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
  96     <para>After <command>systemd-run</command> passes the command to the service manager, the manager
  97     performs variable expansion. This means that dollar characters (<literal>$</literal>) which should not be
  98     expanded need to be escaped as <literal>$$</literal>. Expansion can also be disabled using
  99     <varname>--expand-environment=no</varname>.</para>
 100   </refsect1>
 101
 102   <refsect1>
 103     <title>Options</title>
 104
 105     <para>The following options are understood:</para>
 106
 107     <variablelist>
 108       <varlistentry>
 109         <term><option>--no-ask-password</option></term>
 110
 111         <listitem><para>Do not query the user for authentication for
 112         privileged operations.</para>
 113
 114         <xi:include href="version-info.xml" xpointer="v226"/></listitem>
 115       </varlistentry>
 116
 117       <varlistentry>
 118         <term><option>--scope</option></term>
 119
 120         <listitem>
 121           <para>Create a transient <filename>.scope</filename> unit instead of the default transient
 122           <filename>.service</filename> unit (see above).
 123           </para>
 124
 125         <xi:include href="version-info.xml" xpointer="v206"/>
 126         </listitem>
 127       </varlistentry>
 128
 129       <varlistentry>
 130         <term><option>--unit=</option></term>
 131         <term><option>-u</option></term>
 132
 133         <listitem><para>Use this unit name instead of an automatically
 134         generated one.</para></listitem>
 135       </varlistentry>
 136
 137       <varlistentry>
 138         <term><option>--property=</option></term>
 139         <term><option>-p</option></term>
 140
 141         <listitem><para>Sets a property on the scope or service unit that is created. This option takes an assignment
 142         in the same format as
 143         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
 144         <command>set-property</command> command.</para>
 145
 146         <xi:include href="version-info.xml" xpointer="v211"/>
 147         </listitem>
 148       </varlistentry>
 149
 150       <varlistentry>
 151         <term><option>--description=</option></term>
 152
 153         <listitem><para>Provide a description for the service, scope, path, socket, or timer unit. If not specified,
 154         the command itself will be used as a description. See <varname>Description=</varname> in
 155         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 156         </para>
 157
 158         <xi:include href="version-info.xml" xpointer="v206"/></listitem>
 159       </varlistentry>
 160
 161       <varlistentry>
 162         <term><option>--slice=</option></term>
 163
 164         <listitem><para>Make the new <filename>.service</filename> or <filename>.scope</filename> unit part
 165         of the specified slice, instead of <filename>system.slice</filename> (when running in
 166         <option>--system</option> mode) or the root slice (when running in <option>--user</option>
 167         mode).</para>
 168
 169         <xi:include href="version-info.xml" xpointer="v206"/>
 170         </listitem>
 171       </varlistentry>
 172
 173       <varlistentry>
 174         <term><option>--slice-inherit</option></term>
 175
 176         <listitem><para>Make the new <filename>.service</filename> or <filename>.scope</filename> unit part
 177         of the inherited slice. This option can be combined with <option>--slice=</option>.</para>
 178
 179         <para>An inherited slice is located within <command>systemd-run</command> slice. Example: if
 180         <command>systemd-run</command> slice is <filename>foo.slice</filename>, and the
 181         <option>--slice=</option> argument is <filename>bar</filename>, the unit will be placed under the
 182         <filename>foo-bar.slice</filename>.</para>
 183
 184         <xi:include href="version-info.xml" xpointer="v246"/>
 185
 186         </listitem>
 187       </varlistentry>
 188
 189       <varlistentry>
 190         <term><option>--expand-environment=<replaceable>BOOL</replaceable></option></term>
 191
 192         <listitem><para>Expand environment variables in command arguments. If enabled, environment variables
 193         specified as <literal>${<replaceable>VARIABLE</replaceable>}</literal> will be expanded in the same
 194         way as in commands specified via <varname>ExecStart=</varname> in units. With
 195         <varname>--scope</varname>, this expansion is performed by <command>systemd-run</command> itself, and
 196         in other cases by the service manager that spawns the command. Note that this is similar to, but not
 197         the same as variable expansion in
 198         <citerefentry project='man-pages'><refentrytitle>bash</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 199         and other shells.</para>
 200
 201         <para>The default is to enable this option in all cases, except for <varname>--scope</varname> where
 202         it is disabled by default, for backward compatibility reasons. Note that this will be changed in a
 203         future release, where it will be switched to enabled by default as well.</para>
 204
 205         <para>See
 206         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 207         for a description of variable expansion. Disabling variable expansion is useful if the specified
 208         command includes or may include a <literal>$</literal> sign.</para>
 209
 210         <xi:include href="version-info.xml" xpointer="v254"/>
 211         </listitem>
 212       </varlistentry>
 213
 214       <varlistentry>
 215         <term><option>-r</option></term>
