 230 will not work if used in combination with
1361a3e3 231 <varname>PrivateNetwork=</varname><option>yes</option>.</para>
a8ad0f89 232
c5315881 233 <para>Behavior of
a8ad0f89 234 <option>idle</option> is very similar
bcddd5bf 235 to <option>simple</option>; however,
bb31a4ac 236 actual execution of the service
a8ad0f89
LP
237 binary is delayed until all jobs are
238 dispatched. This may be used to avoid
239 interleaving of output of shell
240 services with the status output on the
241 console.</para>
d1ab0ca0
LP
242 </listitem>
243 </varlistentry>
0d624a78 244
d1ab0ca0 245 <varlistentry>
02ee865a 246 <term><varname>RemainAfterExit=</varname></term>
0d624a78
LP
247
248 <listitem><para>Takes a boolean value
249 that specifies whether the service
250 shall be considered active even when
251 all its processes exited. Defaults to
252 <option>no</option>.</para>
d1ab0ca0 253 </listitem>
3185a36b
LP
254 </varlistentry>
255
256 <varlistentry>
257 <term><varname>GuessMainPID=</varname></term>
258
259 <listitem><para>Takes a boolean value
260 that specifies whether systemd should
261 try to guess the main PID of a service
bb31a4ac 262 if it cannot be determined
3185a36b
LP
263 reliably. This option is ignored
264 unless <option>Type=forking</option>
265 is set and <option>PIDFile=</option>
266 is unset because for the other types
267 or with an explicitly configured PID
bcddd5bf 268 file, the main PID is always known. The
3185a36b
LP
269 guessing algorithm might come to
270 incorrect conclusions if a daemon
271 consists of more than one process. If
79640424 272 the main PID cannot be determined,
3185a36b
LP
273 failure detection and automatic
274 restarting of a service will not work
275 reliably. Defaults to
276 <option>yes</option>.</para>
277 </listitem>
d1ab0ca0
LP
278 </varlistentry>
279
280 <varlistentry>
281 <term><varname>PIDFile=</varname></term>
0d624a78
LP
282
283 <listitem><para>Takes an absolute file
284 name pointing to the PID file of this
285 daemon. Use of this option is
286 recommended for services where
287 <varname>Type=</varname> is set to
be039669
LP
288 <option>forking</option>. systemd will
289 read the PID of the main process of
290 the daemon after start-up of the
291 service. systemd will not write to the
292 file configured here.</para>
d1ab0ca0
LP
293 </listitem>
294 </varlistentry>
295
296 <varlistentry>
297 <term><varname>BusName=</varname></term>
0d624a78
LP
298
299 <listitem><para>Takes a D-Bus bus
bcddd5bf 300 name that this service is reachable
0d624a78
LP
301 as. This option is mandatory for
302 services where
303 <varname>Type=</varname> is set to
f4e9cdbc 304 <option>dbus</option>.</para>
d1ab0ca0
LP
305 </listitem>
306 </varlistentry>
307
50199623
DM
308 <varlistentry>
309 <term><varname>BusPolicy=</varname></term>
310
9c77924c
ZJS
311 <listitem><para>If specified, a custom
312 <ulink url="https://code.google.com/p/d-bus/">kdbus</ulink>
50199623
DM
313 endpoint will be created and installed as the
314 default bus node for the service. Such a custom
315 endpoint can hold an own set of policy rules
316 that are enforced on top of the bus-wide ones.
317 The custom endpoint is named after the service
318 it was created for, and its node will be
319 bind-mounted over the default bus node
320 location, so the service can only access the
321 bus through its own endpoint. Note that custom
322 bus endpoints default to a 'deny all' policy.
323 Hence, if at least one
324 <varname>BusPolicy=</varname> directive is
325 given, you have to make sure to add explicit
326 rules for everything the service should be able
327 to do.</para>
328 <para>The value of this directive is comprised
329 of two parts; the bus name, and a verb to
330 specify to granted access, which is one of
331 <option>see</option>,
9c77924c 332 <option>talk</option>, or
50199623
DM
333 <option>own</option>.
334 <option>talk</option> implies
335 <option>see</option>, and <option>own</option>
336 implies both <option>talk</option> and
337 <option>see</option>.
338 If multiple access levels are specified for the
339 same bus name, the most powerful one takes
340 effect.
341 </para>
342 <para>Examples:</para>
343 <programlisting>BusPolicy=org.freedesktop.systemd1 talk</programlisting>
344 <programlisting>BusPolicy=org.foo.bar see</programlisting>
345 <para>This option is only available on kdbus enabled systems.</para>
346 </listitem>
347 </varlistentry>
348
d1ab0ca0
LP
349 <varlistentry>
350 <term><varname>ExecStart=</varname></term>
22f38abe
LP
351 <listitem><para>Commands with their
352 arguments that are executed when this
30d88d54
ZJS
353 service is started. The value is split
354 into zero or more command lines is
355 according to the rules described below
356 (see section "Command Lines" below).
357 </para>
2480f0c6 358
4c42e8e1
ZJS
359 <para>When <varname>Type</varname> is
360 not <option>oneshot</option>, only one
96fb8242 361 command may and must be given. When
b1690fe7 362 <varname>Type=oneshot</varname> is
30d88d54
ZJS
363 used, zero or more commands may be
364 specified. This can be specified by
365 providing multiple command lines in
97426dcf 366 the same directive, or alternatively,
30d88d54
ZJS
367 this directive may be specified more
368 than once with the same effect. If the
369 empty string is assigned to this
370 option, the list of commands to start
371 is reset, prior assignments of this
372 option will have no effect. If no
96fb8242
LP
373 <varname>ExecStart=</varname> is
374 specified, then the service must have
375 <varname>RemainAfterExit=yes</varname>
376 set.</para>
2480f0c6 377
30d88d54
ZJS
378 <para>For each of the specified
379 commands, the first argument must be
c8539536
ZJS
380 an absolute path to an executable.
