man/systemd-run.xml

   1 <?xml version='1.0'?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   5
   6 <refentry id="systemd-run"
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd-run</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd-run</refentrytitle>
  16     <manvolnum>1</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd-run</refname>
  21     <refpurpose>Run programs in transient scope units, service units, or path-, socket-, or timer-triggered service units</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <cmdsynopsis>
  26       <command>systemd-run</command>
  27       <arg choice="opt" rep="repeat">OPTIONS</arg>
  28       <arg choice="plain"><replaceable>COMMAND</replaceable>
  29       <arg choice="opt" rep="repeat">ARGS</arg>
  30       </arg>
  31     </cmdsynopsis>
  32     <cmdsynopsis>
  33       <command>systemd-run</command>
  34       <arg choice="opt" rep="repeat">OPTIONS</arg>
  35       <arg choice="opt" rep="repeat">PATH OPTIONS</arg>
  36       <arg choice="req"><replaceable>COMMAND</replaceable></arg>
  37       <arg choice="opt" rep="repeat">ARGS</arg>
  38     </cmdsynopsis>
  39     <cmdsynopsis>
  40       <command>systemd-run</command>
  41       <arg choice="opt" rep="repeat">OPTIONS</arg>
  42       <arg choice="opt" rep="repeat">SOCKET OPTIONS</arg>
  43       <arg choice="req"><replaceable>COMMAND</replaceable></arg>
  44       <arg choice="opt" rep="repeat">ARGS</arg>
  45     </cmdsynopsis>
  46     <cmdsynopsis>
  47       <command>systemd-run</command>
  48       <arg choice="opt" rep="repeat">OPTIONS</arg>
  49       <arg choice="opt" rep="repeat">TIMER OPTIONS</arg>
  50       <arg choice="req"><replaceable>COMMAND</replaceable></arg>
  51       <arg choice="opt" rep="repeat">ARGS</arg>
  52     </cmdsynopsis>
  53   </refsynopsisdiv>
  54
  55   <refsect1>
  56     <title>Description</title>
  57
  58     <para><command>systemd-run</command> may be used to create and start a transient <filename>.service</filename> or
  59     <filename>.scope</filename> unit and run the specified <replaceable>COMMAND</replaceable> in it. It may also be
  60     used to create and start a transient <filename>.path</filename>, <filename>.socket</filename>, or
  61     <filename>.timer</filename> unit, that activates a <filename>.service</filename> unit when elapsing.</para>
  62
  63     <para>If a command is run as transient service unit, it will be started and managed by the service manager like any
  64     other service, and thus shows up in the output of <command>systemctl list-units</command> like any other unit. It
  65     will run in a clean and detached execution environment, with the service manager as its parent process. In this
  66     mode, <command>systemd-run</command> will start the service asynchronously in the background and return after the
  67     command has begun execution (unless <option>--no-block</option> or <option>--wait</option> are specified, see
  68     below).</para>
  69
  70     <para>If a command is run as transient scope unit, it will be executed by <command>systemd-run</command>
  71     itself as parent process and will thus inherit the execution environment of the caller. However, the
  72     processes of the command are managed by the service manager similarly to normal services, and will show
  73     up in the output of <command>systemctl list-units</command>. Execution in this case is synchronous, and
  74     will return only when the command finishes. This mode is enabled via the <option>--scope</option> switch
  75     (see below).</para>
  76
  77     <para>If a command is run with path, socket, or timer options such as <option>--on-calendar=</option> (see below),
  78     a transient path, socket, or timer unit is created alongside the service unit for the specified command. Only the
  79     transient path, socket, or timer unit is started immediately, the transient service unit will be triggered by the
  80     path, socket, or timer unit. If the <option>--unit=</option> option is specified, the
  81     <replaceable>COMMAND</replaceable> may be omitted. In this case, <command>systemd-run</command> creates only a
  82     <filename>.path</filename>, <filename>.socket</filename>, or <filename>.timer</filename> unit that triggers the
  83     specified unit.</para>
  84
  85     <para>By default, services created with <command>systemd-run</command> default to the
  86     <option>simple</option> type, see the description of <varname>Type=</varname> in
  87     <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
  88     details. Note that when this type is used, the service manager (and thus the
  89     <command>systemd-run</command> command) considers service start-up successful as soon as the
  90     <function>fork()</function> for the main service process succeeded, i.e. before the
  91     <function>execve()</function> is invoked, and thus even if the specified command cannot be started.
