man/systemctl.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   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
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  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/>.
  22 -->
  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 properties, 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 properties,
 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>
 198                         </varlistentry>
 199
 200                         <varlistentry>
 201                                 <term><option>--no-legend</option></term>
 202
 203                                 <listitem><para>Do not print a legend, i.e.
 204                                 the column headers and the footer with hints.
 205                                 </para></listitem>
 206                         </varlistentry>
 207
 208                         <varlistentry>
 209                                 <term><option>--no-pager</option></term>
 210
 211                                 <listitem><para>Do not pipe output into a
 212                                 pager.</para></listitem>
 213                         </varlistentry>
 214
 215                         <varlistentry>
 216                                 <term><option>--system</option></term>
 217
 218                                 <listitem><para>Talk to the systemd
 219                                 system manager. (Default)</para></listitem>
 220                         </varlistentry>
 221
 222                         <varlistentry>
 223                                 <term><option>--user</option></term>
 224
 225                                 <listitem><para>Talk to the systemd
 226                                 manager of the calling user.</para></listitem>
 227                         </varlistentry>
 228
 229                         <varlistentry>
 230                                 <term><option>--order</option></term>
 231                                 <term><option>--require</option></term>
 232
 233                                 <listitem><para>When used in
 234                                 conjunction with the
 235                                 <command>dot</command> command (see
 236                                 below), selects which dependencies are
 237                                 shown in the dependency graph. If
 238                                 <option>--order</option> is passed
 239                                 only dependencies of type
 240                                 <varname>After=</varname> or
 241                                 <varname>Before=</varname> are
 242                                 shown. If <option>--require</option>
 243                                 is passed only dependencies of type
 244                                 <varname>Requires=</varname>,
 245                                 <varname>RequiresOverridable=</varname>,
 246                                 <varname>Requisite=</varname>,
 247                                 <varname>RequisiteOverridable=</varname>,
 248                                 <varname>Wants=</varname> and
 249                                 <varname>Conflicts=</varname> are
 250                                 shown. If neither is passed, shows
 251                                 dependencies of all these
 252                                 types.</para></listitem>
 253                         </varlistentry>
 254
 255                         <varlistentry>
 256                                 <term><option>--no-wall</option></term>
 257
 258                                 <listitem><para>Don't send wall
 259                                 message before
 260                                 halt, power-off, reboot.</para></listitem>
 261                         </varlistentry>
 262
 263                         <varlistentry>
 264                                 <term><option>--global</option></term>
 265
 266                                 <listitem><para>When used with
 267                                 <command>enable</command> and
 268                                 <command>disable</command>, operate on the
 269                                 global user configuration
 270                                 directory, thus enabling or disabling
 271                                 a unit file globally for all future
 272                                 logins of all users.</para></listitem>
 273                         </varlistentry>
 274
 275                         <varlistentry>
 276                                 <term><option>--no-reload</option></term>
 277
 278                                 <listitem><para>When used with
 279                                 <command>enable</command> and
 280                                 <command>disable</command>, do not
 281                                 implicitly reload daemon configuration
 282                                 after executing the
 283                                 changes.</para></listitem>
 284                         </varlistentry>
 285
 286                         <varlistentry>
 287                                 <term><option>--no-ask-password</option></term>
 288
 289                                 <listitem><para>When used with
 290                                 <command>start</command> and related
 291                                 commands, disables asking for
 292                                 passwords. Background services may
 293                                 require input of a password or
 294                                 passphrase string, for example to
 295                                 unlock system hard disks or
 296                                 cryptographic certificates. Unless
 297                                 this option is specified and the
 298                                 command is invoked from a terminal
 299                                 <command>systemctl</command> will
 300                                 query the user on the terminal for the
 301                                 necessary secrets. Use this option to
 302                                 switch this behavior off. In this
 303                                 case the password must be supplied by
 304                                 some other means (for example
 305                                 graphical password agents) or the
