man/systemctl.xml

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   8 Copyright 2010 Lennart Poettering
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  23
  24 <refentry id="systemctl">
  25
  26   <refentryinfo>
  27     <title>systemctl</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>systemctl</refentrytitle>
  42     <manvolnum>1</manvolnum>
  43   </refmeta>
  44
  45   <refnamediv>
  46     <refname>systemctl</refname>
  47     <refpurpose>Control the systemd system and service manager</refpurpose>
  48   </refnamediv>
  49
  50   <refsynopsisdiv>
  51     <cmdsynopsis>
  52       <command>systemctl</command>
  53       <arg choice="opt" rep="repeat">OPTIONS</arg>
  54       <arg choice="plain">COMMAND</arg>
  55       <arg choice="opt" rep="repeat">NAME</arg>
  56     </cmdsynopsis>
  57   </refsynopsisdiv>
  58
  59   <refsect1>
  60     <title>Description</title>
  61
  62     <para><command>systemctl</command> may be used to
  63     introspect and control the state of the
  64     <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  65     system and service manager.</para>
  66   </refsect1>
  67
  68   <refsect1>
  69     <title>Options</title>
  70
  71     <para>The following options are understood:</para>
  72
  73     <variablelist>
  74       <varlistentry>
  75         <term><option>-h</option></term>
  76         <term><option>--help</option></term>
  77
  78         <listitem><para>Prints a short help
  79         text and exits.</para></listitem>
  80       </varlistentry>
  81
  82       <varlistentry>
  83         <term><option>--version</option></term>
  84
  85         <listitem>
  86           <para>Prints a short version string and exits.</para>
  87         </listitem>
  88       </varlistentry>
  89
  90       <varlistentry>
  91         <term><option>-t</option></term>
  92         <term><option>--type=</option></term>
  93
  94         <listitem>
  95           <para>The argument should be a unit type name such as
  96           <option>service</option> and <option>socket</option>, or a
  97           unit load state such as <option>loaded</option> and
  98           <option>masked</option>.
  99           </para>
 100
 101           <para>If the argument is a unit type, when listing units,
 102           limit display to certain unit types. If not specified units
 103           of all types will be shown.</para>
 104
 105           <para>If the argument is a unit load state, when listing
 106           units, limit display to certain unit types. If not specified
 107           units of in all load states will be shown.</para>
 108
 109           <para>As a special case, if the argument is
 110           <option>help</option>, a list of allowed values will be
 111           printed and the program will exit.</para>
 112         </listitem>
 113       </varlistentry>
 114
 115       <varlistentry>
 116         <term><option>-p</option></term>
 117         <term><option>--property=</option></term>
 118
 119         <listitem>
 120           <para>When showing unit/job/manager properties with the
 121           <command>show</command> command, limit display to certain
 122           properties as specified as argument. If not specified all
 123           set properties are shown. The argument should be a
 124           comma-seperated list of property names, such as
 125           <literal>MainPID</literal>. If specified more than once all
 126           properties with the specified names are shown.</para>
 127         </listitem>
 128       </varlistentry>
 129
 130       <varlistentry>
 131         <term><option>-a</option></term>
 132         <term><option>--all</option></term>
 133
 134         <listitem>
 135           <para>When listing units, show all units, regardless of
 136           their state, including inactive units. When showing
 137           unit/job/manager properties, show all properties regardless
 138           whether they are set or not.</para>
 139         </listitem>
 140       </varlistentry>
 141
 142       <varlistentry>
 143         <term><option>--failed</option></term>
 144
 145         <listitem>
 146           <para>When listing units, show only failed units. Do not
 147           confuse with <option>--fail</option>.</para>
 148         </listitem>
 149       </varlistentry>
 150
 151       <varlistentry>
 152         <term><option>--full</option></term>
 153
 154         <listitem>
 155           <para>Do not ellipsize unit names, cgroup members, and
 156           truncate unit descriptions in the output of
 157           <command>list-units</command> and
 158           <command>list-jobs</command>.</para>
 159         </listitem>
 160       </varlistentry>
 161
 162       <varlistentry>
 163         <term><option>--fail</option></term>
 164
 165         <listitem>
 166           <para>If the requested operation conflicts with a pending
 167           unfinished job, fail the command. If this is not specified
 168           the requested operation will replace the pending job, if
 169           necessary. Do not confuse with
 170           <option>--failed</option>.</para>
 171         </listitem>
 172       </varlistentry>
 173
 174       <varlistentry>
 175         <term><option>--irreversible</option></term>
 176
 177         <listitem>
 178           <para>Mark this transaction's jobs as irreversible. This prevents
 179           future conflicting transactions from replacing these jobs.