  92     Consider using the <option>exec</option> service type (i.e. <option>--property=Type=exec</option>) to
  93     ensure that <command>systemd-run</command> returns successfully only if the specified command line has
  94     been successfully started.</para>
  95   </refsect1>
  96
  97   <refsect1>
  98     <title>Options</title>
  99
 100     <para>The following options are understood:</para>
 101
 102     <variablelist>
 103       <varlistentry>
 104         <term><option>--no-ask-password</option></term>
 105
 106         <listitem><para>Do not query the user for authentication for
 107         privileged operations.</para></listitem>
 108       </varlistentry>
 109
 110       <varlistentry>
 111         <term><option>--scope</option></term>
 112
 113         <listitem>
 114           <para>Create a transient <filename>.scope</filename> unit instead of the default transient
 115           <filename>.service</filename> unit (see above).
 116           </para>
 117         </listitem>
 118       </varlistentry>
 119
 120       <varlistentry>
 121         <term><option>--unit=</option></term>
 122         <term><option>-u</option></term>
 123
 124         <listitem><para>Use this unit name instead of an automatically
 125         generated one.</para></listitem>
 126       </varlistentry>
 127
 128       <varlistentry>
 129         <term><option>--property=</option></term>
 130         <term><option>-p</option></term>
 131
 132         <listitem><para>Sets a property on the scope or service unit that is created. This option takes an assignment
 133         in the same format as
 134         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
 135         <command>set-property</command> command.</para>
 136         </listitem>
 137       </varlistentry>
 138
 139       <varlistentry>
 140         <term><option>--description=</option></term>
 141
 142         <listitem><para>Provide a description for the service, scope, path, socket, or timer unit. If not specified,
 143         the command itself will be used as a description. See <varname>Description=</varname> in
 144         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 145         </para></listitem>
 146       </varlistentry>
 147
 148       <varlistentry>
 149         <term><option>--slice=</option></term>
 150
 151         <listitem><para>Make the new <filename>.service</filename> or <filename>.scope</filename> unit part
 152         of the specified slice, instead of <filename>system.slice</filename> (when running in
 153         <option>--system</option> mode) or the root slice (when running in <option>--user</option>
 154         mode).</para>
 155         </listitem>
 156       </varlistentry>
 157
 158       <varlistentry>
 159         <term><option>--slice-inherit</option></term>
 160
 161         <listitem><para>Make the new <filename>.service</filename> or <filename>.scope</filename> unit part
 162         of the inherited slice. This option can be combined with <option>--slice=</option>.</para>
 163
 164         <para>An inherited slice is located within <command>systemd-run</command> slice. Example: if
 165         <command>systemd-run</command> slice is <filename>foo.slice</filename>, and the
 166         <option>--slice=</option> argument is <filename>bar</filename>, the unit will be placed under the
 167         <filename>foo-bar.slice</filename>.</para>
 168
 169         </listitem>
 170       </varlistentry>
 171
 172       <varlistentry>
 173         <term><option>-r</option></term>
 174         <term><option>--remain-after-exit</option></term>
 175
 176         <listitem><para>After the service process has terminated, keep the service around until it is explicitly
 177         stopped. This is useful to collect runtime information about the service after it finished running. Also see
 178         <varname>RemainAfterExit=</varname> in
 179         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 180         </para>
 181         </listitem>
 182       </varlistentry>
 183
 184       <varlistentry>
 185         <term><option>--send-sighup</option></term>
 186
 187         <listitem><para>When terminating the scope or service unit, send a SIGHUP immediately after SIGTERM. This is
 188         useful to indicate to shells and shell-like processes that the connection has been severed. Also see