 306                                 service might fail.</para></listitem>
 307                         </varlistentry>
 308
 309                         <varlistentry>
 310                                 <term><option>--kill-who=</option></term>
 311
 312                                 <listitem><para>When used with
 313                                 <command>kill</command>, choose which
 314                                 processes to kill. Must be one of
 315                                 <option>main</option>,
 316                                 <option>control</option> or
 317                                 <option>all</option> to select whether
 318                                 to kill only the main process of the
 319                                 unit, the control process or all
 320                                 processes of the unit. If omitted
 321                                 defaults to
 322                                 <option>all</option>.</para></listitem>
 323                         </varlistentry>
 324
 325                         <varlistentry>
 326                                 <term><option>--signal=</option></term>
 327                                 <term><option>-s</option></term>
 328
 329                                 <listitem><para>When used with
 330                                 <command>kill</command>, choose which
 331                                 signal to send to selected
 332                                 processes. Must be one of the well
 333                                 known signal specifiers such as
 334                                 SIGTERM, SIGINT or SIGSTOP. If
 335                                 omitted defaults to
 336                                 <option>SIGTERM</option>.</para></listitem>
 337                         </varlistentry>
 338
 339                         <varlistentry>
 340                                 <term><option>--force</option></term>
 341                                 <term><option>-f</option></term>
 342
 343                                 <listitem><para>When used with
 344                                 <command>enable</command>, override any
 345                                 existing conflicting
 346                                 symlinks.</para></listitem>
 347
 348                                 <listitem><para>When used with
 349                                 <command>halt</command>,
 350                                 <command>poweroff</command>,
 351                                 <command>reboot</command> or
 352                                 <command>kexec</command> execute
 353                                 selected operation without shutting
 354                                 down all units. However, all processes
 355                                 will be killed forcibly and all file
 356                                 systems are unmounted or remounted
 357                                 read-only. This is hence a drastic but
 358                                 relatively safe option to request an
 359                                 immediate reboot.</para></listitem>
 360                         </varlistentry>
 361
 362                         <varlistentry>
 363                                 <term><option>--root=</option></term>
 364
 365                                 <listitem><para>When used with
 366                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and
 367                                 related commands), use alternative
 368                                 root path when looking for unit
 369                                 files.</para></listitem>
 370                         </varlistentry>
 371
 372                         <varlistentry>
 373                                 <term><option>--runtime</option></term>
 374
 375                                 <listitem><para>When used with
 376                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and related commands), make
 377                                 changes only temporarily, so that they
 378                                 are dropped on the next reboot. This
 379                                 will have the effect that changes are
 380                                 not made in subdirectories of
 381                                 <filename>/etc</filename> but in
 382                                 <filename>/run</filename>, with
 383                                 identical immediate effects, however,
 384                                 since the latter is lost on reboot,
 385                                 the changes are lost
 386                                 too.</para></listitem>
 387                         </varlistentry>
 388
 389                         <varlistentry>
 390                                 <term><option>-H</option></term>
 391                                 <term><option>--host</option></term>
 392
 393                                 <listitem><para>Execute operation
 394                                 remotely. Specify a hostname, or
 395                                 username and hostname separated by @,
 396                                 to connect to. This will use SSH to
 397                                 talk to the remote systemd
 398                                 instance.</para></listitem>
 399                         </varlistentry>
 400
 401                         <varlistentry>
 402                                 <term><option>-P</option></term>
 403                                 <term><option>--privileged</option></term>
 404
 405                                 <listitem><para>Acquire privileges via
 406                                 PolicyKit before executing the
 407                                 operation.</para></listitem>
 408                         </varlistentry>
 409                 </variablelist>
 410
 411                 <para>The following commands are understood:</para>
 412
 413                 <variablelist>
 414                         <varlistentry>
 415                                 <term><command>list-units</command></term>
 416
 417                                 <listitem><para>List known units.</para></listitem>
 418                         </varlistentry>
 419                         <varlistentry>
 420                                 <term><command>start [NAME...]</command></term>