 180           The jobs can still be cancelled using the <command>cancel</command>
 181           command.</para>
 182         </listitem>
 183       </varlistentry>
 184
 185       <varlistentry>
 186         <term><option>--ignore-dependencies</option></term>
 187
 188         <listitem>
 189           <para>When enqueuing a new job ignore all its dependencies
 190           and execute it immediately. If passed no required units of
 191           the unit passed will be pulled in, and no ordering
 192           dependencies will be honored. This is mostly a debugging and
 193           rescue tool for the administrator and should not be used by
 194           applications.</para>
 195         </listitem>
 196       </varlistentry>
 197
 198       <varlistentry>
 199         <term><option>-i</option></term>
 200         <term><option>--ignore-inhibitors</option></term>
 201
 202         <listitem>
 203           <para>When system shutdown or a sleep state is requested,
 204           ignore inhibitor locks. Applications can establish inhibitor
 205           locks to avoid that certain important operations (such as CD
 206           burning or suchlike) are interrupted by system shutdown or a
 207           sleep state. Any user may take these locks and privileged
 208           users may override these locks. If any locks are taken,
 209           shutdown and sleep state requests will normally fail
 210           (regardless if privileged or not) and a list of active locks
 211           is printed. However if <option>--ignore-inhibitors</option>
 212           is specified the locks are ignored and not printed, and the
 213           operation attempted anyway, possibly requiring additional
 214           privileges.</para>
 215         </listitem>
 216       </varlistentry>
 217
 218       <varlistentry>
 219         <term><option>-q</option></term>
 220         <term><option>--quiet</option></term>
 221
 222         <listitem>
 223           <para>Suppress output to standard output in
 224           <command>snapshot</command>,
 225           <command>is-active</command>,
 226           <command>is-failed</command>,
 227           <command>enable</command> and
 228         <command>disable</command>.</para>
 229         </listitem>
 230       </varlistentry>
 231
 232       <varlistentry>
 233         <term><option>--no-block</option></term>
 234
 235         <listitem>
 236           <para>Do not synchronously wait for the requested operation
 237           to finish. If this is not specified the job will be
 238           verified, enqueued and <command>systemctl</command> will
 239           wait until it is completed. By passing this argument it is
 240           only verified and enqueued.</para>
 241         </listitem>
 242       </varlistentry>
 243
 244       <varlistentry>
 245         <term><option>--no-legend</option></term>
 246
 247         <listitem>
 248           <para>Do not print a legend, i.e.  the column headers and
 249           the footer with hints.</para>
 250         </listitem>
 251       </varlistentry>
 252
 253       <varlistentry>
 254         <term><option>--no-pager</option></term>
 255
 256         <listitem>
 257           <para>Do not pipe output into a pager.</para>
 258         </listitem>
 259       </varlistentry>
 260
 261       <varlistentry>
 262         <term><option>--system</option></term>
 263
 264         <listitem>
 265           <para>Talk to the systemd system manager. (Default)</para>
 266         </listitem>
 267       </varlistentry>
 268
 269       <varlistentry>
 270         <term><option>--user</option></term>
 271
 272         <listitem>
 273           <para>Talk to the systemd manager of the calling
 274           user.</para>
 275         </listitem>
 276       </varlistentry>
 277
 278       <varlistentry>
 279         <term><option>--no-wall</option></term>
 280
 281         <listitem>
 282           <para>Don't send wall message before halt, power-off,
 283           reboot.</para>
 284         </listitem>
 285       </varlistentry>
 286
 287       <varlistentry>
 288         <term><option>--global</option></term>
 289
 290         <listitem>
 291           <para>When used with <command>enable</command> and
 292           <command>disable</command>, operate on the global user
 293           configuration directory, thus enabling or disabling a unit
 294           file globally for all future logins of all users.</para>
 295         </listitem>
 296       </varlistentry>
 297
 298       <varlistentry>
 299         <term><option>--no-reload</option></term>
 300
 301         <listitem>
 302           <para>When used with <command>enable</command> and
 303           <command>disable</command>, do not implicitly reload daemon
 304           configuration after executing the changes.</para>
 305         </listitem>
 306       </varlistentry>
 307
 308       <varlistentry>
 309         <term><option>--no-ask-password</option></term>
 310
 311         <listitem>
 312           <para>When used with <command>start</command> and related
 313           commands, disables asking for passwords. Background services
 314           may require input of a password or passphrase string, for
 315           example to unlock system hard disks or cryptographic
 316           certificates. Unless this option is specified and the
 317           command is invoked from a terminal
 318           <command>systemctl</command> will query the user on the
 319           terminal for the necessary secrets. Use this option to
 320           switch this behavior off. In this case the password must be
 321           supplied by some other means (for example graphical password
 322           agents) or the service might fail. This also disables
 323           querying the user for authentication for privileged
 324           operations.</para>
 325         </listitem>
 326
 327       </varlistentry>
 328
 329       <varlistentry>
 330         <term><option>--kill-who=</option></term>
 331
 332         <listitem>
 333           <para>When used with <command>kill</command>, choose which
 334           processes to kill. Must be one of <option>main</option>,
 335           <option>control</option> or <option>all</option> to select
 336           whether to kill only the main process of the unit, the
 337           control process or all processes of the unit. If omitted
 338           defaults to <option>all</option>.</para>
 339         </listitem>
 340
 341       </varlistentry>
 342
 343       <varlistentry>
 344         <term><option>-s</option></term>
 345         <term><option>--signal=</option></term>
 346
 347         <listitem>
 348           <para>When used with <command>kill</command>, choose which
 349           signal to send to selected processes. Must be one of the
 350           well known signal specifiers such as SIGTERM, SIGINT or
 351           SIGSTOP. If omitted defaults to
 352           <option>SIGTERM</option>.</para>
 353         </listitem>
 354       </varlistentry>
 355
 356       <varlistentry>
 357         <term><option>-f</option></term>
 358         <term><option>--force</option></term>