 189         <varname>SendSIGHUP=</varname> in
 190         <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 191         </para>
 192         </listitem>
 193       </varlistentry>
 194
 195       <varlistentry>
 196         <term><option>--service-type=</option></term>
 197
 198         <listitem><para>Sets the service type. Also see
 199         <varname>Type=</varname> in
 200         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>. This
 201         option has no effect in conjunction with
 202         <option>--scope</option>. Defaults to
 203         <constant>simple</constant>.</para>
 204         </listitem>
 205       </varlistentry>
 206
 207       <varlistentry>
 208         <term><option>--uid=</option></term>
 209         <term><option>--gid=</option></term>
 210
 211         <listitem><para>Runs the service process under the specified UNIX user and group. Also see
 212         <varname>User=</varname> and <varname>Group=</varname> in
 213         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 214         </listitem>
 215       </varlistentry>
 216
 217       <varlistentry>
 218         <term><option>--nice=</option></term>
 219
 220         <listitem><para>Runs the service process with the specified
 221         nice level. Also see <varname>Nice=</varname> in
 222         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 223         </listitem>
 224       </varlistentry>
 225
 226       <varlistentry>
 227         <term><option>--working-directory=</option></term>
 228
 229         <listitem><para>Runs the service process with the specified working directory. Also see
 230         <varname>WorkingDirectory=</varname> in
 231         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 232         </listitem>
 233       </varlistentry>
 234
 235       <varlistentry>
 236         <term><option>--same-dir</option></term>
 237         <term><option>-d</option></term>
 238
 239         <listitem><para>Similar to <option>--working-directory=</option>, but uses the current working
 240         directory of the caller for the service to execute.</para></listitem>
 241       </varlistentry>
 242
 243       <varlistentry>
 244         <term><option>-E <replaceable>NAME</replaceable>[=<replaceable>VALUE</replaceable>]</option></term>
 245         <term><option>--setenv=<replaceable>NAME</replaceable>[=<replaceable>VALUE</replaceable>]</option></term>
 246
 247         <listitem><para>Runs the service process with the specified environment variable set. This parameter
 248         may be used more than once to set multiple variables. When <literal>=</literal> and
 249         <replaceable>VALUE</replaceable> are omitted, the value of the variable with the same name in the
 250         program environment will be used.</para>
 251
 252         <para>Also see <varname>Environment=</varname> in
 253         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 254         </listitem>
 255       </varlistentry>
 256
 257       <varlistentry>
 258         <term><option>--pty</option></term>
 259         <term><option>-t</option></term>
 260
 261         <listitem><para>When invoking the command, the transient service connects its standard input, output and error
 262         to the terminal <command>systemd-run</command> is invoked on, via a pseudo TTY device. This allows running
 263         programs that expect interactive user input/output as services, such as interactive command shells.</para>
 264
 265         <para>Note that
 266         <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
 267         <command>shell</command> command is usually a better alternative for requesting a new, interactive login
 268         session on the local host or a local container.</para>
 269
 270         <para>See below for details on how this switch combines with <option>--pipe</option>.</para></listitem>
 271       </varlistentry>
 272
 273       <varlistentry>
 274         <term><option>--pipe</option></term>
 275         <term><option>-P</option></term>
 276
 277         <listitem><para>If specified, standard input, output, and error of the transient service are inherited from the
 278         <command>systemd-run</command> command itself. This allows <command>systemd-run</command>
 279         to be used within shell pipelines.