381 Optionally, if this file name is
382 prefixed with <literal>@</literal>,
383 the second token will be passed as
30d88d54
ZJS
384 <literal>argv[0]</literal> to the
385 executed process, followed by the
386 further arguments specified. If the
387 absolute filename is prefixed with
388 <literal>-</literal>, an exit code of
389 the command normally considered a
390 failure (i.e. non-zero exit status or
391 abnormal exit due to signal) is
392 ignored and considered success. If
393 both <literal>-</literal> and
394 <literal>@</literal> are used, they
395 can appear in either order.</para>
ec6039bc 396
4c42e8e1
ZJS
397 <para>If more than one command is
398 specified, the commands are invoked
bcddd5bf
JSJ
399 sequentially in the order they appear
400 in the unit file. If one of the
401 commands fails (and is not prefixed
30d88d54
ZJS
402 with <literal>-</literal>), other
403 lines are not executed, and the unit
404 is considered failed.</para>
4c42e8e1 405
2480f0c6
ZJS
406 <para>Unless
407 <varname>Type=forking</varname> is
408 set, the process started via this
409 command line will be considered the
22f38abe
LP
410 main process of the daemon.</para>
411
ec6039bc 412 </listitem>
0d624a78
LP
413 </varlistentry>
414
415 <varlistentry>
416 <term><varname>ExecStartPre=</varname></term>
417 <term><varname>ExecStartPost=</varname></term>
418 <listitem><para>Additional commands
16dad32e 419 that are executed before or after
0d624a78 420 the command in
2480f0c6
ZJS
421 <varname>ExecStart=</varname>, respectively.
422 Syntax is the same as for
423 <varname>ExecStart=</varname>, except
424 that multiple command lines are allowed
425 and the commands are executed one
426 after the other, serially.</para>
4c42e8e1
ZJS
427
428 <para>If any of those commands (not
909f413d 429 prefixed with <literal>-</literal>)
4c42e8e1
ZJS
430 fail, the rest are not executed and
431 the unit is considered failed.</para>
2480f0c6 432 </listitem>
0d624a78
LP
433 </varlistentry>
434
435 <varlistentry>
436 <term><varname>ExecReload=</varname></term>
437 <listitem><para>Commands to execute to
438 trigger a configuration reload in the
b3eaa628
LP
439 service. This argument takes multiple
440 command lines, following the same
2480f0c6
ZJS
441 scheme as described for
442 <varname>ExecStart=</varname>
b3eaa628 443 above. Use of this setting is
420a0166
LP
444 optional. Specifier and environment
445 variable substitution is supported
446 here following the same scheme as for
4c42e8e1
ZJS
447 <varname>ExecStart=</varname>.</para>
448
bcddd5bf
JSJ
449 <para>One additional, special
450 environment variable is set: if known,
4c42e8e1 451 <varname>$MAINPID</varname> is set to
97ae63e2
LP
452 the main process of the daemon, and
453 may be used for command lines like the
4c42e8e1
ZJS
454 following:</para>
455
456 <programlisting>/bin/kill -HUP $MAINPID</programlisting>
33169701
LP
457
458 <para>Note however that reloading a
459 daemon by sending a signal (as with
460 the example line above) is usually not
461 a good choice, because this is an
462 asynchronous operation and hence not
463 suitable to order reloads of multiple
464 services against each other. It is
465 strongly recommended to set
466 <varname>ExecReload=</varname> to a
851fafe5 467 command that not only triggers a
33169701 468 configuration reload of the daemon,
851fafe5 469 but also synchronously waits for it to
33169701 470 complete.</para>
4c42e8e1 471 </listitem>
0d624a78
LP
472 </varlistentry>
473
474 <varlistentry>
475 <term><varname>ExecStop=</varname></term>
476 <listitem><para>Commands to execute to
477 stop the service started via
b3eaa628
LP
478 <varname>ExecStart=</varname>. This
479 argument takes multiple command lines,
2480f0c6
ZJS
480 following the same scheme as described
481 for <varname>ExecStart=</varname>
b3eaa628 482 above. Use of this setting is
bcddd5bf
JSJ
483 optional. After the commands configured
484 in this option are run, all processes
485 remaining for a service are
0d624a78
LP
486 terminated according to the
487 <varname>KillMode=</varname> setting
4819ff03
LP
488 (see
489 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>). If
79640424 490 this option is not specified, the
bcddd5bf 491 process is terminated immediately when
4819ff03
LP
492 service stop is requested. Specifier
493 and environment variable substitution
494 is supported (including
4c42e8e1 495 <varname>$MAINPID</varname>, see
420a0166 496 above).</para></listitem>
0d624a78
LP
497 </varlistentry>
498
499 <varlistentry>
500 <term><varname>ExecStopPost=</varname></term>
501 <listitem><para>Additional commands
502 that are executed after the service
3ae390ba
MB
503 was stopped. This includes cases where
504 the commands configured in
505 <varname>ExecStop=</varname> were used,
6b4991cf 506 where the service does not have any
3ae390ba
MB
507 <varname>ExecStop=</varname> defined, or
508 where the service exited unexpectedly. This
b3eaa628 509 argument takes multiple command lines,
2480f0c6
ZJS
510 following the same scheme as described
511 for <varname>ExecStart</varname>. Use
b3eaa628 512 of these settings is
420a0166
LP
513 optional. Specifier and environment
514 variable substitution is
515 supported.</para></listitem>
0d624a78
LP
516 </varlistentry>
517
518 <varlistentry>
519 <term><varname>RestartSec=</varname></term>
520 <listitem><para>Configures the time to
521 sleep before restarting a service (as
522 configured with
523 <varname>Restart=</varname>). Takes a
524 unit-less value in seconds, or a time
525 span value such as "5min
526 20s". Defaults to
527 100ms.</para></listitem>
528 </varlistentry>
529
530 <varlistentry>
d568a335 531 <term><varname>TimeoutStartSec=</varname></term>
0d624a78 532 <listitem><para>Configures the time to
d568a335 533 wait for start-up. If a
0d624a78
LP
534 daemon service does not signal
535 start-up completion within the
d568a335 536 configured time, the service will be
bcddd5bf
JSJ
537 considered failed and will be shut
538 down again.