 359
 360         <listitem>
 361           <para>When used with <command>enable</command>, overwrite
 362           any existing conflicting symlinks.</para>
 363
 364           <para>When used with <command>halt</command>,
 365           <command>poweroff</command>, <command>reboot</command> or
 366           <command>kexec</command> execute the selected operation
 367           without shutting down all units. However, all processes will
 368           be killed forcibly and all file systems are unmounted or
 369           remounted read-only. This is hence a drastic but relatively
 370           safe option to request an immediate reboot. If
 371           <option>--force</option> is specified twice for these
 372           operations, they will be executed immediately without
 373           terminating any processes or umounting any file
 374           systems. Warning: specifying <option>--force</option> twice
 375           with any of these operations might result in data
 376           loss.</para>
 377         </listitem>
 378       </varlistentry>
 379
 380       <varlistentry>
 381         <term><option>--root=</option></term>
 382
 383         <listitem>
 384           <para>When used with
 385           <command>enable</command>/<command>disable</command>/<command>is-enabled</command>
 386           (and related commands), use alternative root path when
 387           looking for unit files.</para>
 388         </listitem>
 389
 390       </varlistentry>
 391
 392       <varlistentry>
 393         <term><option>--runtime</option></term>
 394
 395         <listitem>
 396           <para>When used with <command>enable</command>,
 397           <command>disable</command>, <command>is-enabled</command>
 398           (and related commands), make changes only temporarily, so
 399           that they are lost on the next reboot. This will have the
 400           effect that changes are not made in subdirectories of
 401           <filename>/etc</filename> but in <filename>/run</filename>,
 402           with identical immediate effects, however, since the latter
 403           is lost on reboot, the changes are lost too.</para>
 404
 405           <para>Similar, when used with
 406           <command>set-cgroup-attr</command>,
 407           <command>unset-cgroup-attr</command>,
 408           <command>set-cgroup</command> and
 409           <command>unset-cgroup</command>, make changes only
 410           temporarily, so that they are lost on the next
 411           reboot.</para>
 412         </listitem>
 413       </varlistentry>
 414
 415       <varlistentry>
 416         <term><option>-H</option></term>
 417         <term><option>--host</option></term>
 418
 419         <listitem>
 420           <para>Execute operation remotely. Specify a hostname, or
 421           username and hostname separated by @, to connect to. This
 422           will use SSH to talk to the remote systemd
 423           instance.</para>
 424         </listitem>
 425       </varlistentry>
 426
 427       <varlistentry>
 428         <term><option>-P</option></term>
 429         <term><option>--privileged</option></term>
 430
 431         <listitem>
 432           <para>Acquire privileges via PolicyKit before executing the
 433           operation.</para>
 434         </listitem>
 435       </varlistentry>
 436
 437       <varlistentry>
 438         <term><option>-n</option></term>
 439         <term><option>--lines=</option></term>
 440
 441         <listitem>
 442           <para>When used with <command>status</command> controls the
 443           number of journal lines to show, counting from the most
 444           recent ones. Takes a positive integer argument. Defaults to
 445           10.</para>
 446         </listitem>
 447       </varlistentry>
 448
 449       <varlistentry>
 450         <term><option>-o</option></term>
 451         <term><option>--output=</option></term>
 452
 453         <listitem>
 454           <para>When used with <command>status</command> controls the
 455           formatting of the journal entries that are shown. For the
 456           available choices see
 457           <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
 458           Defaults to <literal>short</literal>.</para>
 459         </listitem>
 460       </varlistentry>
 461
 462     </variablelist>
 463   </refsect1>
 464
 465   <refsect1>
 466     <title>Commands</title>
 467
 468     <para>The following commands are understood:</para>
 469
 470     <variablelist>
 471       <varlistentry>
 472         <term><command>list-units</command></term>
 473
 474         <listitem>
 475           <para>List known units (subject to limitations specified
 476           with <option>-t</option>).</para>
 477
 478           <para>This is the default command.</para>
 479         </listitem>
 480       </varlistentry>
 481       <varlistentry>
 482         <term><command>start <replaceable>NAME</replaceable>...</command></term>
 483
 484         <listitem>
 485           <para>Start (activate) one or more units specified on the
 486           command line.</para>
 487         </listitem>
 488       </varlistentry>
 489       <varlistentry>
 490         <term><command>stop <replaceable>NAME</replaceable>...</command></term>
 491
 492         <listitem>
 493           <para>Stop (deactivate) one or more units specified on the
 494           command line.</para>
 495         </listitem>
 496       </varlistentry>
 497       <varlistentry>
 498         <term><command>reload <replaceable>NAME</replaceable>...</command></term>
 499
 500         <listitem>
 501           <para>Asks all units listed on the command line to reload
 502           their configuration. Note that this will reload the
 503           service-specific configuration, not the unit configuration
 504           file of systemd. If you want systemd to reload the
 505           configuration file of a unit use the
 506           <command>daemon-reload</command> command. In other words:
 507           for the example case of Apache, this will reload Apache's
 508           <filename>httpd.conf</filename> in the web server, not the
 509           <filename>apache.service</filename> systemd unit
 510           file. </para>
 511
 512           <para>This command should not be confused with the
 513           <command>daemon-reload</command> or <command>load</command>
 514           commands.</para>
 515         </listitem>
 516
 517       </varlistentry>
 518       <varlistentry>
 519         <term><command>restart <replaceable>NAME</replaceable>...</command></term>
 520
 521         <listitem>
 522           <para>Restart one or more units specified on the command
 523           line. If the units are not running yet they will be
 524           started.</para>
 525         </listitem>
 526       </varlistentry>
 527       <varlistentry>
 528         <term><command>try-restart <replaceable>NAME</replaceable>...</command></term>
 529
 530         <listitem>
 531           <para>Restart one or more units specified on the command
 532           line if the units are running. Do nothing if units are not
