man/systemctl.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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   6   This file is part of systemd.
   7
   8   Copyright 2010 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU General Public License as published by
  12   the Free Software Foundation; either version 2 of the License, or
  13   (at your option) any later version.
  14
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  16   WITHOUT ANY WARRANTY; without even the implied warranty of
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  18   General Public License for more details.
  19
  20   You should have received a copy of the GNU General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
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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 session manager</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <cmdsynopsis>
  52                         <command>systemctl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg> <arg choice="opt" rep="repeat">NAME</arg></command>
  53                 </cmdsynopsis>
  54         </refsynopsisdiv>
  55
  56         <refsect1>
  57                 <title>Description</title>
  58
  59                 <para><command>systemctl</command> may be used to
  60                 introspect and control the state of the
  61                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  62                 system and session manager.</para>
  63         </refsect1>
  64
  65         <refsect1>
  66                 <title>Options</title>
  67
  68                 <para>The following options are understood:</para>
  69
  70                 <variablelist>
  71                         <varlistentry>
  72                                 <term><option>--help</option></term>
  73                                 <term><option>-h</option></term>
  74
  75                                 <listitem><para>Prints a short help
  76                                 text and exits.</para></listitem>
  77                         </varlistentry>
  78
  79                         <varlistentry>
  80                                 <term><option>--version</option></term>
  81
  82                                 <listitem><para>Prints a short version
  83                                 string and exits.</para></listitem>
  84                         </varlistentry>
  85
  86                         <varlistentry>
  87                                 <term><option>--type=</option></term>
  88                                 <term><option>-t</option></term>
  89
  90                                 <listitem><para>When listing units,
  91                                 limit display to certain unit
  92                                 types. If not specified units of all
  93                                 types will be shown. The argument
  94                                 should be a unit type name such as
  95                                 <option>service</option>,
  96                                 <option>socket</option> and
  97                                 similar.</para></listitem>
  98                         </varlistentry>
  99
 100                         <varlistentry>
 101                                 <term><option>--property=</option></term>
 102                                 <term><option>-p</option></term>
 103
 104                                 <listitem><para>When showing
 105                                 unit/job/manager information, limit
 106                                 display to certain properties as
 107                                 specified as argument. If not
 108                                 specified all set properties are
 109                                 shown. The argument should be a
 110                                 property name, such as
 111                                 <literal>MainPID</literal>. If
 112                                 specified more than once all
 113                                 properties with the specified names
 114                                 are shown.</para></listitem>
 115                         </varlistentry>
 116
 117                         <varlistentry>
 118                                 <term><option>--all</option></term>
 119                                 <term><option>-a</option></term>
 120
 121                                 <listitem><para>When listing units,
 122                                 show all units, regardless of their
 123                                 state, including inactive units. When
 124                                 showing unit/job/manager information,
 125                                 show all properties regardless whether
 126                                 they are set or not.</para></listitem>
 127                         </varlistentry>
 128
 129                         <varlistentry>
 130                                 <term><option>--full</option></term>
 131
 132                                 <listitem><para>Do not ellipsize unit
 133                                 names and truncate unit descriptions
 134                                 in the output of
 135                                 <command>list-units</command> and
 136                                 <command>list-jobs</command>.</para></listitem>
 137                         </varlistentry>
 138
 139                         <varlistentry>
 140                                 <term><option>--fail</option></term>
 141
 142                                 <listitem><para>If the requested
 143                                 operation conflicts with a pending
 144                                 unfinished job, fail the command. If
 145                                 this is not specified the requested
 146                                 operation will replace the pending job,
 147                                 if necessary.</para></listitem>
 148                         </varlistentry>
 149
 150                         <varlistentry>
 151                                 <term><option>--quiet</option></term>
 152                                 <term><option>-q</option></term>
 153
 154                                 <listitem><para>Suppress output to
 155                                 STDOUT in
 156                                 <command>snapshot</command>,
 157                                 <command>check</command>,
 158                                 <command>enable</command> and
 159                                 <command>disable</command>.</para></listitem>
 160                         </varlistentry>
 161
 162                         <varlistentry>
 163                                 <term><option>--no-block</option></term>
 164
 165                                 <listitem><para>Do not synchronously wait for