d568a335
MS
539 Takes a unit-less value in seconds, or a
540 time span value such as "5min
bcddd5bf
JSJ
541 20s". Pass <literal>0</literal> to
542 disable the timeout logic. Defaults to
5e34b37c 543 <varname>DefaultTimeoutStartSec=</varname> from
bcddd5bf
JSJ
544 the manager configuration file, except
545 when <varname>Type=oneshot</varname> is
63ba209d 546 used, in which case the timeout
5e34b37c 547 is disabled by default
97426dcf 548 (see <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
d568a335
MS
549 </para></listitem>
550 </varlistentry>
551
552 <varlistentry>
553 <term><varname>TimeoutStopSec=</varname></term>
554 <listitem><para>Configures the time to
555 wait for stop. If a service is asked
bcddd5bf 556 to stop, but does not terminate in the
d568a335 557 specified time, it will be terminated
bcddd5bf
JSJ
558 forcibly via <constant>SIGTERM</constant>,
559 and after another timeout of equal duration
560 with <constant>SIGKILL</constant> (see
62adf224 561 <varname>KillMode=</varname>
d568a335
MS
562 in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
563 Takes a unit-less value in seconds, or a
0d624a78 564 time span value such as "5min
bcddd5bf
JSJ
565 20s". Pass <literal>0</literal> to disable
566 the timeout logic. Defaults to
5e34b37c
ZJS
567 <varname>DefaultTimeoutStopSec=</varname> from the
568 manager configuration file
97426dcf 569 (see <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
d568a335
MS
570 </para></listitem>
571 </varlistentry>
572
573 <varlistentry>
574 <term><varname>TimeoutSec=</varname></term>
575 <listitem><para>A shorthand for configuring
576 both <varname>TimeoutStartSec=</varname>
577 and <varname>TimeoutStopSec=</varname>
578 to the specified value.
579 </para></listitem>
0d624a78
LP
580 </varlistentry>
581
bb242b7b
MO
582 <varlistentry>
583 <term><varname>WatchdogSec=</varname></term>
e8ab3ccb 584 <listitem><para>Configures the
a827e373
ZJS
585 watchdog timeout for a service. The
586 watchdog is activated when the start-up is
e8ab3ccb 587 completed. The service must call
bb242b7b 588 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
bcddd5bf
JSJ
589 regularly with <literal>WATCHDOG=1</literal>
590 (i.e. the "keep-alive ping"). If the time
dac051ad 591 between two such calls is larger than
79640424 592 the configured time, then the service
db2cb23b
UTL
593 is placed in a failed state and it will
594 be terminated with <varname>SIGABRT</varname>.
595 By setting <varname>Restart=</varname> to
dac051ad 596 <option>on-failure</option> or
79640424 597 <option>always</option>, the service
e8ab3ccb
LP
598 will be automatically restarted. The
599 time configured here will be passed to
600 the executed service process in the
601 <varname>WATCHDOG_USEC=</varname>
dac051ad
LP
602 environment variable. This allows
603 daemons to automatically enable the
604 keep-alive pinging logic if watchdog
605 support is enabled for the service. If
79640424 606 this option is used,
02c4ef9c
LP
607 <varname>NotifyAccess=</varname> (see
608 below) should be set to open access to
609 the notification socket provided by
610 systemd. If
dac051ad
LP
611 <varname>NotifyAccess=</varname> is
612 not set, it will be implicitly set to
02c4ef9c 613 <option>main</option>. Defaults to 0,
e8ab3ccb
LP
614 which disables this
615 feature.</para></listitem>
bb242b7b
MO
616 </varlistentry>
617
0d624a78
LP
618 <varlistentry>
619 <term><varname>Restart=</varname></term>
620 <listitem><para>Configures whether the
a827e373
ZJS
621 service shall be restarted when the
622 service process exits, is killed,
623 or a timeout is reached. The service
624 process may be the main service
bcddd5bf
JSJ
625 process, but it may also be one of the
626 processes specified with
a827e373
ZJS
627 <varname>ExecStartPre=</varname>,
628 <varname>ExecStartPost=</varname>,
c32acc96 629 <varname>ExecStop=</varname>,
a827e373
ZJS
630 <varname>ExecStopPost=</varname>, or
631 <varname>ExecReload=</varname>.