 280         Note that this mode is not suitable for interactive command shells and similar, as the
 281         service process will not become a TTY controller when invoked on a terminal. Use <option>--pty</option> instead
 282         in that case.</para>
 283
 284         <para>When both <option>--pipe</option> and <option>--pty</option> are used in combination the more appropriate
 285         option is automatically determined and used. Specifically, when invoked with standard input, output and error
 286         connected to a TTY <option>--pty</option> is used, and otherwise <option>--pipe</option>.</para>
 287
 288         <para>When this option is used the original file descriptors <command>systemd-run</command> receives are passed
 289         to the service processes as-is. If the service runs with different privileges than
 290         <command>systemd-run</command>, this means the service might not be able to re-open the passed file
 291         descriptors, due to normal file descriptor access restrictions. If the invoked process is a shell script that
 292         uses the <command>echo "hello" > /dev/stderr</command> construct for writing messages to stderr, this might
 293         cause problems, as this only works if stderr can be re-opened. To mitigate this use the construct <command>echo
 294         "hello" >&amp;2</command> instead, which is mostly equivalent and avoids this pitfall.</para></listitem>
 295       </varlistentry>
 296
 297       <varlistentry>
 298         <term><option>--shell</option></term>
 299         <term><option>-S</option></term>
 300
 301         <listitem><para>A shortcut for <literal>--pty --same-dir --wait --collect --service-type=exec $SHELL</literal>,
 302         i.e. requests an interactive shell in the current working directory, running in service context, accessible
 303         with a single switch.</para></listitem>
 304       </varlistentry>
 305
 306       <varlistentry>
 307         <term><option>--quiet</option></term>
 308         <term><option>-q</option></term>
 309
 310         <listitem><para>Suppresses additional informational output
 311         while running. This is particularly useful in combination with
 312         <option>--pty</option> when it will suppress the initial
 313         message explaining how to terminate the TTY connection.</para></listitem>
 314       </varlistentry>
 315
 316       <varlistentry>
 317         <term><option>--on-active=</option></term>
 318         <term><option>--on-boot=</option></term>
 319         <term><option>--on-startup=</option></term>
 320         <term><option>--on-unit-active=</option></term>
 321         <term><option>--on-unit-inactive=</option></term>
 322
 323         <listitem><para>Defines a monotonic timer relative to different starting points for starting the specified
 324         command. See <varname>OnActiveSec=</varname>, <varname>OnBootSec=</varname>, <varname>OnStartupSec=</varname>,
 325         <varname>OnUnitActiveSec=</varname> and <varname>OnUnitInactiveSec=</varname> in
 326         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
 327         details. These options are shortcuts for <command>--timer-property=</command> with the relevant properties.
 328         These options may not be combined with <option>--scope</option> or <option>--pty</option>.</para>
 329         </listitem>
 330       </varlistentry>
 331
 332       <varlistentry>
 333         <term><option>--on-calendar=</option></term>
 334
 335         <listitem><para>Defines a calendar timer for starting the specified command. See <varname>OnCalendar=</varname>
 336         in <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>. This
 337         option is a shortcut for <command>--timer-property=OnCalendar=</command>. This option may not be combined with
 338         <option>--scope</option> or <option>--pty</option>.</para>
 339         </listitem>
 340       </varlistentry>
 341
 342       <varlistentry>
 343         <term><option>--on-clock-change</option></term>
 344         <term><option>--on-timezone-change</option></term>
 345
 346         <listitem><para>Defines a trigger based on system clock jumps or timezone changes for starting the
 347         specified command. See <varname>OnClockChange=</varname> and <varname>OnTimezoneChange=</varname> in
 348         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>. These
 349         options are shortcuts for <command>--timer-property=OnClockChange=yes</command> and
 350         <command>--timer-property=OnTimezoneChange=yes</command>. These options may not be combined with
 351         <option>--scope</option> or <option>--pty</option>.</para></listitem>
 352       </varlistentry>
 353
 354       <varlistentry>
 355         <term><option>--path-property=</option></term>
 356         <term><option>--socket-property=</option></term>
 357         <term><option>--timer-property=</option></term>
 358
 359         <listitem><para>Sets a property on the path, socket, or timer unit that is created. This option is
 360         similar to <option>--property=</option>, but applies to the transient path, socket, or timer unit
 361         rather than the transient service unit created. This option takes an assignment in the same format as
 362         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
 363         <command>set-property</command> command. These options may not be combined with
 364         <option>--scope</option> or <option>--pty</option>.</para>
 365         </listitem>
 366       </varlistentry>
 367
 368       <varlistentry>
 369         <term><option>--no-block</option></term>