 166                                 the requested operation to finish. If this is
 167                                 not specified the job will be verified,
 168                                 enqueued and <command>systemctl</command> will
 169                                 wait until it is completed. By passing this
 170                                 argument it is only verified and
 171                                 enqueued.</para></listitem> </varlistentry>
 172
 173                         <varlistentry>
 174                                 <term><option>--system</option></term>
 175
 176                                 <listitem><para>Talk to the systemd
 177                                 system manager. (Default)</para></listitem>
 178                         </varlistentry>
 179
 180                         <varlistentry>
 181                                 <term><option>--session</option></term>
 182
 183                                 <listitem><para>Talk to the systemd
 184                                 session manager of the calling user.</para></listitem>
 185                         </varlistentry>
 186
 187                         <varlistentry>
 188                                 <term><option>--order</option></term>
 189                                 <term><option>--require</option></term>
 190
 191                                 <listitem><para>When used in
 192                                 conjunction with the
 193                                 <command>dot</command> command (see
 194                                 below), selects which dependencies are
 195                                 shown in the dependency graph. If
 196                                 <option>--order</option> is passed
 197                                 only dependencies of type
 198                                 <varname>After=</varname> or
 199                                 <varname>Before=</varname> are
 200                                 shown. If <option>--require</option>
 201                                 is passed only dependencies of type
 202                                 <varname>Requires=</varname>,
 203                                 <varname>RequiresOverridable=</varname>,
 204                                 <varname>Requisite=</varname>,
 205                                 <varname>RequisiteOverridable=</varname>,
 206                                 <varname>Wants=</varname> and
 207                                 <varname>Conflicts=</varname> are
 208                                 shown. If neither is passed, shows
 209                                 dependencies of all these
 210                                 types.</para></listitem>
 211                         </varlistentry>
 212
 213                         <varlistentry>
 214                                 <term><option>--no-wall</option></term>
 215
 216                                 <listitem><para>Don't send wall
 217                                 message before
 218                                 halt, power-off, reboot.</para></listitem>
 219                         </varlistentry>
 220
 221                         <varlistentry>
 222                                 <term><option>--global</option></term>
 223
 224                                 <listitem><para>When used with
 225                                 <command>enable</command> and
 226                                 <command>disable</command>, operate on the
 227                                 global session configuŕation
 228                                 directory, thus enabling or disabling
 229                                 a unit file globally for all future
 230                                 sessions of all users.</para></listitem>
 231                         </varlistentry>
 232
 233                         <varlistentry>
 234                                 <term><option>--no-reload</option></term>
 235
 236                                 <listitem><para>When used with
 237                                 <command>enable</command> and
 238                                 <command>disable</command>, do not
 239                                 implicitly reload daemon configuration
 240                                 after executing the
 241                                 changes.</para></listitem>
 242                         </varlistentry>
 243
 244                         <varlistentry>
 245                                 <term><option>--no-ask-password</option></term>
 246
 247                                 <listitem><para>When used with
 248                                 <command>start</command> and related
 249                                 commands, disables asking for
 250                                 passwords. Background services may
 251                                 require input of a password or
 252                                 passphrase string, for example to
 253                                 unlock system hard disks or
 254                                 cryptographic certificates. Unless
 255                                 this option is specified and the
 256                                 command is invoked from a terminal
 257                                 <command>systemctl</command> will
 258                                 query the user on the terminal for the
 259                                 necessary secrets. Use this option to
 260                                 switch this behaviour off. In this
 261                                 case the password must be supplied by
 262                                 some other means (for example
 263                                 graphical password agents) or the
 264                                 service might fail.</para></listitem>
 265                         </varlistentry>
 266
 267                         <varlistentry>
 268                                 <term><option>--kill-mode=</option></term>
 269
 270                                 <listitem><para>When used with
 271                                 <command>kill</command>, choose the
 272                                 mode how to kill the selected
 273                                 processes. Must be one of
 274                                 <option>control-group</option>,
 275                                 <option>process-group</option> or
 276                                 <option>process</option> to select
 277                                 whether to kill the entire control
 278                                 group, the process group or only the
 279                                 selected process itself. If ommitted
 280                                 defaults to
 281                                 <option>control-group</option> if
 282                                 <option>--kill-who=all</option> is
