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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  18   General Public License for more details.
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  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 service 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 service 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>--failed</option></term>
 131
 132                                 <listitem><para>When listing units,
 133                                 show only failed units. Do not confuse
 134                                 with
 135                                 <option>--fail</option>.</para></listitem>
 136                         </varlistentry>
 137
 138                         <varlistentry>
 139                                 <term><option>--full</option></term>
 140
 141                                 <listitem><para>Do not ellipsize unit
 142                                 names and truncate unit descriptions
 143                                 in the output of
 144                                 <command>list-units</command> and
 145                                 <command>list-jobs</command>.</para></listitem>
 146                         </varlistentry>
 147
 148                         <varlistentry>
 149                                 <term><option>--fail</option></term>
 150
 151                                 <listitem><para>If the requested
 152                                 operation conflicts with a pending
 153                                 unfinished job, fail the command. If
 154                                 this is not specified the requested
 155                                 operation will replace the pending job,
 156                                 if necessary. Do not confuse
 157                                 with
 158                                 <option>--failed</option>.</para></listitem>
 159                         </varlistentry>
 160
 161                         <varlistentry>
 162                                 <term><option>--ignore-dependencies</option></term>
 163
 164                                 <listitem><para>When enqueuing a new
 165                                 job ignore all its dependencies and
 166                                 execute it immediately. If passed no
 167                                 required units of the unit passed will
 168                                 be pulled in, and no ordering
 169                                 dependencies will be honoured. This is
 170                                 mostly a debugging and rescue tool for
 171                                 the administrator and should not be
 172                                 used by
 173                                 applications.</para></listitem>
 174                         </varlistentry>
 175
 176                         <varlistentry>
 177                                 <term><option>--quiet</option></term>
 178                                 <term><option>-q</option></term>
 179
 180                                 <listitem><para>Suppress output to
 181                                 STDOUT in
 182                                 <command>snapshot</command>,
 183                                 <command>is-active</command>,
 184                                 <command>enable</command> and
 185                                 <command>disable</command>.</para></listitem>
 186                         </varlistentry>
 187
 188                         <varlistentry>
 189                                 <term><option>--no-block</option></term>
 190
 191                                 <listitem><para>Do not synchronously wait for
 192                                 the requested operation to finish. If this is
 193                                 not specified the job will be verified,
 194                                 enqueued and <command>systemctl</command> will
 195                                 wait until it is completed. By passing this
 196                                 argument it is only verified and
 197                                 enqueued.</para></listitem> </varlistentry>
 198
 199                         <varlistentry>
 200                                 <term><option>--no-pager</option></term>
 201
 202                                 <listitem><para>Do not pipe output into a
 203                                 pager.</para></listitem>
 204                         </varlistentry>
 205
 206                         <varlistentry>
 207                                 <term><option>--system</option></term>
 208
 209                                 <listitem><para>Talk to the systemd
 210                                 system manager. (Default)</para></listitem>
 211                         </varlistentry>
 212
 213                         <varlistentry>
 214                                 <term><option>--user</option></term>
 215
 216                                 <listitem><para>Talk to the systemd
 217                                 manager of the calling user.</para></listitem>
 218                         </varlistentry>
 219
 220                         <varlistentry>
 221                                 <term><option>--order</option></term>
 222                                 <term><option>--require</option></term>
 223
 224                                 <listitem><para>When used in
 225                                 conjunction with the
 226                                 <command>dot</command> command (see
 227                                 below), selects which dependencies are
 228                                 shown in the dependency graph. If
 229                                 <option>--order</option> is passed
 230                                 only dependencies of type
 231                                 <varname>After=</varname> or
 232                                 <varname>Before=</varname> are
 233                                 shown. If <option>--require</option>
 234                                 is passed only dependencies of type
 235                                 <varname>Requires=</varname>,
 236                                 <varname>RequiresOverridable=</varname>,
 237                                 <varname>Requisite=</varname>,
 238                                 <varname>RequisiteOverridable=</varname>,
 239                                 <varname>Wants=</varname> and
 240                                 <varname>Conflicts=</varname> are