 370
 371         <listitem>
 372           <para>Do not synchronously wait for the unit start operation to finish. If this option is not specified, the
 373           start request for the transient unit will be verified, enqueued and <command>systemd-run</command> will wait
 374           until the unit's start-up is completed. By passing this argument, it is only verified and enqueued. This
 375           option may not be combined with <option>--wait</option>.</para>
 376         </listitem>
 377       </varlistentry>
 378
 379       <varlistentry>
 380         <term><option>--wait</option></term>
 381
 382         <listitem><para>Synchronously wait for the transient service to terminate. If this option is specified, the
 383         start request for the transient unit is verified, enqueued, and waited for. Subsequently the invoked unit is
 384         monitored, and it is waited until it is deactivated again (most likely because the specified command
 385         completed). On exit, terse information about the unit's runtime is shown, including total runtime (as well as
 386         CPU usage, if <option>--property=CPUAccounting=1</option> was set) and the exit code and status of the main
 387         process. This output may be suppressed with <option>--quiet</option>. This option may not be combined with
 388         <option>--no-block</option>, <option>--scope</option> or the various path, socket, or timer options.</para></listitem>
 389       </varlistentry>
 390
 391       <varlistentry>
 392         <term><option>-G</option></term>
 393         <term><option>--collect</option></term>
 394
 395         <listitem><para>Unload the transient unit after it completed, even if it failed. Normally, without this option,
 396         all units that ran and failed are kept in memory until the user explicitly resets their failure state with
 397         <command>systemctl reset-failed</command> or an equivalent command. On the other hand, units that ran
 398         successfully are unloaded immediately. If this option is turned on the "garbage collection" of units is more
 399         aggressive, and unloads units regardless if they exited successfully or failed. This option is a shortcut for
 400         <command>--property=CollectMode=inactive-or-failed</command>, see the explanation for
 401         <varname>CollectMode=</varname> in
 402         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for further
 403         information.</para></listitem>
 404       </varlistentry>
 405
 406       <xi:include href="user-system-options.xml" xpointer="user" />
 407       <xi:include href="user-system-options.xml" xpointer="system" />
 408       <xi:include href="user-system-options.xml" xpointer="host" />
 409       <xi:include href="user-system-options.xml" xpointer="machine" />
 410
 411       <xi:include href="standard-options.xml" xpointer="help" />
 412       <xi:include href="standard-options.xml" xpointer="version" />
 413     </variablelist>
 414
 415     <para>All command line arguments after the first non-option argument become part of the command line of
 416     the launched process.</para>
 417   </refsect1>
 418
 419   <refsect1>
 420     <title>Exit status</title>
 421
 422     <para>On success, 0 is returned. If <command>systemd-run</command> failed to start the service, a
 423     non-zero return value will be returned. If <command>systemd-run</command> waits for the service to
 424     terminate, the return value will be propagated from the service. 0 will be returned on success, including
 425     all the cases where systemd considers a service to have exited cleanly, see the discussion of
 426     <varname>SuccessExitStatus=</varname> in
 427     <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 428     </para>
 429   </refsect1>
 430
 431   <refsect1>
 432     <title>Examples</title>
 433
 434     <example>
 435       <title>Logging environment variables provided by systemd to services</title>
 436
 437       <programlisting># systemd-run env
 438 Running as unit: run-19945.service
 439 # journalctl -u run-19945.service
 440 Sep 08 07:37:21 bupkis systemd[1]: Starting /usr/bin/env...
 441 Sep 08 07:37:21 bupkis systemd[1]: Started /usr/bin/env.
 442 Sep 08 07:37:21 bupkis env[19948]: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
 443 Sep 08 07:37:21 bupkis env[19948]: LANG=en_US.UTF-8
 444 Sep 08 07:37:21 bupkis env[19948]: BOOT_IMAGE=/vmlinuz-3.11.0-0.rc5.git6.2.fc20.x86_64</programlisting>
 445     </example>
 446
 447     <example>
 448       <title>Limiting resources available to a command</title>
 449
 450       <programlisting># systemd-run -p IOWeight=10 updatedb</programlisting>
 451
 452       <para>This command invokes the <citerefentry
 453       project='man-pages'><refentrytitle>updatedb</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 454       tool, but lowers the block I/O weight for it to 10. See
 455       <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 456       for more information on the <varname>IOWeight=</varname> property.</para>
 457     </example>
 458
 459     <example>
 460       <title>Running commands at a specified time</title>
 461
 462       <para>The following command will touch a file after 30 seconds.</para>
 463
 464       <programlisting># date; systemd-run --on-active=30 --timer-property=AccuracySec=100ms /bin/touch /tmp/foo
 465 Mon Dec  8 20:44:24 KST 2014
 466 Running as unit: run-71.timer
 467 Will run service as unit: run-71.service
 468 # journalctl -b -u run-71.timer
 469 -- Journal begins at Fri 2014-12-05 19:09:21 KST, ends at Mon 2014-12-08 20:44:54 KST. --