 421
 422                                 <listitem><para>Start (activate) one
 423                                 or more units specified on the command
 424                                 line.</para></listitem>
 425                         </varlistentry>
 426                         <varlistentry>
 427                                 <term><command>stop [NAME...]</command></term>
 428
 429                                 <listitem><para>Stop (deactivate) one
 430                                 or more units specified on the command
 431                                 line.</para></listitem>
 432                         </varlistentry>
 433                         <varlistentry>
 434                                 <term><command>reload [NAME...]</command></term>
 435
 436                                 <listitem><para>Asks all units listed
 437                                 on the command line to reload their
 438                                 configuration. Note that this will
 439                                 reload the service-specific
 440                                 configuration, not the unit
 441                                 configuration file of systemd. If you
 442                                 want systemd to reload the
 443                                 configuration file of a unit use the
 444                                 <command>daemon-reload</command>
 445                                 command. In other words: for the
 446                                 example case of Apache, this will
 447                                 reload Apache's
 448                                 <filename>httpd.conf</filename> in the
 449                                 web server, not the
 450                                 <filename>apache.service</filename>
 451                                 systemd unit file. </para>
 452
 453                                 <para>This command should not be
 454                                 confused with the
 455                                 <command>daemon-reload</command> or
 456                                 <command>load</command>
 457                                 commands.</para></listitem>
 458
 459                         </varlistentry>
 460                         <varlistentry>
 461                                 <term><command>restart [NAME...]</command></term>
 462
 463                                 <listitem><para>Restart one or more
 464                                 units specified on the command
 465                                 line. If the units are not running yet
 466                                 they will be
 467                                 started.</para></listitem>
 468                         </varlistentry>
 469                         <varlistentry>
 470                                 <term><command>try-restart [NAME...]</command></term>
 471
 472                                 <listitem><para>Restart one or more
 473                                 units specified on the command
 474                                 line if the units are running. Do
 475                                 nothing if units are not running.
 476                                 Note that for compatibility
 477                                 with Red Hat init scripts
 478                                 <command>condrestart</command> is
 479                                 equivalent to this command.</para></listitem>
 480                         </varlistentry>
 481                         <varlistentry>
 482                                 <term><command>reload-or-restart [NAME...]</command></term>
 483
 484                                 <listitem><para>Reload one or more
 485                                 units if they support it. If not,
 486                                 restart them instead. If the units
 487                                 are not running yet they will be
 488                                 started.</para></listitem>
 489                         </varlistentry>
 490                         <varlistentry>
 491                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 492
 493                                 <listitem><para>Reload one or more
 494                                 units if they support it. If not,
 495                                 restart them instead. Do nothing if
 496                                 the units are not running. Note that
 497                                 for compatibility with SysV init
 498                                 scripts
 499                                 <command>force-reload</command> is
 500                                 equivalent to this
 501                                 command.</para></listitem>
 502                         </varlistentry>
 503                         <varlistentry>
 504                                 <term><command>isolate [NAME]</command></term>
 505
 506                                 <listitem><para>Start the unit
 507                                 specified on the command line and its
 508                                 dependencies and stop all others.</para>
 509
 510                                 <para>This is similar to changing the
 511                                 runlevel in a traditional init system. The
 512                                 <command>isolate</command> command will
 513                                 immediately stop processes that are not
 514                                 enabled in the new unit, possibly including
 515                                 the graphical environment or terminal you
 516                                 are currently using.</para>
 517
 518                                 <para>Note that this works only on units
 519                                 where <option>AllowIsolate=</option> is
 520                                 enabled. See
 521                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 522                                 for details.</para></listitem>
 523                         </varlistentry>
 524                         <varlistentry>
 525                                 <term><command>kill [NAME...]</command></term>
 526
 527                                 <listitem><para>Send a signal to one
 528                                 or more processes of the unit. Use
 529                                 <option>--kill-who=</option> to select