632 When the death of the process is a
633 result of systemd operation (e.g. service
634 stop or restart), the service will not be
635 restarted. Timeouts include missing
636 the watchdog "keep-alive ping"
637 deadline and a service start, reload,
638 and stop operation timeouts.</para>
639
640 <para>Takes one of
525ee6f4 641 <option>no</option>,
50caaedb
LP
642 <option>on-success</option>,
643 <option>on-failure</option>,
6cfe2fde 644 <option>on-abnormal</option>,
dc99a976 645 <option>on-watchdog</option>,
a827e373 646 <option>on-abort</option>, or
50caaedb 647 <option>always</option>. If set to
79640424 648 <option>no</option> (the default), the
6cfe2fde
LP
649 service will not be restarted. If set
650 to <option>on-success</option>, it
651 will be restarted only when the
652 service process exits cleanly. In
653 this context, a clean exit means an
654 exit code of 0, or one of the signals
bcddd5bf
JSJ
655 <constant>SIGHUP</constant>,
656 <constant>SIGINT</constant>,
6cfe2fde
LP
657 <constant>SIGTERM</constant> or
658 <constant>SIGPIPE</constant>, and
659 additionally, exit statuses and
660 signals specified in
661 <varname>SuccessExitStatus=</varname>.
79640424 662 If set to <option>on-failure</option>,
a827e373 663 the service will be restarted when the
6cfe2fde
LP
664 process exits with a non-zero exit
665 code, is terminated by a signal
666 (including on core dump, but excluding
667 the aforementiond four signals), when
668 an operation (such as service reload)
669 times out, and when the configured
670 watchdog timeout is triggered. If set
671 to <option>on-abnormal</option>, the
672 service will be restarted when the
673 process is terminated by a signal
674 (including on core dump, excluding the
675 aforementioned four signals), when an
676 operation times out, or when the
677 watchdog timeout is triggered. If set
678 to <option>on-abort</option>, the
679 service will be restarted only if the
680 service process exits due to an
681 uncaught signal not specified as a
682 clean exit status. If set to
683 <option>on-watchdog</option>, the
684 service will be restarted only if the
685 watchdog timeout for the service
686 expires. If set to
79640424 687 <option>always</option>, the service
6cfe2fde
LP
688 will be restarted regardless of
689 whether it exited cleanly or not, got
bcddd5bf 690 terminated abnormally by a signal, or
a827e373
ZJS
691 hit a timeout.</para>
692
6cfe2fde
LP
693 <table>
694 <title>Exit causes and the effect of the <varname>Restart=</varname> settings on them</title>
695
696 <tgroup cols='2'>
697 <colspec colname='path' />
698 <colspec colname='expl' />
699 <thead>
700 <row>
701 <entry>Restart settings/Exit causes</entry>
702 <entry><option>no</option></entry>
703 <entry><option>always</option></entry>
704 <entry><option>on-success</option></entry>
705 <entry><option>on-failure</option></entry>
706 <entry><option>on-abnormal</option></entry>
707 <entry><option>on-abort</option></entry>
708 <entry><option>on-watchdog</option></entry>
709 </row>
710 </thead>
711 <tbody>
712 <row>
713 <entry>Clean exit code or signal</entry>
714 <entry/>
715 <entry>X</entry>
716 <entry>X</entry>
717 <entry/>
718 <entry/>
719 <entry/>
720 <entry/>
721 </row>
722 <row>
723 <entry>Unclean exit code</entry>
724 <entry/>
725 <entry>X</entry>
726 <entry/>
727 <entry>X</entry>
728 <entry/>
729 <entry/>
730 <entry/>
731 </row>
732 <row>
733 <entry>Unclean signal</entry>
734 <entry/>
735 <entry>X</entry>
736 <entry/>
737 <entry>X</entry>
738 <entry>X</entry>
739 <entry>X</entry>
740 <entry/>
741 </row>
742 <row>
743 <entry>Timeout</entry>
744 <entry/>
745 <entry>X</entry>
746 <entry/>
747 <entry>X</entry>
748 <entry>X</entry>
749 <entry/>
750 <entry/>
751 </row>
752 <row>
753 <entry>Watchdog</entry>
754 <entry/>
755 <entry>X</entry>
756 <entry/>
757 <entry>X</entry>
758 <entry>X</entry>
759 <entry/>
760 <entry>X</entry>
761 </row>
762 </tbody>
763 </tgroup>
764 </table>
765
ab016c45
LP
766 <para>As exceptions to the setting
767 above the service will not be
768 restarted if the exit code or signal
769 is specified in
a827e373 770 <varname>RestartPreventExitStatus=</varname>
ab016c45
LP
771 (see below). Also, the services will
772 always be restarted if the exit code
773 or signal is specified in
774 <varname>RestartForceExitStatus=</varname>
6cfe2fde
LP
775 (see below).</para>
776
777 <para>Setting this to
778 <option>on-failure</option> is the
779 recommended choice for long-running
780 services, in order to increase
781 reliability by attempting automatic
782 recovery from errors. For services
783 that shall be able to terminate on
ab016c45
LP
784 their own choice (and avoid
785 immediate restarting),
6cfe2fde
LP
786 <option>on-abnormal</option> is an
787 alternative choice.</para>
788 </listitem>
0d624a78
LP
789 </varlistentry>
790
96342de6 791 <varlistentry>
abdf7993
LP
792 <term><varname>SuccessExitStatus=</varname></term>
793 <listitem><para>Takes a list of exit
794 status definitions that when returned
795 by the main service process will be
796 considered successful termination, in
797 addition to the normal successful exit
05cc7267 798 code 0 and the signals <constant>SIGHUP</constant>, <constant>SIGINT</constant>,
a9a30533 799 <constant>SIGTERM</constant>, and <constant>SIGPIPE</constant>. Exit status
abdf7993 800 definitions can either be numeric exit
a827e373 801 codes or termination signal names,
4a3fa6ac 802 separated by spaces. For example:
37520c1b 803 <programlisting>SuccessExitStatus=1 2 8 SIGKILL</programlisting>
73e231ab
JE
804 ensures that exit codes 1, 2, 8 and
805 the termination signal
806 <constant>SIGKILL</constant> are
807 considered clean service terminations.