 283                                 set, or <option>process</option>
 284                                 otherwise. You probably never need to
 285                                 use this switch.</para></listitem>
 286                         </varlistentry>
 287
 288                         <varlistentry>
 289                                 <term><option>--kill-who=</option></term>
 290
 291                                 <listitem><para>When used with
 292                                 <command>kill</command>, choose which
 293                                 processes to kill. Must be one of
 294                                 <option>main</option>,
 295                                 <option>control</option> or
 296                                 <option>all</option> to select whether
 297                                 to kill only the main process of the
 298                                 unit, the control process or all
 299                                 processes of the unit. If ommitted
 300                                 defaults to
 301                                 <option>all</option>.</para></listitem>
 302                         </varlistentry>
 303
 304                         <varlistentry>
 305                                 <term><option>---signal=</option></term>
 306                                 <term><option>-s</option></term>
 307
 308                                 <listitem><para>When used with
 309                                 <command>kill</command>, choose which
 310                                 signal to send to selected
 311                                 processes. Must be one of the well
 312                                 know signal specifiers such as
 313                                 SIGTERM, SIGINT or SIGSTOP. If
 314                                 ommitted defaults to
 315                                 <option>SIGTERM</option>.</para></listitem>
 316                         </varlistentry>
 317
 318                         <varlistentry>
 319                                 <term><option>--force</option></term>
 320                                 <term><option>-f</option></term>
 321
 322                                 <listitem><para>When used with
 323                                 <command>enable</command>, override any
 324                                 existing conflicting
 325                                 symlinks.</para></listitem>
 326
 327                                 <listitem><para>When used with
 328                                 <command>halt</command>,
 329                                 <command>poweroff</command>,
 330                                 <command>reboot</command> or
 331                                 <command>kexec</command> execute
 332                                 selected operation without shutting
 333                                 down all units. However, all processes
 334                                 will be killed forcibly and all file
 335                                 systems are unmounted or remounted
 336                                 read-only. This is hence a drastic but
 337                                 relatively safe option to request an
 338                                 immediate reboot.</para></listitem>
 339                         </varlistentry>
 340
 341                         <varlistentry>
 342                                 <term><option>--defaults</option></term>
 343
 344                                 <listitem><para>When used with
 345                                 <command>disable</command>, ensures
 346                                 that only the symlinks created by
 347                                 <command>enable</command> are removed,
 348                                 not all symlinks pointing to the unit
 349                                 file that shall be
 350                                 disabled.</para></listitem>
 351                         </varlistentry>
 352                 </variablelist>
 353
 354                 <para>The following commands are understood:</para>
 355
 356                 <variablelist>
 357                         <varlistentry>
 358                                 <term><command>list-units</command></term>
 359
 360                                 <listitem><para>List known units.</para></listitem>
 361                         </varlistentry>
 362                         <varlistentry>
 363                                 <term><command>start [NAME...]</command></term>
 364
 365                                 <listitem><para>Start (activate) one
 366                                 or more units specified on the command
 367                                 line.</para></listitem>
 368                         </varlistentry>
 369                         <varlistentry>
 370                                 <term><command>stop [NAME...]</command></term>
 371
 372                                 <listitem><para>Stop (deactivate) one
 373                                 or more units specified on the command
 374                                 line.</para></listitem>
 375                         </varlistentry>
 376                         <varlistentry>
 377                                 <term><command>reload [NAME...]</command></term>
 378
 379                                 <listitem><para>Asks all units listed
 380                                 on the command line to reload their
 381                                 configuration. Note that this will
 382                                 reload the service-specific
 383                                 configuration, not the unit
 384                                 configuration file of systemd. If you
 385                                 want systemd to reload the
 386                                 configuration file of a unit use the
 387                                 <command>daemon-reload</command>
 388                                 command. In other words: for the
 389                                 example case of Apache, this will
 390                                 reload Apache's
 391                                 <filename>httpd.conf</filename> in the
 392                                 web server, not the
 393                                 <filename>apache.service</filename>
 394                                 systemd unit file. </para>
 395
 396                                 <para>This command should not be
 397                                 confused with the
 398                                 <command>daemon-reload</command> or
 399                                 <command>load</command>
 400                                 commands.</para></listitem>
 401
 402                         </varlistentry>
 403                         <varlistentry>
 404                                 <term><command>restart [NAME...]</command></term>