 241                                 shown. If neither is passed, shows
 242                                 dependencies of all these
 243                                 types.</para></listitem>
 244                         </varlistentry>
 245
 246                         <varlistentry>
 247                                 <term><option>--no-wall</option></term>
 248
 249                                 <listitem><para>Don't send wall
 250                                 message before
 251                                 halt, power-off, reboot.</para></listitem>
 252                         </varlistentry>
 253
 254                         <varlistentry>
 255                                 <term><option>--global</option></term>
 256
 257                                 <listitem><para>When used with
 258                                 <command>enable</command> and
 259                                 <command>disable</command>, operate on the
 260                                 global user configuration
 261                                 directory, thus enabling or disabling
 262                                 a unit file globally for all future
 263                                 logins of all users.</para></listitem>
 264                         </varlistentry>
 265
 266                         <varlistentry>
 267                                 <term><option>--no-reload</option></term>
 268
 269                                 <listitem><para>When used with
 270                                 <command>enable</command> and
 271                                 <command>disable</command>, do not
 272                                 implicitly reload daemon configuration
 273                                 after executing the
 274                                 changes.</para></listitem>
 275                         </varlistentry>
 276
 277                         <varlistentry>
 278                                 <term><option>--no-ask-password</option></term>
 279
 280                                 <listitem><para>When used with
 281                                 <command>start</command> and related
 282                                 commands, disables asking for
 283                                 passwords. Background services may
 284                                 require input of a password or
 285                                 passphrase string, for example to
 286                                 unlock system hard disks or
 287                                 cryptographic certificates. Unless
 288                                 this option is specified and the
 289                                 command is invoked from a terminal
 290                                 <command>systemctl</command> will
 291                                 query the user on the terminal for the
 292                                 necessary secrets. Use this option to
 293                                 switch this behavior off. In this
 294                                 case the password must be supplied by
 295                                 some other means (for example
 296                                 graphical password agents) or the
 297                                 service might fail.</para></listitem>
 298                         </varlistentry>
 299
 300                         <varlistentry>
 301                                 <term><option>--kill-mode=</option></term>
 302
 303                                 <listitem><para>When used with
 304                                 <command>kill</command>, choose the
 305                                 mode how to kill the selected
 306                                 processes. Must be one of
 307                                 <option>control-group</option> or
 308                                 <option>process</option> to select
 309                                 whether to kill the entire control
 310                                 group or only the selected process
 311                                 itself. If omitted defaults to
 312                                 <option>control-group</option> if
 313                                 <option>--kill-who=all</option> is
 314                                 set, or <option>process</option>
 315                                 otherwise. You probably never need to
 316                                 use this switch.</para></listitem>
 317                         </varlistentry>
 318
 319                         <varlistentry>
 320                                 <term><option>--kill-who=</option></term>
 321
 322                                 <listitem><para>When used with
 323                                 <command>kill</command>, choose which
 324                                 processes to kill. Must be one of
 325                                 <option>main</option>,
 326                                 <option>control</option> or
 327                                 <option>all</option> to select whether
 328                                 to kill only the main process of the
 329                                 unit, the control process or all
 330                                 processes of the unit. If omitted
 331                                 defaults to
 332                                 <option>all</option>.</para></listitem>
 333                         </varlistentry>
 334
 335                         <varlistentry>
 336                                 <term><option>--signal=</option></term>
 337                                 <term><option>-s</option></term>
 338
 339                                 <listitem><para>When used with
 340                                 <command>kill</command>, choose which
 341                                 signal to send to selected
 342                                 processes. Must be one of the well
 343                                 known signal specifiers such as
 344                                 SIGTERM, SIGINT or SIGSTOP. If
 345                                 omitted defaults to
 346                                 <option>SIGTERM</option>.</para></listitem>
 347                         </varlistentry>
 348
 349                         <varlistentry>
 350                                 <term><option>--force</option></term>
 351                                 <term><option>-f</option></term>
 352
 353                                 <listitem><para>When used with
 354                                 <command>enable</command>, override any
