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