 405
 406                                 <listitem><para>Restart one or more
 407                                 units specified on the command
 408                                 line. If the units are not running yet
 409                                 they will be
 410                                 started.</para></listitem>
 411                         </varlistentry>
 412                         <varlistentry>
 413                                 <term><command>try-restart [NAME...]</command></term>
 414
 415                                 <listitem><para>Restart one or more
 416                                 units specified on the command
 417                                 line. If the units are not running yet
 418                                 the operation will
 419                                 fail.</para></listitem>
 420                         </varlistentry>
 421                         <varlistentry>
 422                                 <term><command>reload-or-restart [NAME...]</command></term>
 423                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 424
 425                                 <listitem><para>Reload one or more
 426                                 units if they support it. If not,
 427                                 restart them instead. Note that for
 428                                 compatibility with SysV and Red Hat
 429                                 init scripts
 430                                 <command>force-reload</command> and
 431                                 <command>condrestart</command> may be
 432                                 used as equivalent commands to
 433                                 <command>reload-or-try-restart</command>.</para></listitem>
 434                         </varlistentry>
 435                         <varlistentry>
 436                                 <term><command>isolate [NAME]</command></term>
 437
 438                                 <listitem><para>Start the unit
 439                                 specified on the command line and its
 440                                 dependencies and stop all others.</para>
 441
 442                                 <para>This is similar to changing the
 443                                 runlevel in a traditional init system. The
 444                                 <command>isolate</command> command will
 445                                 immediately stop processes that are not
 446                                 enabled in the new unit, possibly including
 447                                 the graphical environment or terminal you
 448                                 are currently using.</para>
 449
 450                                 <para>Note that this works only on units
 451                                 where <option>AllowIsolate=</option> is
 452                                 enabled. See
 453                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 454                                 for details.</para></listitem>
 455                         </varlistentry>
 456                         <varlistentry>
 457                                 <term><command>kill [NAME...]</command></term>
 458
 459                                 <listitem><para>Send a signal to one
 460                                 or more processes of the unit. Use
 461                                 <option>--kill-who=</option> to select
 462                                 which process to kill. Use
 463                                 <option>--kill-mode=</option> to
 464                                 select the kill mode and
 465                                 <option>--signal=</option> to select
 466                                 the signal to send.</para></listitem>
 467                         </varlistentry>
 468                         <varlistentry>
 469                                 <term><command>is-active [NAME...]</command></term>
 470
 471                                 <listitem><para>Check whether any of
 472                                 the specified units is active
 473                                 (i.e. running). Returns an exit code
 474                                 0 if at least one is active, non-zero
 475                                 otherwise. Unless
 476                                 <option>--quiet</option> is specified
 477                                 this will also print the current unit
 478                                 state to STDOUT.</para></listitem>
 479                         </varlistentry>
 480                         <varlistentry>
 481                                 <term><command>status [NAME...|PID...]</command></term>
 482
 483                                 <listitem><para>Show terse runtime
 484                                 status information about one or more
 485                                 units. This function is intended to
 486                                 generate human-readable output. If you
 487                                 are looking for computer-parsable
 488                                 output, use <command>show</command>
 489                                 instead. If a PID is passed
 490                                 information about the unit the process
 491                                 of the PID belongs to is
 492                                 shown.</para></listitem>
 493                         </varlistentry>
 494                         <varlistentry>
 495                                 <term><command>show [NAME...|JOB...]</command></term>
 496
 497                                 <listitem><para>Show properties of one
 498                                 or more units, jobs or the manager
 499                                 itself. If no argument is specified
 500                                 properties of the manager will be
 501                                 shown. If a unit name is specified
 502                                 properties of the unit is shown, and
 503                                 if a job id is specified properties of
 504                                 the job is shown. By default, empty
 505                                 properties are suppressed. Use
 506                                 <option>--all</option> to show those
 507                                 too. To select specific properties to
 508                                 show use
 509                                 <option>--property=</option>. This
 510                                 command is intended to be used
 511                                 whenever computer-parsable output is
 512                                 required. Use
 513                                 <command>status</command> if you are
 514                                 looking for formatted human-readable