 530                                 which process to kill. Use
 531                                 <option>--kill-mode=</option> to
 532                                 select the kill mode and
 533                                 <option>--signal=</option> to select
 534                                 the signal to send.</para></listitem>
 535                         </varlistentry>
 536                         <varlistentry>
 537                                 <term><command>is-active [NAME...]</command></term>
 538
 539                                 <listitem><para>Check whether any of
 540                                 the specified units are active
 541                                 (i.e. running). Returns an exit code
 542                                 0 if at least one is active, non-zero
 543                                 otherwise. Unless
 544                                 <option>--quiet</option> is specified
 545                                 this will also print the current unit
 546                                 state to STDOUT.</para></listitem>
 547                         </varlistentry>
 548                         <varlistentry>
 549                                 <term><command>status [NAME...|PID...]</command></term>
 550
 551                                 <listitem><para>Show terse runtime
 552                                 status information about one or more
 553                                 units. This function is intended to
 554                                 generate human-readable output. If you
 555                                 are looking for computer-parsable
 556                                 output, use <command>show</command>
 557                                 instead. If a PID is passed
 558                                 information about the unit the process
 559                                 of the PID belongs to is
 560                                 shown.</para></listitem>
 561                         </varlistentry>
 562                         <varlistentry>
 563                                 <term><command>show [NAME...|JOB...]</command></term>
 564
 565                                 <listitem><para>Show properties of one
 566                                 or more units, jobs or the manager
 567                                 itself. If no argument is specified
 568                                 properties of the manager will be
 569                                 shown. If a unit name is specified
 570                                 properties of the unit is shown, and
 571                                 if a job id is specified properties of
 572                                 the job is shown. By default, empty
 573                                 properties are suppressed. Use
 574                                 <option>--all</option> to show those
 575                                 too. To select specific properties to
 576                                 show use
 577                                 <option>--property=</option>. This
 578                                 command is intended to be used
 579                                 whenever computer-parsable output is
 580                                 required. Use
 581                                 <command>status</command> if you are
 582                                 looking for formatted human-readable
 583                                 output.</para></listitem>
 584                         </varlistentry>
 585
 586                         <varlistentry>
 587                                 <term><command>reset-failed [NAME...]</command></term>
 588
 589                                 <listitem><para>Reset the
 590                                 '<literal>failed</literal>' state of the
 591                                 specified units, or if no unit name is
 592                                 passed of all units. When a unit fails
 593                                 in some way (i.e. process exiting with
 594                                 non-zero error code, terminating
 595                                 abnormally or timing out) it will
 596                                 automatically enter the
 597                                 '<literal>failed</literal>' state and
 598                                 its exit code and status is recorded
 599                                 for introspection by the administrator
 600                                 until the service is restarted or
 601                                 reset with this
 602                                 command.</para></listitem>
 603                         </varlistentry>
 604
 605                         <varlistentry>
 606                                 <term><command>enable [NAME...]</command></term>
 607
 608                                 <listitem><para>Enable one or more
 609                                 unit files, as specified on the
 610                                 command line. This will create a
 611                                 number of symlinks as encoded in the
 612                                 <literal>[Install]</literal> sections
 613                                 of the unit files. After the symlinks
 614                                 have been created the systemd
 615                                 configuration is reloaded (in a way
 616                                 that is equivalent to
 617                                 <command>daemon-reload</command>) to
 618                                 ensure the changes are taken into
 619                                 account immediately. Note that this
 620                                 does not have the effect that any of
 621                                 the units enabled are also started at
 622                                 the same time. If this is desired a
 623                                 separate <command>start</command>
 624                                 command must be invoked for the
 625                                 unit.</para>
 626
 627                                 <para>This command will
 628                                 print the actions executed. This
 629                                 output may be suppressed by passing
 630                                 <option>--quiet</option>.</para>
 631