 216         <term><option>--remain-after-exit</option></term>
 217
 218         <listitem><para>After the service process has terminated, keep the service around until it is explicitly
 219         stopped. This is useful to collect runtime information about the service after it finished running. Also see
 220         <varname>RemainAfterExit=</varname> in
 221         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 222         </para>
 223         </listitem>
 224       </varlistentry>
 225
 226       <varlistentry>
 227         <term><option>--send-sighup</option></term>
 228
 229         <listitem><para>When terminating the scope or service unit, send a SIGHUP immediately after SIGTERM. This is
 230         useful to indicate to shells and shell-like processes that the connection has been severed. Also see
 231         <varname>SendSIGHUP=</varname> in
 232         <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 233         </para>
 234
 235         <xi:include href="version-info.xml" xpointer="v207"/>
 236         </listitem>
 237       </varlistentry>
 238
 239       <varlistentry>
 240         <term><option>--service-type=</option></term>
 241
 242         <listitem><para>Sets the service type. Also see
 243         <varname>Type=</varname> in
 244         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>. This
 245         option has no effect in conjunction with
 246         <option>--scope</option>. Defaults to
 247         <constant>simple</constant>.</para>
 248
 249         <xi:include href="version-info.xml" xpointer="v211"/>
 250         </listitem>
 251       </varlistentry>
 252
 253       <varlistentry>
 254         <term><option>--uid=</option></term>
 255         <term><option>--gid=</option></term>
 256
 257         <listitem><para>Runs the service process under the specified UNIX user and group. Also see
 258         <varname>User=</varname> and <varname>Group=</varname> in
 259         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 260
 261         <xi:include href="version-info.xml" xpointer="v211"/>
 262         </listitem>
 263       </varlistentry>
 264
 265       <varlistentry>
 266         <term><option>--nice=</option></term>
 267
 268         <listitem><para>Runs the service process with the specified
 269         nice level. Also see <varname>Nice=</varname> in
 270         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 271
 272         <xi:include href="version-info.xml" xpointer="v211"/>
 273         </listitem>
 274       </varlistentry>
 275
 276       <varlistentry>
 277         <term><option>--working-directory=</option></term>
 278
 279         <listitem><para>Runs the service process with the specified working directory. Also see
 280         <varname>WorkingDirectory=</varname> in
 281         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 282
 283         <xi:include href="version-info.xml" xpointer="v240"/>
 284         </listitem>
 285       </varlistentry>
 286
 287       <varlistentry>
 288         <term><option>--same-dir</option></term>
 289         <term><option>-d</option></term>
 290
 291         <listitem><para>Similar to <option>--working-directory=</option>, but uses the current working
 292         directory of the caller for the service to execute.</para>
 293
 294         <xi:include href="version-info.xml" xpointer="v240"/></listitem>
 295       </varlistentry>
 296
 297       <varlistentry>
 298         <term><option>-E <replaceable>NAME</replaceable>[=<replaceable>VALUE</replaceable>]</option></term>
 299         <term><option>--setenv=<replaceable>NAME</replaceable>[=<replaceable>VALUE</replaceable>]</option></term>
 300
 301         <listitem><para>Runs the service process with the specified environment variable set. This parameter
 302         may be used more than once to set multiple variables. When <literal>=</literal> and
 303         <replaceable>VALUE</replaceable> are omitted, the value of the variable with the same name in the
 304         program environment will be used.</para>
 305
 306         <para>Also see <varname>Environment=</varname> in
 307         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 308
 309         <xi:include href="version-info.xml" xpointer="v250"/>
 310         </listitem>
 311       </varlistentry>
 312
 313       <varlistentry>
 314         <term><option>--pty</option></term>
 315         <term><option>-t</option></term>
 316
 317         <listitem><para>When invoking the command, the transient service connects its standard input, output and error
 318         to the terminal <command>systemd-run</command> is invoked on, via a pseudo TTY device. This allows running
 319         programs that expect interactive user input/output as services, such as interactive command shells.</para>
 320
 321         <para>Note that
 322         <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
 323         <command>shell</command> command is usually a better alternative for requesting a new, interactive login
 324         session on the local host or a local container.</para>
 325
 326         <para>See below for details on how this switch combines with <option>--pipe</option>.</para>
 327
 328         <xi:include href="version-info.xml" xpointer="v219"/></listitem>
 329       </varlistentry>
 330
 331       <varlistentry>
 332         <term><option>--pipe</option></term>
 333         <term><option>-P</option></term>
 334
 335         <listitem><para>If specified, standard input, output, and error of the transient service are inherited from the
 336         <command>systemd-run</command> command itself. This allows <command>systemd-run</command>
 337         to be used within shell pipelines.