 470 Dec 08 20:44:38 container systemd[1]: Starting /bin/touch /tmp/foo.
 471 Dec 08 20:44:38 container systemd[1]: Started /bin/touch /tmp/foo.
 472 # journalctl -b -u run-71.service
 473 -- Journal begins at Fri 2014-12-05 19:09:21 KST, ends at Mon 2014-12-08 20:44:54 KST. --
 474 Dec 08 20:44:48 container systemd[1]: Starting /bin/touch /tmp/foo...
 475 Dec 08 20:44:48 container systemd[1]: Started /bin/touch /tmp/foo.</programlisting>
 476     </example>
 477
 478     <example>
 479       <title>Allowing access to the tty</title>
 480
 481       <para>The following command invokes <citerefentry project='man-pages'><refentrytitle>bash</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 482       as a service passing its standard input, output and error to the calling TTY.</para>
 483
 484       <programlisting># systemd-run -t --send-sighup bash</programlisting>
 485     </example>
 486
 487     <example>
 488       <title>Start <command>screen</command> as a user service</title>
 489
 490       <programlisting>$ systemd-run --scope --user screen
 491 Running scope as unit run-r14b0047ab6df45bfb45e7786cc839e76.scope.
 492
 493 $ screen -ls
 494 There is a screen on:
 495         492..laptop     (Detached)
 496 1 Socket in /var/run/screen/S-fatima.
 497 </programlisting>
 498
 499       <para>This starts the <command>screen</command> process as a child of the
 500       <command>systemd --user</command> process that was started by
 501       <filename>user@.service</filename>, in a scope unit. A
 502       <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 503       unit is used instead of a
 504       <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 505       unit, because <command>screen</command> will exit when detaching from the terminal,
 506       and a service unit would be terminated. Running <command>screen</command>
 507       as a user unit has the advantage that it is not part of the session scope.
 508       If <varname>KillUserProcesses=yes</varname> is configured in
 509       <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 510       the default, the session scope will be terminated when the user logs
 511       out of that session.</para>
 512
 513       <para>The <filename>user@.service</filename> is started automatically
 514       when the user first logs in, and stays around as long as at least one
 515       login session is open. After the user logs out of the last session,
 516       <filename>user@.service</filename> and all services underneath it
 517       are terminated. This behavior is the default, when "lingering" is
 518       not enabled for that user. Enabling lingering means that
 519       <filename>user@.service</filename> is started automatically during
 520       boot, even if the user is not logged in, and that the service is
 521       not terminated when the user logs out.</para>
 522
 523       <para>Enabling lingering allows the user to run processes without being logged in,
 524       for example to allow <command>screen</command> to persist after the user logs out,
 525       even if the session scope is terminated. In the default configuration, users can
 526       enable lingering for themselves:</para>
 527
 528       <programlisting>$ loginctl enable-linger</programlisting>
 529     </example>
 530
 531     <example>
 532       <title>Return value</title>
 533
 534       <programlisting>$ systemd-run --user --wait true
 535 $ systemd-run --user --wait -p SuccessExitStatus=11 bash -c 'exit 11'
 536 $ systemd-run --user --wait -p SuccessExitStatus=SIGUSR1 bash -c 'kill -SIGUSR1 $$$$'</programlisting>
 537
 538       <para>Those three invocations will succeed, i.e. terminate with an exit code of 0.</para>
 539     </example>
 540   </refsect1>
 541
 542   <refsect1>
 543     <title>See Also</title>
 544     <para>
 545       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 546       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 547       <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 548       <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 549       <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 550       <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 551       <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 552       <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 553       <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 554       <citerefentry><refentrytitle>systemd-mount</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 555       <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 556     </para>
 557   </refsect1>
 558
 559 </refentry>