 632                                 <para>Note that this operation creates
 633                                 only the suggested symlinks for the
 634                                 units. While this command is the
 635                                 recommended way to manipulate the unit
 636                                 configuration directory, the
 637                                 administrator is free to make
 638                                 additional changes manually, by
 639                                 placing or removing symlinks in the
 640                                 directory. This is particularly useful
 641                                 to create configurations that deviate
 642                                 from the suggested default
 643                                 installation. In this case the
 644                                 administrator must make sure to invoke
 645                                 <command>daemon-reload</command>
 646                                 manually as necessary, to ensure his
 647                                 changes are taken into account.</para>
 648
 649                                 <para>Enabling units should not be
 650                                 confused with starting (activating)
 651                                 units, as done by the
 652                                 <command>start</command>
 653                                 command. Enabling and starting units
 654                                 is orthogonal: units may be enabled
 655                                 without being started and started
 656                                 without being enabled. Enabling simply
 657                                 hooks the unit into various suggested
 658                                 places (for example, so that the unit
 659                                 is automatically started on boot or
 660                                 when a particular kind of hardware is
 661                                 plugged in). Starting actually spawns
 662                                 the daemon process (in case of service
 663                                 units), or binds the socket (in case
 664                                 of socket units), and so
 665                                 on.</para>
 666
 667                                 <para>Depending on whether
 668                                 <option>--system</option>,
 669                                 <option>--user</option> or
 670                                 <option>--global</option> is specified
 671                                 this enables the unit for the system,
 672                                 for the calling user only
 673                                 or for all future logins of all
 674                                 users. Note that in the latter case no
 675                                 systemd daemon configuration is
 676                                 reloaded.</para>
 677                                 </listitem>
 678                         </varlistentry>
 679
 680                         <varlistentry>
 681                                 <term><command>disable [NAME...]</command></term>
 682
 683                                 <listitem><para>Disables one or more
 684                                 units. This removes all symlinks to
 685                                 the specified unit files from the unit
 686                                 configuration directory, and hence
 687                                 undoes the changes made by
 688                                 <command>enable</command>. Note
 689                                 however that this removes
 690                                 all symlinks to the unit files
 691                                 (i.e. including manual additions), not
 692                                 just those actually created by
 693                                 <command>enable</command>. This call
 694                                 implicitly reloads the systemd daemon
 695                                 configuration after completing the
 696                                 disabling of the units. Note that this
 697                                 command does not implicitly stop the
 698                                 units that is being disabled. If this
 699                                 is desired an additional
 700                                 <command>stop</command>command should
 701                                 be executed afterwards.</para>
 702
 703                                 <para>This command will print the
 704                                 actions executed. This output may be
 705                                 suppressed by passing
 706                                 <option>--quiet</option>.</para>
 707                                 </listitem>
 708
 709                                 <para>This command honors
 710                                 <option>--system</option>,
 711                                 <option>--user</option>,
 712                                 <option>--global</option> in a similar
 713                                 way as
 714                                 <command>enable</command>.</para>
 715                         </varlistentry>
 716
 717                         <varlistentry>
 718                                 <term><command>is-enabled [NAME...]</command></term>
 719
 720                                 <listitem><para>Checks whether any of
 721                                 the specified unit files is enabled
 722                                 (as with
 723                                 <command>enable</command>). Returns an
 724                                 exit code of 0 if at least one is
 725                                 enabled, non-zero otherwise. Prints
 726                                 the current enable status. To suppress
 727                                 this output use
 728                                 <option>--quiet</option>.</para></listitem>
 729                         </varlistentry>
 730
 731                         <varlistentry>
 732                                 <term><command>reenable [NAME...]</command></term>
 733
 734                                 <listitem><para>Reenable one or more
 735                                 unit files, as specified on the