808 </para>
809
810 <para>Note that if a process has a
811 signal handler installed and exits by
812 calling
813 <citerefentry><refentrytitle>_exit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
814 in response to a signal, the
815 information about the signal is lost.
816 Programs should instead perform cleanup and kill themselves with the same signal instead. See
817 <ulink url="http://www.cons.org/cracauer/sigint.html">Proper handling of SIGINT/SIGQUIT — How to be a proper program</ulink>.</para>
818
819 <para>This option may appear more than once,
820 in which case the list of successful
821 exit statuses is merged. If the empty
822 string is assigned to this option, the
823 list is reset, all prior assignments
824 of this option will have no
825 effect.</para></listitem>
96342de6
LN
826 </varlistentry>
827
828 <varlistentry>
abdf7993
LP
829 <term><varname>RestartPreventExitStatus=</varname></term>
830 <listitem><para>Takes a list of exit
831 status definitions that when returned
832 by the main service process will
bcddd5bf 833 prevent automatic service restarts,
abdf7993
LP
834 regardless of the restart setting
835 configured with
836 <varname>Restart=</varname>. Exit
837 status definitions can either be
838 numeric exit codes or termination
839 signal names, and are separated by
840 spaces. Defaults to the empty list, so
bcddd5bf 841 that, by default, no exit status is
abdf7993 842 excluded from the configured restart
37520c1b
LP
843 logic. For example:
844 <programlisting>RestartPreventExitStatus=1 6 SIGABRT</programlisting> ensures that exit
74051b9b 845 codes 1 and 6 and the termination
bcddd5bf
JSJ
846 signal <constant>SIGABRT</constant> will
847 not result in automatic service
848 restarting. This
849 option may appear more than once, in
850 which case the list of restart-preventing
74051b9b 851 statuses is merged. If the empty
79640424 852 string is assigned to this option, the
bcddd5bf 853 list is reset and all prior assignments
74051b9b
LP
854 of this option will have no
855 effect.</para></listitem>
96342de6
LN
856 </varlistentry>
857
37520c1b
LP
858 <varlistentry>
859 <term><varname>RestartForceExitStatus=</varname></term>
860 <listitem><para>Takes a list of exit
861 status definitions that when returned
862 by the main service process will force
863 automatic service restarts, regardless
864 of the restart setting configured with
865 <varname>Restart=</varname>. The
866 argument format is similar to
867 <varname>RestartPreventExitStatus=</varname>.</para></listitem>
868 </varlistentry>
869
0d624a78
LP
870 <varlistentry>
871 <term><varname>PermissionsStartOnly=</varname></term>
872 <listitem><para>Takes a boolean
bcddd5bf
JSJ
873 argument. If true, the permission-related
874 execution options, as
0d624a78
LP
875 configured with
876 <varname>User=</varname> and similar
877 options (see
878 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
bcddd5bf 879 for more information), are only applied
0d624a78
LP
880 to the process started with
881 <varname>ExecStart=</varname>, and not
882 to the various other
883 <varname>ExecStartPre=</varname>,
884 <varname>ExecStartPost=</varname>,
885 <varname>ExecReload=</varname>,
bcddd5bf 886 <varname>ExecStop=</varname>, and
0d624a78
LP
887 <varname>ExecStopPost=</varname>
888 commands. If false, the setting is
889 applied to all configured commands the
890 same way. Defaults to
891 false.</para></listitem>
892 </varlistentry>
893
894 <varlistentry>
895 <term><varname>RootDirectoryStartOnly=</varname></term>
896 <listitem><para>Takes a boolean
bcddd5bf 897 argument. If true, the root directory,
0d624a78
LP
898 as configured with the
899 <varname>RootDirectory=</varname>
900 option (see
901 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
bcddd5bf 902 for more information), is only applied
0d624a78
LP
903 to the process started with
904 <varname>ExecStart=</varname>, and not
905 to the various other
906 <varname>ExecStartPre=</varname>,
907 <varname>ExecStartPost=</varname>,
908 <varname>ExecReload=</varname>,
bcddd5bf 909 <varname>ExecStop=</varname>, and
0d624a78
LP
910 <varname>ExecStopPost=</varname>
911 commands. If false, the setting is
912 applied to all configured commands the
913 same way. Defaults to
914 false.</para></listitem>
915 </varlistentry>
916
0d624a78
LP
917 <varlistentry>
918 <term><varname>NonBlocking=</varname></term>
bcddd5bf
JSJ
919 <listitem><para>Set the
920 <constant>O_NONBLOCK</constant> flag
0d624a78
LP
921 for all file descriptors passed via
922 socket-based activation. If true, all
923 file descriptors >= 3 (i.e. all except
6db27428 924 stdin, stdout, and stderr) will have
bcddd5bf
JSJ
925 the <constant>O_NONBLOCK</constant> flag
926 set and hence are in
0d624a78
LP
927 non-blocking mode. This option is only
928 useful in conjunction with a socket
929 unit, as described in
930 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Defaults
931 to false.</para></listitem>
932 </varlistentry>
933
934 <varlistentry>
935 <term><varname>NotifyAccess=</varname></term>
936 <listitem><para>Controls access to the
937 service status notification socket, as
938 accessible via the
939 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
940 call. Takes one of
941 <option>none</option> (the default),
942 <option>main</option> or
943 <option>all</option>. If
79640424 944 <option>none</option>, no daemon status
f8553ccb 945 updates are accepted from the service
0d624a78 946 processes, all status update messages
79640424 947 are ignored. If <option>main</option>,
0d624a78
LP
948 only service updates sent from the
949 main process of the service are
79640424 950 accepted. If <option>all</option>, all
0d624a78
LP
951 services updates from all members of
952 the service's control group are