 338         Note that this mode is not suitable for interactive command shells and similar, as the
 339         service process will not become a TTY controller when invoked on a terminal. Use <option>--pty</option> instead
 340         in that case.</para>
 341
 342         <para>When both <option>--pipe</option> and <option>--pty</option> are used in combination the more appropriate
 343         option is automatically determined and used. Specifically, when invoked with standard input, output and error
 344         connected to a TTY <option>--pty</option> is used, and otherwise <option>--pipe</option>.</para>
 345
 346         <para>When this option is used the original file descriptors <command>systemd-run</command> receives are passed
 347         to the service processes as-is. If the service runs with different privileges than
 348         <command>systemd-run</command>, this means the service might not be able to re-open the passed file
 349         descriptors, due to normal file descriptor access restrictions. If the invoked process is a shell script that
 350         uses the <command>echo "hello" >/dev/stderr</command> construct for writing messages to stderr, this might
 351         cause problems, as this only works if stderr can be re-opened. To mitigate this use the construct <command>echo
 352         "hello" >&amp;2</command> instead, which is mostly equivalent and avoids this pitfall.</para>
 353
 354         <xi:include href="version-info.xml" xpointer="v235"/></listitem>
 355       </varlistentry>
 356
 357       <varlistentry>
 358         <term><option>--shell</option></term>
 359         <term><option>-S</option></term>
 360
 361         <listitem><para>A shortcut for <literal>--pty --same-dir --wait --collect --service-type=exec $SHELL</literal>,
 362         i.e. requests an interactive shell in the current working directory, running in service context, accessible
 363         with a single switch.</para>
 364
 365         <xi:include href="version-info.xml" xpointer="v240"/></listitem>
 366       </varlistentry>
 367
 368       <varlistentry>
 369         <term><option>--quiet</option></term>
 370         <term><option>-q</option></term>
 371
 372         <listitem><para>Suppresses additional informational output
 373         while running. This is particularly useful in combination with
 374         <option>--pty</option> when it will suppress the initial
 375         message explaining how to terminate the TTY connection.</para>
 376
 377         <xi:include href="version-info.xml" xpointer="v219"/></listitem>
 378       </varlistentry>
 379
 380       <varlistentry>
 381         <term><option>--on-active=</option></term>
 382         <term><option>--on-boot=</option></term>
 383         <term><option>--on-startup=</option></term>
 384         <term><option>--on-unit-active=</option></term>
 385         <term><option>--on-unit-inactive=</option></term>
 386
 387         <listitem><para>Defines a monotonic timer relative to different starting points for starting the specified
 388         command. See <varname>OnActiveSec=</varname>, <varname>OnBootSec=</varname>, <varname>OnStartupSec=</varname>,
 389         <varname>OnUnitActiveSec=</varname> and <varname>OnUnitInactiveSec=</varname> in
 390         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
 391         details. These options are shortcuts for <command>--timer-property=</command> with the relevant properties.