 355                                 existing conflicting
 356                                 symlinks.</para></listitem>
 357
 358                                 <listitem><para>When used with
 359                                 <command>halt</command>,
 360                                 <command>poweroff</command>,
 361                                 <command>reboot</command> or
 362                                 <command>kexec</command> execute
 363                                 selected operation without shutting
 364                                 down all units. However, all processes
 365                                 will be killed forcibly and all file
 366                                 systems are unmounted or remounted
 367                                 read-only. This is hence a drastic but
 368                                 relatively safe option to request an
 369                                 immediate reboot.</para></listitem>
 370                         </varlistentry>
 371
 372                         <varlistentry>
 373                                 <term><option>--defaults</option></term>
 374
 375                                 <listitem><para>When used with
 376                                 <command>disable</command>, ensures
 377                                 that only the symlinks created by
 378                                 <command>enable</command> are removed,
 379                                 not all symlinks pointing to the unit
 380                                 file that shall be
 381                                 disabled.</para></listitem>
 382                         </varlistentry>
 383
 384                         <varlistentry>
 385                                 <term><option>-H</option></term>
 386                                 <term><option>--host</option></term>
 387
 388                                 <listitem><para>Execute operation
 389                                 remotely. Specifiy a hostname, or
 390                                 username and hostname seperated by @,
 391                                 to connect to. This will use SSH to
 392                                 talk to the remote systemd
 393                                 instance.</para></listitem>
 394                         </varlistentry>
 395
 396                         <varlistentry>
 397                                 <term><option>-P</option></term>
 398                                 <term><option>--privileged</option></term>
 399
 400                                 <listitem><para>Acquire privileges via
 401                                 PolicyKit before executing the
 402                                 operation.</para></listitem>
 403                         </varlistentry>
 404                 </variablelist>
 405
 406                 <para>The following commands are understood:</para>
 407
 408                 <variablelist>
 409                         <varlistentry>
 410                                 <term><command>list-units</command></term>
 411
 412                                 <listitem><para>List known units.</para></listitem>
 413                         </varlistentry>
 414                         <varlistentry>
 415                                 <term><command>start [NAME...]</command></term>
 416
 417                                 <listitem><para>Start (activate) one
 418                                 or more units specified on the command
 419                                 line.</para></listitem>
 420                         </varlistentry>
 421                         <varlistentry>
 422                                 <term><command>stop [NAME...]</command></term>
 423
 424                                 <listitem><para>Stop (deactivate) one
 425                                 or more units specified on the command
 426                                 line.</para></listitem>
 427                         </varlistentry>
 428                         <varlistentry>
 429                                 <term><command>reload [NAME...]</command></term>
 430
 431                                 <listitem><para>Asks all units listed
 432                                 on the command line to reload their
 433                                 configuration. Note that this will
 434                                 reload the service-specific
 435                                 configuration, not the unit
 436                                 configuration file of systemd. If you
 437                                 want systemd to reload the
 438                                 configuration file of a unit use the
 439                                 <command>daemon-reload</command>
 440                                 command. In other words: for the
 441                                 example case of Apache, this will
 442                                 reload Apache's
 443                                 <filename>httpd.conf</filename> in the
 444                                 web server, not the
 445                                 <filename>apache.service</filename>
 446                                 systemd unit file. </para>
 447
 448                                 <para>This command should not be
 449                                 confused with the
 450                                 <command>daemon-reload</command> or
 451                                 <command>load</command>
 452                                 commands.</para></listitem>
 453
 454                         </varlistentry>
 455                         <varlistentry>
 456                                 <term><command>restart [NAME...]</command></term>
 457
 458                                 <listitem><para>Restart one or more
 459                                 units specified on the command
 460                                 line. If the units are not running yet
 461                                 they will be
 462                                 started.</para></listitem>
 463                         </varlistentry>
 464                         <varlistentry>
 465                                 <term><command>try-restart [NAME...]</command></term>
 466
 467                                 <listitem><para>Restart one or more
 468                                 units specified on the command
 469                                 line if the units are running. Do
 470                                 nothing if units are not running.