 533           running.  Note that for compatibility with Red Hat init
 534           scripts <command>condrestart</command> is equivalent to this
 535           command.</para>
 536         </listitem>
 537       </varlistentry>
 538       <varlistentry>
 539         <term><command>reload-or-restart <replaceable>NAME</replaceable>...</command></term>
 540
 541         <listitem>
 542           <para>Reload one or more units if they support it. If not,
 543           restart them instead. If the units are not running yet they
 544           will be started.</para>
 545         </listitem>
 546       </varlistentry>
 547       <varlistentry>
 548         <term><command>reload-or-try-restart <replaceable>NAME</replaceable>...</command></term>
 549
 550         <listitem>
 551           <para>Reload one or more units if they support it. If not,
 552           restart them instead. Do nothing if the units are not
 553           running. Note that for compatibility with SysV init scripts
 554           <command>force-reload</command> is equivalent to this
 555           command.</para>
 556         </listitem>
 557       </varlistentry>
 558       <varlistentry>
 559         <term><command>isolate <replaceable>NAME</replaceable></command></term>
 560
 561         <listitem>
 562           <para>Start the unit specified on the command line and its
 563           dependencies and stop all others.</para>
 564
 565           <para>This is similar to changing the runlevel in a
 566           traditional init system. The <command>isolate</command>
 567           command will immediately stop processes that are not enabled
 568           in the new unit, possibly including the graphical
 569           environment or terminal you are currently using.</para>
 570
 571           <para>Note that this is allowed only on units where
 572           <option>AllowIsolate=</option> is enabled. See
 573           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 574           for details.</para>
 575         </listitem>
 576       </varlistentry>
 577       <varlistentry>
 578         <term><command>kill <replaceable>NAME</replaceable>...</command></term>
 579
 580         <listitem>
 581           <para>Send a signal to one or more processes of the
 582           unit. Use <option>--kill-who=</option> to select which
 583           process to kill. Use <option>--kill-mode=</option> to select
 584           the kill mode and <option>--signal=</option> to select the
 585           signal to send.</para>
 586         </listitem>
 587       </varlistentry>
 588       <varlistentry>
 589         <term><command>is-active <replaceable>NAME</replaceable>...</command></term>
 590
 591         <listitem>
 592           <para>Check whether any of the specified units are active
 593           (i.e. running). Returns an exit code 0 if at least one is
 594           active, non-zero otherwise. Unless <option>--quiet</option>
 595           is specified this will also print the current unit state to
 596           STDOUT.</para>
 597         </listitem>
 598       </varlistentry>
 599       <varlistentry>
 600         <term><command>is-failed <replaceable>NAME</replaceable>...</command></term>
 601
 602         <listitem>
 603           <para>Check whether any of the specified units are failed.
 604           Returns an exit code 0 if at least one is failed, non-zero
 605           otherwise. Unless <option>--quiet</option> is specified this
 606           will also print the current unit state to
 607           STDOUT.</para>
 608         </listitem>
 609       </varlistentry>
 610       <varlistentry>
 611         <term><command>status [<replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...]</command></term>
 612
 613         <listitem>
 614           <para>Show terse runtime status information about one or
 615           more units, followed by most recent log data from the
 616           journal. If no units are specified, show all units (subject
 617           to limitations specified with <option>-t</option>). If a PID
 618           is passed show information about the unit the process
 619           belongs to.</para>
 620
 621           <para>This function is intended to generate human-readable
 622           output. If you are looking for computer-parsable output, use
 623           <command>show</command> instead.</para>
 624         </listitem>
 625       </varlistentry>
 626       <varlistentry>
 627         <term><command>show [<replaceable>NAME</replaceable>...|<replaceable>JOB</replaceable>...]</command></term>
 628
 629         <listitem>
 630           <para>Show properties of one or more units, jobs, or the
 631           manager itself. If no argument is specified properties of
 632           the manager will be shown. If a unit name is specified
 633           properties of the unit is shown, and if a job id is
 634           specified properties of the job is shown. By default, empty
 635           properties are suppressed. Use <option>--all</option> to
 636           show those too. To select specific properties to show use
 637           <option>--property=</option>. This command is intended to be
 638           used whenever computer-parsable output is required. Use
 639           <command>status</command> if you are looking for formatted
 640           human-readable output.</para>
 641         </listitem>
 642       </varlistentry>
 643
 644       <varlistentry>
 645         <term><command>get-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable>...</command></term>
 646
 647         <listitem>
 648           <para>Retrieve the specified control group attributes of the
 649           specified unit. Takes a unit name and one or more attribute
 650           names such as <literal>cpu.shares</literal>. This will
 651           output the current values of the specified attributes,
 652           separated by new-lines. For attributes that take list of
 653           items the output will be new-line separated, too. This
 654           operation will always try to retrieve the data in question
 655           from the kernel first, and if that is not available use the
 656           configured values instead. Instead of low-level control
 657           group attribute names high-level pretty names may be used,
 658           as used for unit execution environment configuration, see
 659           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 660           for details. For example, passing
 661           <literal>memory.limit_in_bytes</literal> and
 662           <literal>MemoryLimit</literal> is equivalent.</para>
 663         </listitem>
 664       </varlistentry>
 665
 666       <varlistentry>
 667         <term><command>set-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable> <replaceable>VALUE</replaceable>...</command></term>
 668
 669         <listitem>
 670           <para>Set the specified control group attribute of the
 671           specified unit to the specified value. Takes a unit
 672           name and an attribute name such as
 673           <literal>cpu.shares</literal>, plus one or more values
 674           (multiple values may only be used for attributes that take