 392         These options may not be combined with <option>--scope</option> or <option>--pty</option>.</para>
 393
 394         <xi:include href="version-info.xml" xpointer="v218"/>
 395         </listitem>
 396       </varlistentry>
 397
 398       <varlistentry>
 399         <term><option>--on-calendar=</option></term>
 400
 401         <listitem><para>Defines a calendar timer for starting the specified command. See <varname>OnCalendar=</varname>
 402         in <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>. This
 403         option is a shortcut for <command>--timer-property=OnCalendar=</command>. This option may not be combined with
 404         <option>--scope</option> or <option>--pty</option>.</para>
 405
 406         <xi:include href="version-info.xml" xpointer="v218"/>
 407         </listitem>
 408       </varlistentry>
 409
 410       <varlistentry>
 411         <term><option>--on-clock-change</option></term>
 412         <term><option>--on-timezone-change</option></term>
 413
 414         <listitem><para>Defines a trigger based on system clock jumps or timezone changes for starting the
 415         specified command. See <varname>OnClockChange=</varname> and <varname>OnTimezoneChange=</varname> in
 416         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>. These
 417         options are shortcuts for <command>--timer-property=OnClockChange=yes</command> and
 418         <command>--timer-property=OnTimezoneChange=yes</command>. These options may not be combined with
 419         <option>--scope</option> or <option>--pty</option>.</para>
 420
 421         <xi:include href="version-info.xml" xpointer="v242"/></listitem>
 422       </varlistentry>
 423
 424       <varlistentry>
 425         <term><option>--path-property=</option></term>
 426         <term><option>--socket-property=</option></term>
 427         <term><option>--timer-property=</option></term>
 428
 429         <listitem><para>Sets a property on the path, socket, or timer unit that is created. This option is
 430         similar to <option>--property=</option>, but applies to the transient path, socket, or timer unit
 431         rather than the transient service unit created. This option takes an assignment in the same format as
 432         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
 433         <command>set-property</command> command. These options may not be combined with
 434         <option>--scope</option> or <option>--pty</option>.</para>
 435         </listitem>
 436       </varlistentry>
 437
 438       <varlistentry>
 439         <term><option>--no-block</option></term>
 440
 441         <listitem>
 442           <para>Do not synchronously wait for the unit start operation to finish. If this option is not specified, the
 443           start request for the transient unit will be verified, enqueued and <command>systemd-run</command> will wait
 444           until the unit's start-up is completed. By passing this argument, it is only verified and enqueued. This
 445           option may not be combined with <option>--wait</option>.</para>
 446
 447           <xi:include href="version-info.xml" xpointer="v220"/>
 448         </listitem>
 449       </varlistentry>
 450
 451       <varlistentry>
 452         <term><option>--wait</option></term>
 453
 454         <listitem><para>Synchronously wait for the transient service to terminate. If this option is specified, the
 455         start request for the transient unit is verified, enqueued, and waited for. Subsequently the invoked unit is
 456         monitored, and it is waited until it is deactivated again (most likely because the specified command
 457         completed). On exit, terse information about the unit's runtime is shown, including total runtime (as well as
 458         CPU usage, if <option>--property=CPUAccounting=1</option> was set) and the exit code and status of the main
 459         process. This output may be suppressed with <option>--quiet</option>. This option may not be combined with
 460         <option>--no-block</option>, <option>--scope</option> or the various path, socket, or timer options.</para>
 461
 462         <xi:include href="version-info.xml" xpointer="v232"/></listitem>
 463       </varlistentry>
 464
 465       <varlistentry>
 466         <term><option>-G</option></term>
 467         <term><option>--collect</option></term>
 468
 469         <listitem><para>Unload the transient unit after it completed, even if it failed. Normally, without this option,
 470         all units that ran and failed are kept in memory until the user explicitly resets their failure state with
 471         <command>systemctl reset-failed</command> or an equivalent command. On the other hand, units that ran
 472         successfully are unloaded immediately. If this option is turned on the "garbage collection" of units is more