 736                                 command line. This is a combination of
 737                                 <command>disable</command> and
 738                                 <command>enable</command> and is
 739                                 useful to reset the symlinks a unit is
 740                                 enabled with to the defaults
 741                                 configured in the
 742                                 <literal>[Install]</literal> section
 743                                 of the unit file.</para>
 744                                 </listitem>
 745                         </varlistentry>
 746
 747                         <varlistentry>
 748                                 <term><command>preset [NAME...]</command></term>
 749
 750                                 <listitem><para>Reset one or more unit
 751                                 files, as specified on the command
 752                                 line, to the defaults configured in a
 753                                 preset file. This has the same effect
 754                                 as <command>disable</command> or
 755                                 <command>enable</command>, depending
 756                                 how the unit is listed in the preset
 757                                 files.</para>
 758                                 </listitem>
 759                         </varlistentry>
 760
 761                         <varlistentry>
 762                                 <term><command>mask [NAME...]</command></term>
 763
 764                                 <listitem><para>Mask one or more unit
 765                                 files, as specified on the command
 766                                 line. This will link these units to
 767                                 <filename>/dev/null</filename>, making
 768                                 it impossible to start them. This is a stronger version
 769                                 of <command>disable</command>, since
 770                                 it prohibits all kinds of activation
 771                                 of the unit, including manual
 772                                 activation. Use this option with
 773                                 care.</para>
 774                                 </listitem>
 775                         </varlistentry>
 776
 777                         <varlistentry>
 778                                 <term><command>unmask [NAME...]</command></term>
 779
 780                                 <listitem><para>Unmask one or more
 781                                 unit files, as specified on the
 782                                 command line. This will undo the
 783                                 effect of
 784                                 <command>mask</command>.</para>
 785                                 </listitem>
 786                         </varlistentry>
 787
 788                         <varlistentry>
 789                                 <term><command>link [NAME...]</command></term>
 790
 791                                 <listitem><para>Link a unit file that
 792                                 is not in the unit file search paths
 793                                 into the unit file search path. This
 794                                 requires an absolute path to a unit
 795                                 file. The effect of this can be undone
 796                                 with <command>disable</command>. The
 797                                 effect of this command is that a unit
 798                                 file is available for
 799                                 <command>start</command> and other
 800                                 commands although it isn't installed
 801                                 directly in the unit search
 802                                 path.</para>
 803                                 </listitem>
 804                         </varlistentry>
 805
 806                         <varlistentry>
 807                                 <term><command>load [NAME...]</command></term>
 808
 809                                 <listitem><para>Load one or more units
 810                                 specified on the command line. This
 811                                 will simply load their configuration
 812                                 from disk, but not start them. To
 813                                 start them you need to use the
 814                                 <command>start</command> command which
 815                                 will implicitly load a unit that has
 816                                 not been loaded yet. Note that systemd
 817                                 garbage collects loaded units that are
 818                                 not active or referenced by an active
 819                                 unit. This means that units loaded
 820                                 this way will usually not stay loaded
 821                                 for long. Also note that this command
 822                                 cannot be used to reload unit
 823                                 configuration. Use the
 824                                 <command>daemon-reload</command>
 825                                 command for that. All in all, this
 826                                 command is of little use except for
 827                                 debugging.</para>
 828                                 <para>This command should not be
 829                                 confused with the
 830                                 <command>daemon-reload</command> or
 831                                 <command>reload</command>
 832                                 commands.</para></listitem>
 833                         </varlistentry>
 834                         <varlistentry>
 835                                 <term><command>list-jobs</command></term>
 836
 837                                 <listitem><para>List jobs that are in progress.</para></listitem>
 838                         </varlistentry>
 839                         <varlistentry>
 840                                 <term><command>cancel [JOB...]</command></term>
 841
 842                                 <listitem><para>Cancel one or more
 843                                 jobs specified on the command line by