 675           multiple values). This operation will immediately update the
 676           kernel attribute for this unit and persistently store this
 677           setting for later reboots (unless <option>--runtime</option>
 678           is passed, in which case the setting is not saved
 679           persistently and only valid until the next reboot.) Instead
 680           of low-level control group attribute names high-level pretty
 681           names may be used, as used for unit execution environment
 682           configuration, see
 683           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 684           for details. For example, passing
 685           <literal>memory.limit_in_bytes</literal> and
 686           <literal>MemoryLimit</literal> is equivalent. This operation
 687           will implicitly create a control group for the unit in the
 688           controller the attribute belongs to, if needed. For
 689           attributes that take multiple values, this operation will
 690           append the specified values to the previously set values
 691           list (use <command>unset-cgroup-attr</command> to reset the
 692           list explicitly). For attributes that take a single value
 693           only the list will be reset implicitly.</para>
 694         </listitem>
 695       </varlistentry>
 696
 697       <varlistentry>
 698         <term><command>unset-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable>...</command></term>
 699
 700         <listitem><para>Unset the specified control group attributes
 701         of the specified unit. Takes a unit name and one or more
 702         attribut names such as <literal>cpu.shares</literal>. This
 703         operation might or might not have an immediate effect on the
 704         current kernel attribute value. This will remove any
 705         persistently stored configuration values for this attribute
 706         (as set with <command>set-cgroup-attr</command> before),
 707         unless <option>--runtime</option> is passed, in which case the
 708         configuration is reset only until the next reboot. Again,
 709         high-level control group attributes may be used instead of the
 710         low-level kernel ones. For attributes which take multiple
 711         values, all currently set values are reset.</para>
 712         </listitem>
 713       </varlistentry>
 714
 715       <varlistentry>
 716         <term><command>set-cgroup <replaceable>NAME</replaceable> <replaceable>CGROUP</replaceable>...</command></term>
 717         <term><command>unset-cgroup <replaceable>NAME</replaceable> <replaceable>CGROUP</replaceable>...</command></term>
 718
 719         <listitem><para>Add or remove a unit to/from a specific
 720         control group hierarchy and/or control group path. Takes a
 721         unit name, plus a control group specification in the syntax
 722         <replaceable>CONTROLLER</replaceable>:<replaceable>PATH</replaceable>
 723         or <replaceable>CONTROLLER</replaceable>. In the latter syntax
 724         (where the path is ommitted) the default unit control group
 725         path is implied. Examples: <literal>cpu</literal> or
 726         <literal>cpu:/foo/bar</literal>. If a unit is removed from a
 727         control group hierarchy all its processes will be moved to the
 728         root group of the hierarchy and all control group attributes
 729         will be reset. These operations are immediately reflected in
 730         the kernel hierarchy, and stored persistently to disk (unless
 731         <option>--runtime</option> is passed).</para>
 732         </listitem>
 733       </varlistentry>
 734
 735       <varlistentry>
 736         <term><command>help <replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...</command></term>
 737
 738         <listitem>
 739           <para>Show manual pages for one or more units, if
 740           available. If a PID is passed the manual pages for the unit
 741           the process of the PID belongs to is
 742           shown.</para>
 743         </listitem>
 744       </varlistentry>
 745
 746       <varlistentry>
 747         <term><command>reset-failed [<replaceable>NAME</replaceable>...]</command></term>
 748
 749         <listitem>
 750           <para>Reset the <literal>failed</literal> state of the
 751           specified units, or if no unit name is passed of all
 752           units. When a unit fails in some way (i.e. process exiting
 753           with non-zero error code, terminating abnormally or timing
 754           out) it will automatically enter the
 755           <literal>failed</literal> state and its exit code and status
 756           is recorded for introspection by the administrator until the
 757           service is restarted or reset with this command.</para>
 758         </listitem>
 759       </varlistentry>
 760
 761       <varlistentry>
 762         <term><command>list-unit-files</command></term>
 763
 764         <listitem>
 765           <para>List installed unit files.</para>
 766         </listitem>
 767       </varlistentry>
 768
 769       <varlistentry>
 770         <term><command>enable <replaceable>NAME</replaceable>...</command></term>
 771
 772         <listitem>
 773           <para>Enable one or more unit files or unit file instances,
 774           as specified on the command line. This will create a number
 775           of symlinks as encoded in the <literal>[Install]</literal>
 776           sections of the unit files. After the symlinks have been
 777           created the systemd configuration is reloaded (in a way that
 778           is equivalent to <command>daemon-reload</command>) to ensure
 779           the changes are taken into account immediately. Note that
 780           this does not have the effect that any of the units enabled
 781           are also started at the same time. If this is desired a
 782           separate <command>start</command> command must be invoked
 783           for the unit. Also note that in case of instance enablement,
 784           symlinks named same as instances are created in install
 785           location, however they all point to the same template unit
 786           file.</para>
 787
 788           <para>This command will print the actions executed. This
 789           output may be suppressed by passing <option>--quiet</option>.
 790           </para>
 791
 792           <para>Note that this operation creates only the suggested
 793           symlinks for the units. While this command is the
 794           recommended way to manipulate the unit configuration
 795           directory, the administrator is free to make additional
 796           changes manually, by placing or removing symlinks in the
 797           directory. This is particularly useful to create
 798           configurations that deviate from the suggested default
 799           installation. In this case the administrator must make sure
 800           to invoke <command>daemon-reload</command> manually as
 801           necessary, to ensure his changes are taken into account.