 515                                 output.</para></listitem>
 516                         </varlistentry>
 517
 518                         <varlistentry>
 519                                 <term><command>reset-failed [NAME...]</command></term>
 520
 521                                 <listitem><para>Reset the
 522                                 '<literal>failed</literal>' state of the
 523                                 specified units, or if no unit name is
 524                                 passed of all units. When a unit fails
 525                                 in some way (i.e. process exiting with
 526                                 non-zero error code, terminating
 527                                 abnormally or timing out) it will
 528                                 automatically enter the
 529                                 '<literal>failed</literal>' state and
 530                                 its exit code and status is recorded
 531                                 for introspection by the administrator
 532                                 until the service is restarted or
 533                                 reset with this
 534                                 command.</para></listitem>
 535                         </varlistentry>
 536
 537                         <varlistentry>
 538                                 <term><command>enable [NAME...]</command></term>
 539
 540                                 <listitem><para>Enable one or more
 541                                 unit files, as specified on the
 542                                 command line. This will create a
 543                                 number of symlinks as encoded in the
 544                                 <literal>[Install]</literal> sections
 545                                 of the unit files. After the symlinks
 546                                 have been created the systemd
 547                                 configuration is reloaded (in a way
 548                                 that is equivalent to
 549                                 <command>daemon-reload</command>) to
 550                                 ensure the changes are taken into
 551                                 account immediately. Note that this
 552                                 does not have the effect that any of
 553                                 the units enabled are also started at
 554                                 the same time. If this is desired a
 555                                 separate <command>start</command>
 556                                 command must be invoked for the
 557                                 unit.</para>
 558
 559                                 <para>This command will
 560                                 print the actions executed. This
 561                                 output may be suppressed by passing
 562                                 <option>--quiet</option>.</para>
 563
 564                                 <para>Note that this operation creates
 565                                 only the suggested symlinks for the
 566                                 units. While this command is the
 567                                 recommended way to manipulate the unit
 568                                 configuration directory, the
 569                                 administrator is free to make
 570                                 additional changes manually, by
 571                                 placing or removing symlinks in the
 572                                 directory. This is particular useful
 573                                 to create configurations that deviate
 574                                 from the suggested default
 575                                 installation. In this case the
 576                                 administrator must make sure to invoke
 577                                 <command>daemon-reload</command>
 578                                 manually as necessary, to ensure his
 579                                 changes are taken into account.</para>
 580
 581                                 <para>Enabling units should not be
 582                                 confused with starting (activating)
 583                                 units, as done by the
 584                                 <command>start</command>
 585                                 command. Enabling and starting units
 586                                 is orthogonal: units may be enabled
 587                                 without being started and started
 588                                 without being enabled. Enabling simply
 589                                 hooks the unit into various suggested
 590                                 places (for example, so that the unit
 591                                 is automatically started on boot or
 592                                 when a particular kind of hardware is
 593                                 plugged in). Starting actually spawns
 594                                 the daemon process (in case of service
 595                                 units), or binds the socket (in case
 596                                 of socket units), and so
 597                                 on.</para>
 598
 599                                 <para>Depending on whether
 600                                 <option>--system</option>,
 601                                 <option>--session</option> or
 602                                 <option>--global</option> is specified
 603                                 this enables the unit for the system,
 604                                 for sessions of the calling user only
 605                                 or for all future session of all
 606                                 users. Note that in the latter case no
 607                                 systemd daemon configuration is
 608                                 reloaded.</para>
 609                                 </listitem>
 610                         </varlistentry>
 611
 612                         <varlistentry>
 613                                 <term><command>disable [NAME...]</command></term>
 614
 615                                 <listitem><para>Disables one or more
 616                                 units. This removes all symlinks to
 617                                 the specified unit files from the unit
 618                                 configuration directory, and hence
 619                                 undoes the changes made by
 620                                 <command>enable</command>. Note
 621                                 however that this by default removes
 622                                 all symlinks to the unit files
 623                                 (i.e. including manual additions), not