 471                                 Note that for compatibility
 472                                 with Red Hat init scripts
 473                                 <command>condrestart</command> is
 474                                 equivalent to this command.</para></listitem>
 475                         </varlistentry>
 476                         <varlistentry>
 477                                 <term><command>reload-or-restart [NAME...]</command></term>
 478
 479                                 <listitem><para>Reload one or more
 480                                 units if they support it. If not,
 481                                 restart them instead. If the units
 482                                 are not running yet they will be
 483                                 started.</para></listitem>
 484                         </varlistentry>
 485                         <varlistentry>
 486                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 487
 488                                 <listitem><para>Reload one or more
 489                                 units if they support it. If not,
 490                                 restart them instead. If the units
 491                                 are not running yet the operation
 492                                 will fail. Note that for
 493                                 compatibility with SysV init scripts
 494                                 <command>force-reload</command> is
 495                                 equivalent to this command.</para></listitem>
 496                         </varlistentry>
 497                         <varlistentry>
 498                                 <term><command>isolate [NAME]</command></term>
 499
 500                                 <listitem><para>Start the unit
 501                                 specified on the command line and its
 502                                 dependencies and stop all others.</para>
 503
 504                                 <para>This is similar to changing the
 505                                 runlevel in a traditional init system. The
 506                                 <command>isolate</command> command will
 507                                 immediately stop processes that are not
 508                                 enabled in the new unit, possibly including
 509                                 the graphical environment or terminal you
 510                                 are currently using.</para>
 511
 512                                 <para>Note that this works only on units
 513                                 where <option>AllowIsolate=</option> is
 514                                 enabled. See
 515                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 516                                 for details.</para></listitem>
 517                         </varlistentry>
 518                         <varlistentry>
 519                                 <term><command>kill [NAME...]</command></term>
 520
 521                                 <listitem><para>Send a signal to one
 522                                 or more processes of the unit. Use
 523                                 <option>--kill-who=</option> to select
 524                                 which process to kill. Use
 525                                 <option>--kill-mode=</option> to
 526                                 select the kill mode and
 527                                 <option>--signal=</option> to select
 528                                 the signal to send.</para></listitem>
 529                         </varlistentry>
 530                         <varlistentry>
 531                                 <term><command>is-active [NAME...]</command></term>
 532
 533                                 <listitem><para>Check whether any of
 534                                 the specified units are active
 535                                 (i.e. running). Returns an exit code
 536                                 0 if at least one is active, non-zero
 537                                 otherwise. Unless
 538                                 <option>--quiet</option> is specified
 539                                 this will also print the current unit
 540                                 state to STDOUT.</para></listitem>
 541                         </varlistentry>
 542                         <varlistentry>
 543                                 <term><command>status [NAME...|PID...]</command></term>
 544
 545                                 <listitem><para>Show terse runtime
 546                                 status information about one or more
 547                                 units. This function is intended to
 548                                 generate human-readable output. If you
 549                                 are looking for computer-parsable
 550                                 output, use <command>show</command>
 551                                 instead. If a PID is passed
 552                                 information about the unit the process
 553                                 of the PID belongs to is
 554                                 shown.</para></listitem>
 555                         </varlistentry>
 556                         <varlistentry>
 557                                 <term><command>show [NAME...|JOB...]</command></term>
 558
 559                                 <listitem><para>Show properties of one
 560                                 or more units, jobs or the manager
 561                                 itself. If no argument is specified
 562                                 properties of the manager will be
 563                                 shown. If a unit name is specified
 564                                 properties of the unit is shown, and
 565                                 if a job id is specified properties of
 566                                 the job is shown. By default, empty
 567                                 properties are suppressed. Use
 568                                 <option>--all</option> to show those
 569                                 too. To select specific properties to
 570                                 show use
 571                                 <option>--property=</option>. This
 572                                 command is intended to be used
 573                                 whenever computer-parsable output is
 574                                 required. Use
 575                                 <command>status</command> if you are
 576                                 looking for formatted human-readable
 577                                 output.</para></listitem>
 578                         </varlistentry>
 579
 580                         <varlistentry>