02c4ef9c 953 accepted. This option should be set to
0d624a78
LP
954 open access to the notification socket
955 when using
02c4ef9c 956 <varname>Type=notify</varname> or
28137202 957 <varname>WatchdogSec=</varname> (see
02c4ef9c 958 above). If those options are used but
79640424
JE
959 <varname>NotifyAccess=</varname> is not
960 configured, it will be implicitly set
02c4ef9c
LP
961 to
962 <option>main</option>.</para></listitem>
d1ab0ca0
LP
963 </varlistentry>
964
f72192c0
LP
965 <varlistentry>
966 <term><varname>Sockets=</varname></term>
967 <listitem><para>Specifies the name of
968 the socket units this service shall
388ce344
LP
969 inherit socket file descriptors
970 from when the service is
971 started. Normally it should not be
972 necessary to use this setting as all
973 socket file descriptors whose unit
f72192c0 974 shares the same name as the service
388ce344
LP
975 (subject to the different unit name
976 suffix of course) are passed to the
977 spawned process.</para>
978
979 <para>Note that the same socket file
980 descriptors may be passed to multiple
981 processes simultaneously. Also note
982 that a different service may be
983 activated on incoming socket traffic
984 than the one which is ultimately
985 configured to inherit the socket file
986 descriptors. Or in other words: the
f72192c0
LP
987 <varname>Service=</varname> setting of
988 <filename>.socket</filename> units
6b4991cf 989 does not have to match the inverse of
74051b9b
LP
990 the <varname>Sockets=</varname>
991 setting of the
992 <filename>.service</filename> it
993 refers to.</para>
994
995 <para>This option may appear more than
996 once, in which case the list of socket
997 units is merged. If the empty string
79640424 998 is assigned to this option, the list of
bcddd5bf 999 sockets is reset, and all prior uses of
74051b9b
LP
1000 this setting will have no
1001 effect.</para></listitem>
f72192c0
LP
1002 </varlistentry>
1003
092317d0
LP
1004 <varlistentry>
1005 <term><varname>StartLimitInterval=</varname></term>
1006 <term><varname>StartLimitBurst=</varname></term>
1007
1008 <listitem><para>Configure service
79640424 1009 start rate limiting. By default,
bcddd5bf
JSJ
1010 services which are started more
1011 than 5 times within 10 seconds are not
092317d0 1012 permitted to start any more times
bcddd5bf 1013 until the 10 second interval ends. With
79640424 1014 these two options, this rate limiting
092317d0
LP
1015 may be modified. Use
1016 <varname>StartLimitInterval=</varname>
3f41e1e5
LN
1017 to configure the checking interval (defaults to
1018 <varname>DefaultStartLimitInterval=</varname> in
1019 manager configuration file, set to 0 to disable
092317d0
LP
1020 any kind of rate limiting). Use
1021 <varname>StartLimitBurst=</varname> to
1022 configure how many starts per interval
3f41e1e5
LN
1023 are allowed (defaults to
1024 <varname>DefaultStartLimitBurst=</varname> in
1025 manager configuration file). These
092317d0
LP
1026 configuration options are particularly
1027 useful in conjunction with
bcddd5bf
JSJ
1028 <varname>Restart=</varname>; however,
1029 they apply to all kinds of starts
6ffd3337
LP
1030 (including manual), not just those
1031 triggered by the
1032 <varname>Restart=</varname> logic.
1033 Note that units which are configured
1034 for <varname>Restart=</varname> and
1035 which reach the start limit are not
bcddd5bf
JSJ
1036 attempted to be restarted anymore;
1037 however, they may still be restarted
1038 manually at a later point, from which
1039 point on, the restart logic is again
451b34cc
LP
1040 activated. Note that
1041 <command>systemctl
1042 reset-failed</command> will cause the
1043 restart rate counter for a service to
1044 be flushed, which is useful if the
1045 administrator wants to manually start
1046 a service and the start limit
1047 interferes with
1048 that.</para></listitem>
092317d0
LP
1049 </varlistentry>
1050
1051 <varlistentry>
1052 <term><varname>StartLimitAction=</varname></term>
1053
1054 <listitem><para>Configure the action
1055 to take if the rate limit configured
1056 with
1057 <varname>StartLimitInterval=</varname>
1058 and
1059 <varname>StartLimitBurst=</varname> is
1060 hit. Takes one of
1061 <option>none</option>,
1062 <option>reboot</option>,
f07756bf
LP
1063 <option>reboot-force</option>,
1064 <option>reboot-immediate</option>,
1065 <option>poweroff</option>,
1066 <option>poweroff-force</option> or
1067 <option>poweroff-immediate</option>. If
1068 <option>none</option> is set, hitting
1069 the rate limit will trigger no action
1070 besides that the start will not be
1071 permitted. <option>reboot</option>
092317d0
LP
1072 causes a reboot following the normal
1073 shutdown procedure (i.e. equivalent to
bcddd5bf 1074 <command>systemctl reboot</command>).
f07756bf
LP
1075 <option>reboot-force</option> causes a
1076 forced reboot which will terminate all
1077 processes forcibly but should cause no
1078 dirty file systems on reboot
092317d0
LP
1079 (i.e. equivalent to <command>systemctl
1080 reboot -f</command>) and
1081 <option>reboot-immediate</option>
1082 causes immediate execution of the
1083 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
1084 system call, which might result in
f07756bf
LP
1085 data loss. Similar,
1086 <option>poweroff</option>,
1087 <option>poweroff-force</option>,
1088 <option>poweroff-immediate</option>
1089 have the effect of powering down the
1090 system with similar
1091 semantics. Defaults to
092317d0
LP
1092 <option>none</option>.</para></listitem>
1093 </varlistentry>
1094
2928b0a8
LP
1095 <varlistentry>
1096 <term><varname>FailureAction=</varname></term>
1097 <listitem><para>Configure the action
1098 to take when the service enters a failed
1099 state. Takes the same values as
1100 <varname>StartLimitAction=</varname>
1101 and executes the same actions.