 624                                 just those actually created by
 625                                 <command>enable</command>. If only the
 626                                 symlinks that are suggested by default
 627                                 shall be removed, pass
 628                                 <option>--defaults</option>. This
 629                                 implicitly reloads the systemd daemon
 630                                 configuration after completing the
 631                                 disabling of the units. Note that this
 632                                 command does not implicitly stop the
 633                                 units that is being disabled. If this
 634                                 is desired an additional
 635                                 <command>stop</command>command should
 636                                 be executed afterwards.</para>
 637
 638                                 <para>This command will print the
 639                                 actions executed. This output may be
 640                                 suppressed by passing
 641                                 <option>--quiet</option>.</para>
 642                                 </listitem>
 643
 644                                 <para>This command honours
 645                                 <option>--system</option>,
 646                                 <option>--session</option>,
 647                                 <option>--global</option> in a similar
 648                                 way as
 649                                 <command>enable</command>.</para>
 650                         </varlistentry>
 651
 652                         <varlistentry>
 653                                 <term><command>is-enabled [NAME...]</command></term>
 654
 655                                 <listitem><para>Checks whether any of
 656                                 the specified unit files is enabled
 657                                 (as with
 658                                 <command>enable</command>). Returns an
 659                                 exit code of 0 if at least one is
 660                                 enabled, non-zero
 661                                 otherwise.</para></listitem>
 662                         </varlistentry>
 663
 664                         <varlistentry>
 665                                 <term><command>load [NAME...]</command></term>
 666
 667                                 <listitem><para>Load one or more units
 668                                 specified on the command line. This
 669                                 will simply load their configuration
 670                                 from disk, but not start them. To
 671                                 start them you need to use the
 672                                 <command>start</command> command which
 673                                 will implicitly load a unit that has
 674                                 not been loaded yet. Note that systemd
 675                                 garbage collects loaded units that are
 676                                 not active or referenced by an active
 677                                 unit. This means that units loaded
 678                                 this way will usually not stay loaded
 679                                 for long. Also note that this command
 680                                 cannot be used to reload unit
 681                                 configuration. Use the
 682                                 <command>daemon-reload</command>
 683                                 command for that. All in all, this
 684                                 command is of little use except for
 685                                 debugging.</para>
 686                                 <para>This command should not be
 687                                 confused with the
 688                                 <command>daemon-reload</command> or
 689                                 <command>reload</command>
 690                                 commands.</para></listitem>
 691                         </varlistentry>
 692                         <varlistentry>
 693                                 <term><command>list-jobs</command></term>
 694
 695                                 <listitem><para>List jobs that are in progress.</para></listitem>
 696                         </varlistentry>
 697                         <varlistentry>
 698                                 <term><command>cancel [JOB...]</command></term>
 699
 700                                 <listitem><para>Cancel one or more
 701                                 jobs specified on the command line by
 702                                 their numeric job
 703                                 IDs. If not job id is specified cancels all jobs that are pending.</para></listitem>
 704                         </varlistentry>
 705                         <varlistentry>
 706                                 <term><command>monitor</command></term>
 707
 708                                 <listitem><para>Monitor unit/job
 709                                 changes. This is mostly useful for
 710                                 debugging purposes and prints a line
 711                                 each time systemd loads or unloads a
 712                                 unit configuration file, or a unit
 713                                 property changes.</para></listitem>
 714                         </varlistentry>
 715                         <varlistentry>
 716                                 <term><command>dump</command></term>
 717
 718                                 <listitem><para>Dump server
 719                                 status. This will output a (usually
 720                                 very long) human readable manager
 721                                 status dump. Its format is subject to
 722                                 change without notice and should not
 723                                 be parsed by
 724                                 applications.</para></listitem>
 725                         </varlistentry>
 726                         <varlistentry>
 727                                 <term><command>dot</command></term>
 728
 729                                 <listitem><para>Generate textual
 730                                 dependency graph description in dot
 731                                 format for further processing with the
 732                                 GraphViz
 733                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 734                                 tool. Use a command line like
 735                                 <command>systemctl dot | dot -Tsvg >
 736                                 systemd.svg</command> to generate a
 737                                 graphical dependency tree. Unless