 581                                 <term><command>reset-failed [NAME...]</command></term>
 582
 583                                 <listitem><para>Reset the
 584                                 '<literal>failed</literal>' state of the
 585                                 specified units, or if no unit name is
 586                                 passed of all units. When a unit fails
 587                                 in some way (i.e. process exiting with
 588                                 non-zero error code, terminating
 589                                 abnormally or timing out) it will
 590                                 automatically enter the
 591                                 '<literal>failed</literal>' state and
 592                                 its exit code and status is recorded
 593                                 for introspection by the administrator
 594                                 until the service is restarted or
 595                                 reset with this
 596                                 command.</para></listitem>
 597                         </varlistentry>
 598
 599                         <varlistentry>
 600                                 <term><command>enable [NAME...]</command></term>
 601
 602                                 <listitem><para>Enable one or more
 603                                 unit files, as specified on the
 604                                 command line. This will create a
 605                                 number of symlinks as encoded in the
 606                                 <literal>[Install]</literal> sections
 607                                 of the unit files. After the symlinks
 608                                 have been created the systemd
 609                                 configuration is reloaded (in a way
 610                                 that is equivalent to
 611                                 <command>daemon-reload</command>) to
 612                                 ensure the changes are taken into
 613                                 account immediately. Note that this
 614                                 does not have the effect that any of
 615                                 the units enabled are also started at
 616                                 the same time. If this is desired a
 617                                 separate <command>start</command>
 618                                 command must be invoked for the
 619                                 unit.</para>
 620
 621                                 <para>This command will
 622                                 print the actions executed. This
 623                                 output may be suppressed by passing
 624                                 <option>--quiet</option>.</para>
 625
 626                                 <para>Note that this operation creates
 627                                 only the suggested symlinks for the
 628                                 units. While this command is the
 629                                 recommended way to manipulate the unit
 630                                 configuration directory, the
 631                                 administrator is free to make
 632                                 additional changes manually, by
 633                                 placing or removing symlinks in the
 634                                 directory. This is particularly useful
 635                                 to create configurations that deviate
 636                                 from the suggested default
 637                                 installation. In this case the
 638                                 administrator must make sure to invoke
 639                                 <command>daemon-reload</command>
 640                                 manually as necessary, to ensure his
 641                                 changes are taken into account.</para>
 642
 643                                 <para>Enabling units should not be
 644                                 confused with starting (activating)
 645                                 units, as done by the
 646                                 <command>start</command>
 647                                 command. Enabling and starting units
 648                                 is orthogonal: units may be enabled
 649                                 without being started and started
 650                                 without being enabled. Enabling simply
 651                                 hooks the unit into various suggested
 652                                 places (for example, so that the unit
 653                                 is automatically started on boot or
 654                                 when a particular kind of hardware is
 655                                 plugged in). Starting actually spawns
 656                                 the daemon process (in case of service
 657                                 units), or binds the socket (in case
 658                                 of socket units), and so
 659                                 on.</para>
 660
 661                                 <para>Depending on whether
 662                                 <option>--system</option>,
 663                                 <option>--user</option> or
 664                                 <option>--global</option> is specified
 665                                 this enables the unit for the system,
 666                                 for the calling user only
 667                                 or for all future logins of all
 668                                 users. Note that in the latter case no
 669                                 systemd daemon configuration is
 670                                 reloaded.</para>
 671                                 </listitem>
 672                         </varlistentry>
 673
 674                         <varlistentry>
 675                                 <term><command>disable [NAME...]</command></term>
 676
 677                                 <listitem><para>Disables one or more
 678                                 units. This removes all symlinks to
 679                                 the specified unit files from the unit
 680                                 configuration directory, and hence
 681                                 undoes the changes made by
 682                                 <command>enable</command>. Note
 683                                 however that this by default removes
 684                                 all symlinks to the unit files
 685                                 (i.e. including manual additions), not
 686                                 just those actually created by
 687                                 <command>enable</command>. If only the