1102 Defaults to <option>none</option>.
1103 </para></listitem>
1104 </varlistentry>
1105
efe6e7d3
MO
1106 <varlistentry>
1107 <term><varname>RebootArgument=</varname></term>
1108 <listitem><para>Configure the optional
1109 argument for the
1110 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
1111 system call if
1112 <varname>StartLimitAction=</varname>
2928b0a8 1113 or <varname>FailureAction=</varname>
efe6e7d3
MO
1114 is a reboot action. This works just
1115 like the optional argument to
1116 <command>systemctl reboot</command>
1117 command.</para></listitem>
1118 </varlistentry>
1119
a354329f
LP
1120 <varlistentry>
1121 <term><varname>FileDescriptorStoreMax=</varname></term>
1122 <listitem><para>Configure how many
1123 file descriptors may be stored in the
1124 service manager for the service using
1125 <citerefentry><refentrytitle>sd_pid_notify_with_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>'s
1126 <literal>FDSTORE=1</literal>
1127 messages. This is useful for
1128 implementing service restart schemes
1129 where the state is serialized to
1130 <filename>/run</filename> and the file
1131 descriptors passed to the service
1132 manager, to allow restarts without
1133 losing state. Defaults to 0, i.e. no
1134 file descriptors may be stored in the
1135 service manager by default. All file
1136 descriptors passed to the service
1137 manager from a specific service are
1138 passed back to the service's main
1139 process on the next service
1140 restart. Any file descriptors passed
1141 to the service manager are
1142 automatically closed when POLLHUP or
1143 POLLERR is seen on them, or when the
1144 service is fully stopped and no job
1145 queued or being executed for
1146 it.</para></listitem>
1147 </varlistentry>
1148
d1ab0ca0 1149 </variablelist>
4819ff03
LP
1150
1151 <para>Check
1152 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1153 and
1154 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1155 for more settings.</para>
1156
d1ab0ca0
LP
1157 </refsect1>
1158
30d88d54
ZJS
1159 <refsect1>
1160 <title>Command lines</title>
1161
1162 <para>This section describes command line parsing and
1163 variable and specifier substitions for
1164 <varname>ExecStart=</varname>,
1165 <varname>ExecStartPre=</varname>,
1166 <varname>ExecStartPost=</varname>,
1167 <varname>ExecReload=</varname>,
1168 <varname>ExecStop=</varname>, and
1169 <varname>ExecStopPost=</varname> options.</para>
1170
1171 <para>Multiple command lines may be concatenated in a
1172 single directive by separating them with semicolons
1173 (these semicolons must be passed as separate words).
1174 Lone semicolons may be escaped as
1175 <literal>\;</literal>.</para>
1176
1177 <para>Each command line is split on whitespace, with
1178 the first item being the command to execute, and the
c8539536 1179 subsequent items being the arguments. Double quotes
30d88d54
ZJS
1180 ("...") and single quotes ('...') may be used, in
1181 which case everything until the next matching quote
c8539536
ZJS
1182 becomes part of the same argument. C-style escapes are
1183 also supported, see table below. Quotes themselves are
1184 removed after parsing and escape sequences
1185 substituted. In addition, a trailing backslash
1186 (<literal>\</literal>) may be used to merge lines.
1187 </para>
30d88d54
ZJS
1188
1189 <para>This syntax is intended to be very similar to
1190 shell syntax, but only the meta-characters and
1191 expansions described in the following paragraphs are
1192 understood. Specifically, redirection using
1193 <literal>&lt;</literal>, <literal>&lt;&lt;</literal>,
1194 <literal>&gt;</literal>, and
1195 <literal>&gt;&gt;</literal>, pipes using
1196 <literal>|</literal>, running programs in the
1197 background using <literal>&amp;</literal>, and
1198 <emphasis>other elements of shell syntax are not
1199 supported</emphasis>.</para>
1200
c8539536
ZJS
1201 <para>The command to execute must an absolute path
1202 name. It may contain spaces, but control characters
1203 are not allowed.</para>
1204
30d88d54
ZJS
1205 <para>The command line accepts <literal>%</literal>
1206 specifiers as described in
1207 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1208 Note that the first argument of the command line
1209 (i.e. the program to execute) may not include
1210 specifiers.</para>
1211
1212 <para>Basic environment variable substitution is
1213 supported. Use <literal>${FOO}</literal> as part of a
1214 word, or as a word of its own, on the command line, in
1215 which case it will be replaced by the value of the
1216 environment variable including all whitespace it
1217 contains, resulting in a single argument. Use
1218 <literal>$FOO</literal> as a separate word on the
1219 command line, in which case it will be replaced by the
5d9a2698
ZJS
1220 value of the environment variable split at whitespace
1221 resulting in zero or more arguments. For this type of
1222 expansion, quotes and respected when splitting into
1223 words, and afterwards removed.</para>
1224
1225 <para>Example:</para>
1226
1227 <programlisting>Environment="ONE=one" 'TWO=two two'
1228ExecStart=/bin/echo $ONE $TWO ${TWO}</programlisting>
1229
1230 <para>This will execute <command>/bin/echo</command>
1231 with four arguments: <literal>one</literal>,
1232 <literal>two</literal>, <literal>two</literal>, and
1233 <literal>two two</literal>.</para>
1234
1235 <para>Example:</para>
1236 <programlisting>Environment=ONE='one' "TWO='two two' too" THREE=
1237ExecStart=/bin/echo ${ONE} ${TWO} ${THREE}
1238ExecStart=/bin/echo $ONE $TWO $THREE</programlisting>
1239 <para>This results in <filename>echo</filename> being
1240 called twice, the first time with arguments
1241 <literal>'one'</literal>,
1242 <literal>'two two' too</literal>, <literal></literal>,
1243 and the second time with arguments
1244 <literal>one</literal>, <literal>two two</literal>,
1245 <literal>too</literal>.