 738                                 <option>--order</option> or
 739                                 <option>--require</option> is passed
 740                                 the generated graph will show both
 741                                 ordering and requirement
 742                                 dependencies.</para></listitem>
 743                         </varlistentry>
 744                         <varlistentry>
 745                                 <term><command>snapshot [NAME]</command></term>
 746
 747                                 <listitem><para>Create a snapshot. If
 748                                 a snapshot name is specified, the new
 749                                 snapshot will be named after it. If
 750                                 none is specified an automatic
 751                                 snapshot name is generated. In either
 752                                 case, the snapshot name used is
 753                                 printed to STDOUT, unless
 754                                 <option>--quiet</option> is
 755                                 specified.</para>
 756
 757                                 <para>A snapshot refers to a saved
 758                                 state of the systemd manager. It is
 759                                 implemented itself as unit that is
 760                                 generated dynamically with this
 761                                 command and has dependencies on all
 762                                 units active at the time. At a later
 763                                 time the user may return to this state
 764                                 by using the
 765                                 <command>isolate</command> command on
 766                                 the snapshot unit.</para></listitem>
 767
 768                                 <para>Snapshots are only useful for
 769                                 saving and restoring which units are
 770                                 running or are stopped, they do not
 771                                 save/restore any other
 772                                 state. Snapshots are dynamic and lost
 773                                 on reboot.</para>
 774                         </varlistentry>
 775                         <varlistentry>
 776                                 <term><command>delete [NAME...]</command></term>
 777
 778                                 <listitem><para>Remove a snapshot
 779                                 previously created with
 780                                 <command>snapshot</command>.</para></listitem>
 781                         </varlistentry>
 782                         <varlistentry>
 783                                 <term><command>daemon-reload</command></term>
 784
 785                                 <listitem><para>Reload systemd manager
 786                                 configuration. This will reload all
 787                                 unit files and recreate the entire
 788                                 dependency tree. While the daemon is
 789                                 reloaded, all sockets systemd listens
 790                                 on on behalf of user configuration will
 791                                 stay accessible.</para> <para>This
 792                                 command should not be confused with
 793                                 the <command>load</command> or
 794                                 <command>reload</command>
 795                                 commands.</para></listitem>
 796                         </varlistentry>
 797                         <varlistentry>
 798                                 <term><command>daemon-reexec</command></term>
 799
 800                                 <listitem><para>Reexecute the systemd
 801                                 manager. This will serialize the
 802                                 manager state, reexecute the process
 803                                 and deserialize the state again. This
 804                                 command is of little use except for
 805                                 debugging and package
 806                                 upgrades. Sometimes it might be
 807                                 helpful as a heavy-weight
 808                                 <command>daemon-reload</command>. While
 809                                 the daemon is reexecuted all sockets
 810                                 systemd listens on on behalf of user
 811                                 configuration will stay
 812                                 accessible.</para></listitem>
 813                         </varlistentry>
 814                         <varlistentry>
 815                                 <term><command>show-environment</command></term>
 816
 817                                 <listitem><para>Dump the systemd
 818                                 manager environment block. The
 819                                 environment block will be dumped in
 820                                 straight-forward form suitable for
 821                                 sourcing into a shell script. This
 822                                 environment block will be passed to
 823                                 all processes the manager
 824                                 spawns.</para></listitem>
 825                         </varlistentry>
 826                         <varlistentry>
 827                                 <term><command>set-environment [NAME=VALUE...]</command></term>
 828
 829                                 <listitem><para>Set one or more
 830                                 systemd manager environment variables,
 831                                 as specified on the command
 832                                 line.</para></listitem>
 833                         </varlistentry>
 834                         <varlistentry>
 835                                 <term><command>unset-environment [NAME...]</command></term>
 836
 837                                 <listitem><para>Unset one or more
 838                                 systemd manager environment
 839                                 variables. If only a variable name is
 840                                 specified it will be removed
 841                                 regardless of its value. If a variable
 842                                 and a value are specified the variable
 843                                 is only removed if it has the
 844                                 specified value.</para></listitem>
 845                         </varlistentry>
 846                         <varlistentry>
 847                                 <term><command>default</command></term>
 848
 849                                 <listitem><para>Enter default