 473         aggressive, and unloads units regardless if they exited successfully or failed. This option is a shortcut for
 474         <command>--property=CollectMode=inactive-or-failed</command>, see the explanation for
 475         <varname>CollectMode=</varname> in
 476         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for further
 477         information.</para>
 478
 479         <xi:include href="version-info.xml" xpointer="v236"/></listitem>
 480       </varlistentry>
 481
 482       <xi:include href="user-system-options.xml" xpointer="user" />
 483       <xi:include href="user-system-options.xml" xpointer="system" />
 484       <xi:include href="user-system-options.xml" xpointer="host" />
 485       <xi:include href="user-system-options.xml" xpointer="machine" />
 486
 487       <xi:include href="standard-options.xml" xpointer="help" />
 488       <xi:include href="standard-options.xml" xpointer="version" />
 489     </variablelist>
 490
 491     <para>All command line arguments after the first non-option argument become part of the command line of
 492     the launched process.</para>
 493   </refsect1>
 494
 495   <refsect1>
 496     <title>Exit status</title>
 497
 498     <para>On success, 0 is returned. If <command>systemd-run</command> failed to start the service, a
 499     non-zero return value will be returned. If <command>systemd-run</command> waits for the service to
 500     terminate, the return value will be propagated from the service. 0 will be returned on success, including
 501     all the cases where systemd considers a service to have exited cleanly, see the discussion of
 502     <varname>SuccessExitStatus=</varname> in
 503     <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 504     </para>
 505   </refsect1>
 506
 507   <refsect1>
 508     <title>Examples</title>
 509
 510     <example>
 511       <title>Logging environment variables provided by systemd to services</title>
 512
 513       <programlisting># systemd-run env
 514 Running as unit: run-19945.service
 515 # journalctl -u run-19945.service
 516 Sep 08 07:37:21 bupkis systemd[1]: Starting /usr/bin/env...
 517 Sep 08 07:37:21 bupkis systemd[1]: Started /usr/bin/env.
 518 Sep 08 07:37:21 bupkis env[19948]: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
 519 Sep 08 07:37:21 bupkis env[19948]: LANG=en_US.UTF-8
 520 Sep 08 07:37:21 bupkis env[19948]: BOOT_IMAGE=/vmlinuz-3.11.0-0.rc5.git6.2.fc20.x86_64</programlisting>
 521     </example>
 522
 523     <example>
 524       <title>Limiting resources available to a command</title>
 525
 526       <programlisting># systemd-run -p IOWeight=10 updatedb</programlisting>
 527
 528       <para>This command invokes the <citerefentry
 529       project='man-pages'><refentrytitle>updatedb</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 530       tool, but lowers the block I/O weight for it to 10. See
 531       <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 532       for more information on the <varname>IOWeight=</varname> property.</para>
 533     </example>
 534
 535     <example>
 536       <title>Running commands at a specified time</title>
 537
 538       <para>The following command will touch a file after 30 seconds.</para>
 539
 540       <programlisting># date; systemd-run --on-active=30 --timer-property=AccuracySec=100ms /bin/touch /tmp/foo
 541 Mon Dec  8 20:44:24 KST 2014
 542 Running as unit: run-71.timer
 543 Will run service as unit: run-71.service
 544 # journalctl -b -u run-71.timer
 545 -- Journal begins at Fri 2014-12-05 19:09:21 KST, ends at Mon 2014-12-08 20:44:54 KST. --
 546 Dec 08 20:44:38 container systemd[1]: Starting /bin/touch /tmp/foo.
 547 Dec 08 20:44:38 container systemd[1]: Started /bin/touch /tmp/foo.
 548 # journalctl -b -u run-71.service
 549 -- Journal begins at Fri 2014-12-05 19:09:21 KST, ends at Mon 2014-12-08 20:44:54 KST. --
 550 Dec 08 20:44:48 container systemd[1]: Starting /bin/touch /tmp/foo...
 551 Dec 08 20:44:48 container systemd[1]: Started /bin/touch /tmp/foo.</programlisting>
 552     </example>
 553
 554     <example>
 555       <title>Allowing access to the tty</title>
 556
 557       <para>The following command invokes <citerefentry project='man-pages'><refentrytitle>bash</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 558       as a service passing its standard input, output and error to the calling TTY.</para>
 559
 560       <programlisting># systemd-run -t --send-sighup bash</programlisting>
 561     </example>
 562
 563     <example>
 564       <title>Start <command>screen</command> as a user service</title>
 565
 566       <programlisting>$ systemd-run --scope --user screen
 567 Running scope as unit run-r14b0047ab6df45bfb45e7786cc839e76.scope.
 568
 569 $ screen -ls
 570 There is a screen on:
 571         492..laptop     (Detached)
 572 1 Socket in /var/run/screen/S-fatima.