 844                                 their numeric job
 845                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 846                         </varlistentry>
 847                         <varlistentry>
 848                                 <term><command>dump</command></term>
 849
 850                                 <listitem><para>Dump server
 851                                 status. This will output a (usually
 852                                 very long) human readable manager
 853                                 status dump. Its format is subject to
 854                                 change without notice and should not
 855                                 be parsed by
 856                                 applications.</para></listitem>
 857                         </varlistentry>
 858                         <varlistentry>
 859                                 <term><command>dot</command></term>
 860
 861                                 <listitem><para>Generate textual
 862                                 dependency graph description in dot
 863                                 format for further processing with the
 864                                 GraphViz
 865                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 866                                 tool. Use a command line like
 867                                 <command>systemctl dot | dot -Tsvg >
 868                                 systemd.svg</command> to generate a
 869                                 graphical dependency tree. Unless
 870                                 <option>--order</option> or
 871                                 <option>--require</option> is passed
 872                                 the generated graph will show both
 873                                 ordering and requirement
 874                                 dependencies.</para></listitem>
 875                         </varlistentry>
 876                         <varlistentry>
 877                                 <term><command>snapshot [NAME]</command></term>
 878
 879                                 <listitem><para>Create a snapshot. If
 880                                 a snapshot name is specified, the new
 881                                 snapshot will be named after it. If
 882                                 none is specified an automatic
 883                                 snapshot name is generated. In either
 884                                 case, the snapshot name used is
 885                                 printed to STDOUT, unless
 886                                 <option>--quiet</option> is
 887                                 specified.</para>
 888
 889                                 <para>A snapshot refers to a saved
 890                                 state of the systemd manager. It is
 891                                 implemented itself as a unit that is
 892                                 generated dynamically with this
 893                                 command and has dependencies on all
 894                                 units active at the time. At a later
 895                                 time the user may return to this state
 896                                 by using the
 897                                 <command>isolate</command> command on
 898                                 the snapshot unit.</para></listitem>
 899
 900                                 <para>Snapshots are only useful for
 901                                 saving and restoring which units are
 902                                 running or are stopped, they do not
 903                                 save/restore any other
 904                                 state. Snapshots are dynamic and lost
 905                                 on reboot.</para>
 906                         </varlistentry>
 907                         <varlistentry>
 908                                 <term><command>delete [NAME...]</command></term>
 909
 910                                 <listitem><para>Remove a snapshot
 911                                 previously created with
 912                                 <command>snapshot</command>.</para></listitem>
 913                         </varlistentry>
 914                         <varlistentry>
 915                                 <term><command>daemon-reload</command></term>
 916
 917                                 <listitem><para>Reload systemd manager
 918                                 configuration. This will reload all
 919                                 unit files and recreate the entire
 920                                 dependency tree. While the daemon is
 921                                 reloaded, all sockets systemd listens
 922                                 on on behalf of user configuration will
 923                                 stay accessible.</para> <para>This
 924                                 command should not be confused with
 925                                 the <command>load</command> or
 926                                 <command>reload</command>
 927                                 commands.</para></listitem>
 928                         </varlistentry>
 929                         <varlistentry>
 930                                 <term><command>daemon-reexec</command></term>
 931
 932                                 <listitem><para>Reexecute the systemd
 933                                 manager. This will serialize the
 934                                 manager state, reexecute the process
 935                                 and deserialize the state again. This
 936                                 command is of little use except for
 937                                 debugging and package
 938                                 upgrades. Sometimes it might be
 939                                 helpful as a heavy-weight
 940                                 <command>daemon-reload</command>. While
 941                                 the daemon is reexecuted all sockets
 942                                 systemd listens on on behalf of user
 943                                 configuration will stay
 944                                 accessible.</para></listitem>
 945                         </varlistentry>
 946                         <varlistentry>
 947                                 <term><command>show-environment</command></term>