 802           </para>
 803
 804           <para>Enabling units should not be confused with starting
 805           (activating) units, as done by the <command>start</command>
 806           command. Enabling and starting units is orthogonal: units
 807           may be enabled without being started and started without
 808           being enabled. Enabling simply hooks the unit into various
 809           suggested places (for example, so that the unit is
 810           automatically started on boot or when a particular kind of
 811           hardware is plugged in). Starting actually spawns the daemon
 812           process (in case of service units), or binds the socket (in
 813           case of socket units), and so on.</para>
 814
 815           <para>Depending on whether <option>--system</option>,
 816           <option>--user</option> or <option>--global</option> is
 817           specified this enables the unit for the system, for the
 818           calling user only or for all future logins of all
 819           users. Note that in the last case no systemd daemon
 820           configuration is reloaded.</para>
 821         </listitem>
 822       </varlistentry>
 823
 824       <varlistentry>
 825         <term><command>disable <replaceable>NAME</replaceable>...</command></term>
 826
 827         <listitem>
 828           <para>Disables one or more units. This removes all symlinks
 829           to the specified unit files from the unit configuration
 830           directory, and hence undoes the changes made by
 831           <command>enable</command>. Note however that this removes
 832           all symlinks to the unit files (i.e. including manual
 833           additions), not just those actually created by
 834           <command>enable</command>. This call implicitly reloads the
 835           systemd daemon configuration after completing the disabling
 836           of the units. Note that this command does not implicitly
 837           stop the units that are being disabled. If this is desired
 838           an additional <command>stop</command> command should be
 839           executed afterwards.</para>
 840
 841           <para>This command will print the actions executed. This
 842           output may be suppressed by passing <option>--quiet</option>.
 843           </para>
 844
 845           <para>This command honors <option>--system</option>,
 846           <option>--user</option>, <option>--global</option> in a
 847           similar way as <command>enable</command>.</para>
 848         </listitem>
 849       </varlistentry>
 850
 851       <varlistentry>
 852         <term><command>is-enabled <replaceable>NAME</replaceable>...</command></term>
 853
 854         <listitem>
 855           <para>Checks whether any of the specified unit files are
 856           enabled (as with <command>enable</command>). Returns an exit
 857           code of 0 if at least one is enabled, non-zero
 858           otherwise. Prints the current enable status. To suppress
 859           this output use <option>--quiet</option>.</para>
 860         </listitem>
 861       </varlistentry>
 862
 863       <varlistentry>
 864         <term><command>reenable <replaceable>NAME</replaceable>...</command></term>
 865
 866         <listitem>
 867           <para>Reenable one or more unit files, as specified on the
 868           command line. This is a combination of
 869           <command>disable</command> and <command>enable</command> and
 870           is useful to reset the symlinks a unit is enabled with to
 871           the defaults configured in the <literal>[Install]</literal>
 872           section of the unit file.</para>
 873         </listitem>
 874       </varlistentry>
 875
 876       <varlistentry>
 877         <term><command>preset <replaceable>NAME</replaceable>...</command></term>
 878
 879         <listitem>
 880           <para>Reset one or more unit files, as specified on the
 881           command line, to the defaults configured in the preset
 882           policy files. This has the same effect as
 883           <command>disable</command> or <command>enable</command>,
 884           depending how the unit is listed in the preset files. For
 885           more information on preset policy format see
 886           <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 887           For more information on the concept of presets please
 888           consult the
 889           <ulink url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
 890           document.</para>
 891         </listitem>
 892       </varlistentry>
 893
 894       <varlistentry>
 895         <term><command>mask <replaceable>NAME</replaceable>...</command></term>
 896
 897         <listitem>
 898           <para>Mask one or more unit files, as specified on the
 899           command line. This will link these units to
 900           <filename>/dev/null</filename>, making it impossible to
 901           start them. This is a stronger version of
 902           <command>disable</command>, since it prohibits all kinds of
 903           activation of the unit, including manual activation. Use
 904           this option with care.</para>
 905         </listitem>
 906       </varlistentry>
 907
 908       <varlistentry>
 909         <term><command>unmask <replaceable>NAME</replaceable>...</command></term>
 910
 911         <listitem>
 912           <para>Unmask one or more unit files, as specified on the
 913           command line. This will undo the effect of
 914           <command>mask</command>.</para>
 915         </listitem>
 916       </varlistentry>
 917
 918       <varlistentry>
 919         <term><command>link <replaceable>FILENAME</replaceable>...</command></term>
 920
 921         <listitem>
 922           <para>Link a unit file that is not in the unit file search
 923           paths into the unit file search path. This requires an
 924           absolute path to a unit file. The effect of this can be
 925           undone with <command>disable</command>. The effect of this
 926           command is that a unit file is available for
 927           <command>start</command> and other commands although it
 928           isn't installed directly in the unit search path.</para>
 929         </listitem>
 930       </varlistentry>
 931
 932       <varlistentry>
 933         <term><command>load <replaceable>NAME</replaceable>...</command></term>
 934
 935         <listitem>
 936           <para>Load one or more units specified on the command
 937           line. This will simply load their configuration from disk,
 938           but not start them. To start them you need to use the
 939           <command>start</command> command which will implicitly load
 940           a unit that has not been loaded yet. Note that systemd
 941           garbage collects loaded units that are not active or
 942           referenced by an active unit. This means that units loaded
 943           this way will usually not stay loaded for long. Also note
 944           that this command cannot be used to reload unit
 945           configuration. Use the <command>daemon-reload</command>
 946           command for that. All in all, this command is of little use