 688                                 symlinks that are suggested by default
 689                                 shall be removed, pass
 690                                 <option>--defaults</option>. This
 691                                 implicitly reloads the systemd daemon
 692                                 configuration after completing the
 693                                 disabling of the units. Note that this
 694                                 command does not implicitly stop the
 695                                 units that is being disabled. If this
 696                                 is desired an additional
 697                                 <command>stop</command>command should
 698                                 be executed afterwards.</para>
 699
 700                                 <para>This command will print the
 701                                 actions executed. This output may be
 702                                 suppressed by passing
 703                                 <option>--quiet</option>.</para>
 704                                 </listitem>
 705
 706                                 <para>This command honors
 707                                 <option>--system</option>,
 708                                 <option>--user</option>,
 709                                 <option>--global</option> in a similar
 710                                 way as
 711                                 <command>enable</command>.</para>
 712                         </varlistentry>
 713
 714                         <varlistentry>
 715                                 <term><command>is-enabled [NAME...]</command></term>
 716
 717                                 <listitem><para>Checks whether any of
 718                                 the specified unit files is enabled
 719                                 (as with
 720                                 <command>enable</command>). Returns an
 721                                 exit code of 0 if at least one is
 722                                 enabled, non-zero
 723                                 otherwise.</para></listitem>
 724                         </varlistentry>
 725
 726                         <varlistentry>
 727                                 <term><command>load [NAME...]</command></term>
 728
 729                                 <listitem><para>Load one or more units
 730                                 specified on the command line. This
 731                                 will simply load their configuration
 732                                 from disk, but not start them. To
 733                                 start them you need to use the
 734                                 <command>start</command> command which
 735                                 will implicitly load a unit that has
 736                                 not been loaded yet. Note that systemd
 737                                 garbage collects loaded units that are
 738                                 not active or referenced by an active
 739                                 unit. This means that units loaded
 740                                 this way will usually not stay loaded
 741                                 for long. Also note that this command
 742                                 cannot be used to reload unit
 743                                 configuration. Use the
 744                                 <command>daemon-reload</command>
 745                                 command for that. All in all, this
 746                                 command is of little use except for
 747                                 debugging.</para>
 748                                 <para>This command should not be
 749                                 confused with the
 750                                 <command>daemon-reload</command> or
 751                                 <command>reload</command>
 752                                 commands.</para></listitem>
 753                         </varlistentry>
 754                         <varlistentry>
 755                                 <term><command>list-jobs</command></term>
 756
 757                                 <listitem><para>List jobs that are in progress.</para></listitem>
 758                         </varlistentry>
 759                         <varlistentry>
 760                                 <term><command>cancel [JOB...]</command></term>
 761
 762                                 <listitem><para>Cancel one or more
 763                                 jobs specified on the command line by
 764                                 their numeric job
 765                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 766                         </varlistentry>
 767                         <varlistentry>
 768                                 <term><command>monitor</command></term>
 769
 770                                 <listitem><para>Monitor unit/job
 771                                 changes. This is mostly useful for
 772                                 debugging purposes and prints a line
 773                                 each time systemd loads or unloads a
 774                                 unit configuration file, or a unit
 775                                 property changes.</para></listitem>
 776                         </varlistentry>
 777                         <varlistentry>
 778                                 <term><command>dump</command></term>
 779
 780                                 <listitem><para>Dump server
 781                                 status. This will output a (usually
 782                                 very long) human readable manager
 783                                 status dump. Its format is subject to
 784                                 change without notice and should not
 785                                 be parsed by
 786                                 applications.</para></listitem>
 787                         </varlistentry>
 788                         <varlistentry>
 789                                 <term><command>dot</command></term>
 790
 791                                 <listitem><para>Generate textual
 792                                 dependency graph description in dot
 793                                 format for further processing with the
 794                                 GraphViz
 795                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 796                                 tool. Use a command line like
 797                                 <command>systemctl dot | dot -Tsvg >
 798                                 systemd.svg</command> to generate a
 799                                 graphical dependency tree. Unless
 800                                 <option>--order</option> or
 801                                 <option>--require</option> is passed
