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