 947           except for debugging.</para>
 948
 949           <para>This command should not be confused with the
 950           <command>daemon-reload</command> or
 951           <command>reload</command>.</para>
 952         </listitem>
 953       </varlistentry>
 954       <varlistentry>
 955         <term><command>list-jobs</command></term>
 956
 957         <listitem>
 958           <para>List jobs that are in progress.</para>
 959         </listitem>
 960       </varlistentry>
 961       <varlistentry>
 962         <term><command>cancel <replaceable>JOB</replaceable>...</command></term>
 963
 964         <listitem>
 965           <para>Cancel one or more jobs specified on the command line
 966           by their numeric job IDs. If no job id is specified, cancel
 967           all pending jobs.</para>
 968         </listitem>
 969       </varlistentry>
 970       <varlistentry>
 971         <term><command>dump</command></term>
 972
 973         <listitem>
 974           <para>Dump server status. This will output a (usually very
 975           long) human readable manager status dump. Its format is
 976           subject to change without notice and should not be parsed by
 977           applications.</para>
 978         </listitem>
 979       </varlistentry>
 980       <varlistentry>
 981         <term><command>list-dependencies <replaceable>NAME</replaceable></command></term>
 982
 983         <listitem>
 984           <para>Shows required and wanted units of the specified
 985           unit. If no unit is specified
 986           <filename>default.target</filename> is implied. Target units
 987           are recursively expanded.  When <option>--all</option> is
 988           passed all other units are recursively expanded as
 989           well.</para>
 990         </listitem>
 991       </varlistentry>
 992       <varlistentry>
 993         <term><command>snapshot [<replaceable>NAME</replaceable>]</command></term>
 994
 995         <listitem>
 996           <para>Create a snapshot. If a snapshot name is specified,
 997           the new snapshot will be named after it. If none is
 998           specified an automatic snapshot name is generated. In either
 999           case, the snapshot name used is printed to STDOUT, unless
1000           <option>--quiet</option> is specified.</para>
1001
1002           <para>A snapshot refers to a saved state of the systemd
1003           manager. It is implemented itself as a unit that is
1004           generated dynamically with this command and has dependencies
1005           on all units active at the time. At a later time the user
1006           may return to this state by using the
1007           <command>isolate</command> command on the snapshot unit.
1008           </para>
1009
1010           <para>Snapshots are only useful for saving and restoring
1011           which units are running or are stopped, they do not
1012           save/restore any other state. Snapshots are dynamic and lost
1013           on reboot.</para>
1014         </listitem>
1015       </varlistentry>
1016       <varlistentry>
1017         <term><command>delete <replaceable>NAME</replaceable>...</command></term>
1018
1019         <listitem>
1020           <para>Remove a snapshot previously created with
1021           <command>snapshot</command>.</para>
1022         </listitem>
1023       </varlistentry>
1024       <varlistentry>
1025         <term><command>daemon-reload</command></term>
1026
1027         <listitem>
1028           <para>Reload systemd manager configuration. This will reload
1029           all unit files and recreate the entire dependency
1030           tree. While the daemon is reloaded, all sockets systemd
1031           listens on on behalf of user configuration will stay
1032           accessible.</para> <para>This command should not be confused
1033           with the <command>load</command> or
1034           <command>reload</command> commands.</para>
1035         </listitem>
1036       </varlistentry>
1037       <varlistentry>
1038         <term><command>daemon-reexec</command></term>
1039
1040         <listitem>
1041           <para>Reexecute the systemd manager. This will serialize the
1042           manager state, reexecute the process and deserialize the
1043           state again. This command is of little use except for
1044           debugging and package upgrades. Sometimes it might be
1045           helpful as a heavy-weight <command>daemon-reload</command>.
1046           While the daemon is reexecuted all sockets systemd listens
1047           on on behalf of user configuration will stay accessible.
1048           </para>
1049         </listitem>
1050       </varlistentry>
1051       <varlistentry>
1052         <term><command>show-environment</command></term>
1053
1054         <listitem>
1055           <para>Dump the systemd manager environment block. The
1056           environment block will be dumped in straight-forward form
1057           suitable for sourcing into a shell script. This environment
1058           block will be passed to all processes the manager
1059           spawns.</para>
1060         </listitem>
1061       </varlistentry>
1062       <varlistentry>
1063         <term><command>set-environment <replaceable>VARIABLE=VALUE</replaceable>...</command></term>
1064
1065         <listitem>
1066           <para>Set one or more systemd manager environment variables,
1067           as specified on the command line.</para>
1068         </listitem>
1069       </varlistentry>
1070       <varlistentry>
1071         <term><command>unset-environment <replaceable>VARIABLE</replaceable>...</command></term>
1072
1073         <listitem>
1074           <para>Unset one or more systemd manager environment
1075           variables. If only a variable name is specified it will be
1076           removed regardless of its value. If a variable and a value
1077           are specified the variable is only removed if it has the
1078           specified value.</para>
1079         </listitem>
1080       </varlistentry>
1081       <varlistentry>
1082         <term><command>default</command></term>
1083
1084         <listitem>
1085           <para>Enter default mode. This is mostly equivalent to
1086           <command>isolate default.target</command>.</para>
1087         </listitem>
1088       </varlistentry>
1089       <varlistentry>
1090         <term><command>rescue</command></term>
1091
1092         <listitem>
1093           <para>Enter rescue mode. This is mostly equivalent to
1094           <command>isolate rescue.target</command> but also prints a
1095           wall message to all users.</para>
1096         </listitem>
1097       </varlistentry>
1098       <varlistentry>
1099         <term><command>emergency</command></term>
1100
1101         <listitem>
1102           <para>Enter emergency mode. This is mostly equivalent to
1103           <command>isolate emergency.target</command> but also prints
1104           a wall message to all users.</para>
1105         </listitem>
1106       </varlistentry>
1107       <varlistentry>
1108         <term><command>halt</command></term>
1109
1110         <listitem>
1111           <para>Shut down and halt the system. This is mostly equivalent to