 802                                 the generated graph will show both
 803                                 ordering and requirement
 804                                 dependencies.</para></listitem>
 805                         </varlistentry>
 806                         <varlistentry>
 807                                 <term><command>snapshot [NAME]</command></term>
 808
 809                                 <listitem><para>Create a snapshot. If
 810                                 a snapshot name is specified, the new
 811                                 snapshot will be named after it. If
 812                                 none is specified an automatic
 813                                 snapshot name is generated. In either
 814                                 case, the snapshot name used is
 815                                 printed to STDOUT, unless
 816                                 <option>--quiet</option> is
 817                                 specified.</para>
 818
 819                                 <para>A snapshot refers to a saved
 820                                 state of the systemd manager. It is
 821                                 implemented itself as a unit that is
 822                                 generated dynamically with this
 823                                 command and has dependencies on all
 824                                 units active at the time. At a later
 825                                 time the user may return to this state
 826                                 by using the
 827                                 <command>isolate</command> command on
 828                                 the snapshot unit.</para></listitem>
 829
 830                                 <para>Snapshots are only useful for
 831                                 saving and restoring which units are
 832                                 running or are stopped, they do not
 833                                 save/restore any other
 834                                 state. Snapshots are dynamic and lost
 835                                 on reboot.</para>
 836                         </varlistentry>
 837                         <varlistentry>
 838                                 <term><command>delete [NAME...]</command></term>
 839
 840                                 <listitem><para>Remove a snapshot
 841                                 previously created with
 842                                 <command>snapshot</command>.</para></listitem>
 843                         </varlistentry>
 844                         <varlistentry>
 845                                 <term><command>daemon-reload</command></term>
 846
 847                                 <listitem><para>Reload systemd manager
 848                                 configuration. This will reload all
 849                                 unit files and recreate the entire
 850                                 dependency tree. While the daemon is
 851                                 reloaded, all sockets systemd listens
 852                                 on on behalf of user configuration will
 853                                 stay accessible.</para> <para>This
 854                                 command should not be confused with
 855                                 the <command>load</command> or
 856                                 <command>reload</command>
 857                                 commands.</para></listitem>
 858                         </varlistentry>
 859                         <varlistentry>
 860                                 <term><command>daemon-reexec</command></term>
 861
 862                                 <listitem><para>Reexecute the systemd
 863                                 manager. This will serialize the
 864                                 manager state, reexecute the process
 865                                 and deserialize the state again. This
 866                                 command is of little use except for
 867                                 debugging and package
 868                                 upgrades. Sometimes it might be
 869                                 helpful as a heavy-weight
 870                                 <command>daemon-reload</command>. While
 871                                 the daemon is reexecuted all sockets
 872                                 systemd listens on on behalf of user
 873                                 configuration will stay
 874                                 accessible.</para></listitem>
 875                         </varlistentry>
 876                         <varlistentry>
 877                                 <term><command>show-environment</command></term>
 878
 879                                 <listitem><para>Dump the systemd
 880                                 manager environment block. The
 881                                 environment block will be dumped in
 882                                 straight-forward form suitable for
 883                                 sourcing into a shell script. This
 884                                 environment block will be passed to
 885                                 all processes the manager
 886                                 spawns.</para></listitem>
 887                         </varlistentry>
 888                         <varlistentry>
 889                                 <term><command>set-environment [NAME=VALUE...]</command></term>
 890
 891                                 <listitem><para>Set one or more
 892                                 systemd manager environment variables,
 893                                 as specified on the command
 894                                 line.</para></listitem>
 895                         </varlistentry>
 896                         <varlistentry>
 897                                 <term><command>unset-environment [NAME...]</command></term>
 898
 899                                 <listitem><para>Unset one or more
 900                                 systemd manager environment
 901                                 variables. If only a variable name is
 902                                 specified it will be removed
 903                                 regardless of its value. If a variable
 904                                 and a value are specified the variable
 905                                 is only removed if it has the
 906                                 specified value.</para></listitem>
 907                         </varlistentry>
 908                         <varlistentry>
 909                                 <term><command>default</command></term>
 910
 911                                 <listitem><para>Enter default
 912                                 mode. This is mostly equivalent to