 850                                 mode. This is mostly equivalent to
 851                                 <command>start
 852                                 default.target</command>.</para></listitem>
 853                         </varlistentry>
 854                         <varlistentry>
 855                                 <term><command>rescue</command></term>
 856
 857                                 <listitem><para>Enter rescue
 858                                 mode. This is mostly equivalent to
 859                                 <command>isolate
 860                                 rescue.target</command> but also
 861                                 prints a wall message to all
 862                                 users.</para></listitem>
 863                         </varlistentry>
 864                         <varlistentry>
 865                                 <term><command>emergency</command></term>
 866
 867                                 <listitem><para>Enter emergency
 868                                 mode. This is mostly equivalent to
 869                                 <command>isolate
 870                                 emergency.target</command> but also
 871                                 prints a wall message to all
 872                                 users.</para></listitem>
 873                         </varlistentry>
 874                         <varlistentry>
 875                                 <term><command>halt</command></term>
 876
 877                                 <listitem><para>Shut down and halt the
 878                                 system. This is mostly equivalent to
 879                                 <command>start halt.target</command>
 880                                 but also prints a wall message to all
 881                                 users.  If
 882                                 combined with <option>--force</option>
 883                                 shutdown of all running services is
 884                                 skipped, however all processes killed
 885                                 and all file systems unmounted or
 886                                 mounted read-only, immediately
 887                                 followed by the
 888                                 system halt.</para></listitem>
 889                         </varlistentry>
 890                         <varlistentry>
 891                                 <term><command>poweroff</command></term>
 892
 893                                 <listitem><para>Shut down and
 894                                 power-off the system. This is mostly
 895                                 equivalent to <command>start
 896                                 poweroff.target</command> but also
 897                                 prints a wall message to all
 898                                 users. If
 899                                 combined with <option>--force</option>
 900                                 shutdown of all running services is
 901                                 skipped, however all processes killed
 902                                 and all file systems unmounted or
 903                                 mounted read-only, immediately
 904                                 followed by the
 905                                 powering off.</para></listitem>
 906                         </varlistentry>
 907                         <varlistentry>
 908                                 <term><command>reboot</command></term>
 909
 910                                 <listitem><para>Shut down and
 911                                 reboot the system. This is mostly
 912                                 equivalent to <command>start
 913                                 reboot.target</command> but also
 914                                 prints a wall message to all
 915                                 users. If
 916                                 combined with <option>--force</option>
 917                                 shutdown of all running services is
 918                                 skipped, however all processes killed
 919                                 and all file systems unmounted or
 920                                 mounted read-only, immediately
 921                                 followed by the
 922                                 reboot.</para></listitem>
 923                         </varlistentry>
 924                         <varlistentry>
 925                                 <term><command>kexec</command></term>
 926
 927                                 <listitem><para>Shut down and reboot
 928                                 the system via kexec. This is mostly
 929                                 equivalent to <command>start
 930                                 kexec.target</command> but also prints
 931                                 a wall message to all users. If
 932                                 combined with <option>--force</option>
 933                                 shutdown of all running services is
 934                                 skipped, however all processes killed
 935                                 and all file systems unmounted or
 936                                 mounted read-only, immediately
 937                                 followed by the
 938                                 reboot.</para></listitem>
 939                         </varlistentry>
 940                         <varlistentry>
 941                                 <term><command>exit</command></term>
 942
 943                                 <listitem><para>Ask the systemd
 944                                 manager to quit. This is only
 945                                 supported for session managers
 946                                 (i.e. in conjunction with the
 947                                 <option>--session</option> option) and
 948                                 will fail otherwise.</para></listitem>
 949                         </varlistentry>
 950                 </variablelist>
 951
 952         </refsect1>
 953
 954         <refsect1>
 955                 <title>Exit status</title>
 956
 957                 <para>On success 0 is returned, a non-zero failure
 958                 code otherwise.</para>
 959         </refsect1>
 960
 961         <refsect1>
 962                 <title>See Also</title>
 963                 <para>
 964                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 965                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 966                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 967                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 968                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 969                 </para>
 970         </refsect1>
 971
 972 </refentry>