1246 </para>
1247
1248 <para>To pass a literal dollar sign, use
1249 <literal>$$</literal>. Variables whose value is not
1250 known at expansion time are treated as empty
1251 strings. Note that the first argument (i.e. the
1252 program to execute) may not be a variable.</para>
30d88d54
ZJS
1253
1254 <para>Variables to be used in this fashion may be
1255 defined through <varname>Environment=</varname> and
1256 <varname>EnvironmentFile=</varname>. In addition,
1257 variables listed in the section "Environment variables
1258 in spawned processes" in
1259 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1260 which are considered "static configuration", may be
1261 used (this includes e.g. <varname>$USER</varname>, but
1262 not <varname>$TERM</varname>).</para>
1263
1264 <para>Note that shell command lines are not directly
1265 supported. If shell command lines are to be used, they
1266 need to be passed explicitly to a shell implementation
1267 of some kind. Example:</para>
1268 <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'</programlisting>
1269
1270 <para>Example:</para>
1271
1272 <programlisting>ExecStart=/bin/echo one ; /bin/echo "two two"</programlisting>
1273
1274 <para>This will execute <command>/bin/echo</command>
1275 two times, each time with one argument:
1276 <literal>one</literal> and <literal>two two</literal>,
1277 respectively. Because two commands are specified,
1278 <varname>Type=oneshot</varname> must be used.</para>
1279
1280 <para>Example:</para>
1281
1282 <programlisting>ExecStart=/bin/echo / &gt;/dev/null &amp; \; \
1283/bin/ls</programlisting>
1284
1285 <para>This will execute <command>/bin/echo</command>
1286 with five arguments: <literal>/</literal>,
1287 <literal>&gt;/dev/null</literal>,
1288 <literal>&amp;</literal>, <literal>;</literal>, and
1289 <literal>/bin/ls</literal>.</para>
c8539536
ZJS
1290
1291 <table>
1292 <title>C escapes supported in command lines and environment variables</title>
1293 <tgroup cols='2'>
1294 <colspec colname='escape' />
1295 <colspec colname='meaning' />
1296 <thead>
1297 <row>
1298 <entry>Literal</entry>
1299 <entry>Actual value</entry>
1300 </row>
1301 </thead>
1302 <tbody>
1303 <row>
1304 <entry><literal>\a</literal></entry>
1305 <entry>bell</entry>
1306 </row>
1307 <row>
1308 <entry><literal>\b</literal></entry>
1309 <entry>backspace</entry>
1310 </row>
1311 <row>
1312 <entry><literal>\f</literal></entry>
1313 <entry>form feed</entry>
1314 </row>
1315 <row>
1316 <entry><literal>\n</literal></entry>
1317 <entry>newline</entry>
1318 </row>
1319 <row>
1320 <entry><literal>\r</literal></entry>
1321 <entry>carriage return</entry>
1322 </row>
1323 <row>
1324 <entry><literal>\t</literal></entry>
1325 <entry>tab</entry>
1326 </row>
1327 <row>
1328 <entry><literal>\v</literal></entry>
1329 <entry>vertical tab</entry>
1330 </row>
1331 <row>
1332 <entry><literal>\\</literal></entry>
1333 <entry>backslash</entry>
1334 </row>
1335 <row>
1336 <entry><literal>\"</literal></entry>
1337 <entry>double quotation mark</entry>
1338 </row>
1339 <row>
1340 <entry><literal>\'</literal></entry>
1341 <entry>single quotation mark</entry>
1342 </row>
1343 <row>
1344 <entry><literal>\s</literal></entry>
1345 <entry>space</entry>
1346 </row>
1347 <row>
1348 <entry><literal>\x<replaceable>xx</replaceable></literal></entry>
1349 <entry>character number <replaceable>xx</replaceable> in hexadecimal encoding</entry>
1350 </row>
1351 <row>
1352 <entry><literal>\<replaceable>nnn</replaceable></literal></entry>
1353 <entry>character number <replaceable>nnn</replaceable> in octal encoding</entry>
1354 </row>
1355 </tbody>
1356 </tgroup>
1357 </table>
30d88d54 1358 </refsect1>
c485d3ba 1359
d1ab0ca0
LP
1360 <refsect1>
1361 <title>See Also</title>
1362 <para>
f3e219a2 1363 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
67826132 1364 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
0d624a78 1365 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
4819ff03 1366 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
3fde5f30 1367 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
9cc2c8b7
ZJS
1368 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1369 <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
d1ab0ca0
LP
1370 </para>
1371 </refsect1>
1372
1373</refentry>