1112           <command>start halt.target --irreversible</command> but also
1113           prints a wall message to all users.  If combined with
1114           <option>--force</option> shutdown of all running services is
1115           skipped, however all processes are killed and all file
1116           systems are unmounted or mounted read-only, immediately
1117           followed by the system halt.  If <option>--force</option> is
1118           specified twice the operation is immediately executed
1119           without terminating any processes or unmounting any file
1120           systems. This may result in data loss.</para>
1121         </listitem>
1122       </varlistentry>
1123       <varlistentry>
1124         <term><command>poweroff</command></term>
1125
1126         <listitem>
1127           <para>Shut down and power-off the system. This is mostly
1128           equivalent to <command>start poweroff.target --irreversible</command>
1129           but also prints a wall message to all users. If combined with
1130           <option>--force</option> shutdown of all running services is
1131           skipped, however all processes are killed and all file
1132           systems are unmounted or mounted read-only, immediately
1133           followed by the powering off. If <option>--force</option> is
1134           specified twice the operation is immediately executed
1135           without terminating any processes or unmounting any file
1136           systems. This may result in data loss.</para>
1137         </listitem>
1138       </varlistentry>
1139       <varlistentry>
1140         <term><command>reboot</command></term>
1141
1142         <listitem>
1143           <para>Shut down and reboot the system. This is mostly
1144           equivalent to <command>start reboot.target --irreversible</command>
1145           but also prints a wall message to all users. If combined with
1146           <option>--force</option> shutdown of all running services is
1147           skipped, however all processes are killed and all file
1148           systems are unmounted or mounted read-only, immediately
1149           followed by the reboot. If <option>--force</option> is
1150           specified twice the operation is immediately executed
1151           without terminating any processes or unmounting any file
1152           systems. This may result in data loss.</para>
1153         </listitem>
1154       </varlistentry>
1155       <varlistentry>
1156         <term><command>kexec</command></term>
1157
1158         <listitem>
1159           <para>Shut down and reboot the system via kexec. This is
1160           mostly equivalent to <command>start kexec.target --irreversible</command>
1161           but also prints a wall message to all users. If combined
1162           with <option>--force</option> shutdown of all running
1163           services is skipped, however all processes are killed and
1164           all file systems are unmounted or mounted read-only,
1165           immediately followed by the reboot.</para>
1166         </listitem>
1167       </varlistentry>
1168       <varlistentry>
1169         <term><command>exit</command></term>
1170
1171         <listitem>
1172           <para>Ask the systemd manager to quit. This is only
1173           supported for user service managers (i.e. in conjunction
1174           with the <option>--user</option> option) and will fail
1175           otherwise.</para>
1176         </listitem>
1177
1178       </varlistentry>
1179       <varlistentry>
1180         <term><command>suspend</command></term>
1181
1182         <listitem>
1183           <para>Suspend the system. This will trigger activation of
1184           the special <filename>suspend.target</filename> target.
1185           </para>
1186         </listitem>
1187       </varlistentry>
1188       <varlistentry>
1189         <term><command>hibernate</command></term>
1190
1191         <listitem>
1192           <para>Hibernate the system. This will trigger activation of
1193           the special <filename>hibernate.target</filename> target.
1194           </para>
1195         </listitem>
1196       </varlistentry>
1197       <varlistentry>
1198         <term><command>hybrid-sleep</command></term>
1199
1200         <listitem>
1201           <para>Hibernate and suspend the system. This will trigger
1202           activation of the special
1203           <filename>hybrid-sleep.target</filename> target.</para>
1204         </listitem>
1205       </varlistentry>
1206       <varlistentry>
1207         <term><command>switch-root <replaceable>ROOT</replaceable> [<replaceable>INIT</replaceable>]</command></term>
1208
1209         <listitem>
1210           <para>Switches to a different root directory and executes a
1211           new system manager process below it. This is intended for
1212           usage in initial RAM disks ("initrd"), and will transition
1213           from the initrd's system manager process (a.k.a "init"
1214           process) to the main system manager process. Takes two
1215           arguments: the directory to make the new root directory, and
1216           the path to the new system manager binary below it to
1217           execute as PID 1. If the latter is omitted or the empty
1218           string, a systemd binary will automatically be searched for
1219           and used as init. If the system manager path is omitted or
1220           equal to the empty string the state of the initrd's system
1221           manager process is passed to the main system manager, which
1222           allows later introspection of the state of the services
1223           involved in the initrd boot.</para>
1224         </listitem>
1225       </varlistentry>
1226     </variablelist>
1227
1228   </refsect1>
1229
1230   <refsect1>
1231     <title>Exit status</title>
1232
1233     <para>On success 0 is returned, a non-zero failure
1234     code otherwise.</para>
1235   </refsect1>
1236
1237   <refsect1>
1238     <title>Environment</title>
1239
1240     <variablelist class='environment-variables'>
1241       <varlistentry>
1242         <term><varname>$SYSTEMD_PAGER</varname></term>
1243
1244         <listitem>
1245           <para>Pager to use when <option>--no-pager</option> is not
1246           given; overrides <varname>$PAGER</varname>.  Setting this to
1247           an empty string or the value <literal>cat</literal> is
1248           equivalent to passing
1249           <option>--no-pager</option>.</para>
1250         </listitem>
1251       </varlistentry>
1252     </variablelist>
1253   </refsect1>
1254
1255   <refsect1>
1256     <title>See Also</title>
1257     <para>
1258       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1259       <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1260       <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1261       <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1262       <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1263       <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1264       <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1265       <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1266     </para>
1267   </refsect1>
1268
1269 </refentry>