 913                                 <command>start
 914                                 default.target</command>.</para></listitem>
 915                         </varlistentry>
 916                         <varlistentry>
 917                                 <term><command>rescue</command></term>
 918
 919                                 <listitem><para>Enter rescue
 920                                 mode. This is mostly equivalent to
 921                                 <command>isolate
 922                                 rescue.target</command> but also
 923                                 prints a wall message to all
 924                                 users.</para></listitem>
 925                         </varlistentry>
 926                         <varlistentry>
 927                                 <term><command>emergency</command></term>
 928
 929                                 <listitem><para>Enter emergency
 930                                 mode. This is mostly equivalent to
 931                                 <command>isolate
 932                                 emergency.target</command> but also
 933                                 prints a wall message to all
 934                                 users.</para></listitem>
 935                         </varlistentry>
 936                         <varlistentry>
 937                                 <term><command>halt</command></term>
 938
 939                                 <listitem><para>Shut down and halt the
 940                                 system. This is mostly equivalent to
 941                                 <command>start halt.target</command>
 942                                 but also prints a wall message to all
 943                                 users.  If
 944                                 combined with <option>--force</option>
 945                                 shutdown of all running services is
 946                                 skipped, however all processes are killed
 947                                 and all file systems are unmounted or
 948                                 mounted read-only, immediately
 949                                 followed by the
 950                                 system halt.</para></listitem>
 951                         </varlistentry>
 952                         <varlistentry>
 953                                 <term><command>poweroff</command></term>
 954
 955                                 <listitem><para>Shut down and
 956                                 power-off the system. This is mostly
 957                                 equivalent to <command>start
 958                                 poweroff.target</command> but also
 959                                 prints a wall message to all
 960                                 users. If
 961                                 combined with <option>--force</option>
 962                                 shutdown of all running services is
 963                                 skipped, however all processes are killed
 964                                 and all file systems are unmounted or
 965                                 mounted read-only, immediately
 966                                 followed by the
 967                                 powering off.</para></listitem>
 968                         </varlistentry>
 969                         <varlistentry>
 970                                 <term><command>reboot</command></term>
 971
 972                                 <listitem><para>Shut down and
 973                                 reboot the system. This is mostly
 974                                 equivalent to <command>start
 975                                 reboot.target</command> but also
 976                                 prints a wall message to all
 977                                 users. If
 978                                 combined with <option>--force</option>
 979                                 shutdown of all running services is
 980                                 skipped, however all processes are killed
 981                                 and all file systems are unmounted or
 982                                 mounted read-only, immediately
 983                                 followed by the
 984                                 reboot.</para></listitem>
 985                         </varlistentry>
 986                         <varlistentry>
 987                                 <term><command>kexec</command></term>
 988
 989                                 <listitem><para>Shut down and reboot
 990                                 the system via kexec. This is mostly
 991                                 equivalent to <command>start
 992                                 kexec.target</command> but also prints
 993                                 a wall message to all users. If
 994                                 combined with <option>--force</option>
 995                                 shutdown of all running services is
 996                                 skipped, however all processes are killed
 997                                 and all file systems are unmounted or
 998                                 mounted read-only, immediately
 999                                 followed by the
1000                                 reboot.</para></listitem>
1001                         </varlistentry>
1002                         <varlistentry>
1003                                 <term><command>exit</command></term>
1004
1005                                 <listitem><para>Ask the systemd
1006                                 manager to quit. This is only
1007                                 supported for user service managers
1008                                 (i.e. in conjunction with the
1009                                 <option>--user</option> option) and
1010                                 will fail otherwise.</para></listitem>
1011                         </varlistentry>
1012                 </variablelist>
1013
1014         </refsect1>
1015
1016         <refsect1>
1017                 <title>Exit status</title>
1018
1019                 <para>On success 0 is returned, a non-zero failure
1020                 code otherwise.</para>
1021         </refsect1>
1022
1023         <refsect1>
1024                 <title>See Also</title>
1025                 <para>
1026                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1027                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1028                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1029                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1030                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1031                 </para>
1032         </refsect1>
1033
1034 </refentry>