 573 </programlisting>
 574
 575       <para>This starts the <command>screen</command> process as a child of the
 576       <command>systemd --user</command> process that was started by
 577       <filename>user@.service</filename>, in a scope unit. A
 578       <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 579       unit is used instead of a
 580       <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 581       unit, because <command>screen</command> will exit when detaching from the terminal,
 582       and a service unit would be terminated. Running <command>screen</command>
 583       as a user unit has the advantage that it is not part of the session scope.
 584       If <varname>KillUserProcesses=yes</varname> is configured in
 585       <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 586       the default, the session scope will be terminated when the user logs
 587       out of that session.</para>
 588
 589       <para>The <filename>user@.service</filename> is started automatically
 590       when the user first logs in, and stays around as long as at least one
 591       login session is open. After the user logs out of the last session,
 592       <filename>user@.service</filename> and all services underneath it
 593       are terminated. This behavior is the default, when "lingering" is
 594       not enabled for that user. Enabling lingering means that
 595       <filename>user@.service</filename> is started automatically during
 596       boot, even if the user is not logged in, and that the service is
 597       not terminated when the user logs out.</para>
 598
 599       <para>Enabling lingering allows the user to run processes without being logged in,
 600       for example to allow <command>screen</command> to persist after the user logs out,
 601       even if the session scope is terminated. In the default configuration, users can
 602       enable lingering for themselves:</para>
 603
 604       <programlisting>$ loginctl enable-linger</programlisting>
 605     </example>
 606
 607     <example>
 608       <title>Variable expansion by the manager</title>
 609
 610       <programlisting>$ systemd-run -t echo "&lt;${INVOCATION_ID}>" '&lt;${INVOCATION_ID}>'
 611       &lt;> &lt;5d0149bfa2c34b79bccb13074001eb20>
 612       </programlisting>
 613
 614       <para>The first argument is expanded by the shell (double quotes), but the second one is not expanded
 615       by the shell (single quotes). <command>echo</command> is called with [<literal>/usr/bin/echo</literal>,
 616       <literal>[]</literal>, <literal>[${INVOCATION_ID}]</literal>] as the argument array, and then
 617       <command>systemd</command> generates <varname>${INVOCATION_ID}</varname> and substitutes it in the
 618       command-line. This substitution could not be done on the client side, because the target ID that will
 619       be set for the service isn't known before the call is made.</para>
 620     </example>
 621
 622     <example>
 623       <title>Variable expansion and output redirection using a shell</title>
 624
 625       <para>Variable expansion by <command>systemd</command> can be disabled with
 626       <varname>--expand-environment=no</varname>.</para>
 627
 628       <para>Disabling variable expansion can be useful if the command to execute contains dollar characters
 629       and escaping them would be inconvenient. For example, when a shell is used:</para>
 630
 631       <programlisting>$ systemd-run --expand-environment=no -t bash \
 632       -c 'echo $SHELL $$ >/dev/stdout'
 633 /bin/bash 12345
 634       </programlisting>
 635
 636       <para>The last argument is passed verbatim to the <command>bash</command> shell which is started by the
 637       service unit. The shell expands <literal>$SHELL</literal> to the path of the shell, and
 638       <literal>$$</literal> to its process number, and then those strings are passed to the
 639       <command>echo</command> built-in and printed to standard output (which in this case is connected to the
 640       calling terminal).</para>
 641     </example>
 642
 643     <example>
 644       <title>Return value</title>
 645
 646       <programlisting>$ systemd-run --user --wait true
 647 $ systemd-run --user --wait -p SuccessExitStatus=11 bash -c 'exit 11'
 648 $ systemd-run --user --wait -p SuccessExitStatus=SIGUSR1 --expand-environment=no \
 649       bash -c 'kill -SIGUSR1 $$'</programlisting>
 650
 651       <para>Those three invocations will succeed, i.e. terminate with an exit code of 0.</para>
 652     </example>
 653   </refsect1>
 654
 655   <refsect1>
 656     <title>See Also</title>
 657     <para>
 658       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 659       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 660       <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 661       <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 662       <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 663       <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 664       <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 665       <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 666       <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 667       <citerefentry><refentrytitle>systemd-mount</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 668       <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 669     </para>
 670   </refsect1>
 671
 672 </refentry>