 948
 949                                 <listitem><para>Dump the systemd
 950                                 manager environment block. The
 951                                 environment block will be dumped in
 952                                 straight-forward form suitable for
 953                                 sourcing into a shell script. This
 954                                 environment block will be passed to
 955                                 all processes the manager
 956                                 spawns.</para></listitem>
 957                         </varlistentry>
 958                         <varlistentry>
 959                                 <term><command>set-environment [NAME=VALUE...]</command></term>
 960
 961                                 <listitem><para>Set one or more
 962                                 systemd manager environment variables,
 963                                 as specified on the command
 964                                 line.</para></listitem>
 965                         </varlistentry>
 966                         <varlistentry>
 967                                 <term><command>unset-environment [NAME...]</command></term>
 968
 969                                 <listitem><para>Unset one or more
 970                                 systemd manager environment
 971                                 variables. If only a variable name is
 972                                 specified it will be removed
 973                                 regardless of its value. If a variable
 974                                 and a value are specified the variable
 975                                 is only removed if it has the
 976                                 specified value.</para></listitem>
 977                         </varlistentry>
 978                         <varlistentry>
 979                                 <term><command>default</command></term>
 980
 981                                 <listitem><para>Enter default
 982                                 mode. This is mostly equivalent to
 983                                 <command>start
 984                                 default.target</command>.</para></listitem>
 985                         </varlistentry>
 986                         <varlistentry>
 987                                 <term><command>rescue</command></term>
 988
 989                                 <listitem><para>Enter rescue
 990                                 mode. This is mostly equivalent to
 991                                 <command>isolate
 992                                 rescue.target</command> but also
 993                                 prints a wall message to all
 994                                 users.</para></listitem>
 995                         </varlistentry>
 996                         <varlistentry>
 997                                 <term><command>emergency</command></term>
 998
 999                                 <listitem><para>Enter emergency
1000                                 mode. This is mostly equivalent to
1001                                 <command>isolate
1002                                 emergency.target</command> but also
1003                                 prints a wall message to all
1004                                 users.</para></listitem>
1005                         </varlistentry>
1006                         <varlistentry>
1007                                 <term><command>halt</command></term>
1008
1009                                 <listitem><para>Shut down and halt the
1010                                 system. This is mostly equivalent to
1011                                 <command>start halt.target</command>
1012                                 but also prints a wall message to all
1013                                 users.  If
1014                                 combined with <option>--force</option>
1015                                 shutdown of all running services is
1016                                 skipped, however all processes are killed
1017                                 and all file systems are unmounted or
1018                                 mounted read-only, immediately
1019                                 followed by the
1020                                 system halt.</para></listitem>
1021                         </varlistentry>
1022                         <varlistentry>
1023                                 <term><command>poweroff</command></term>
1024
1025                                 <listitem><para>Shut down and
1026                                 power-off the system. This is mostly
1027                                 equivalent to <command>start
1028                                 poweroff.target</command> but also
1029                                 prints a wall message to all
1030                                 users. If
1031                                 combined with <option>--force</option>
1032                                 shutdown of all running services is
1033                                 skipped, however all processes are killed
1034                                 and all file systems are unmounted or
1035                                 mounted read-only, immediately
1036                                 followed by the
1037                                 powering off.</para></listitem>
1038                         </varlistentry>
1039                         <varlistentry>
1040                                 <term><command>reboot</command></term>
1041
1042                                 <listitem><para>Shut down and
1043                                 reboot the system. This is mostly
1044                                 equivalent to <command>start
1045                                 reboot.target</command> but also
1046                                 prints a wall message to all
1047                                 users. If
1048                                 combined with <option>--force</option>
1049                                 shutdown of all running services is
1050                                 skipped, however all processes are killed
1051                                 and all file systems are unmounted or
1052                                 mounted read-only, immediately
1053                                 followed by the
1054                                 reboot.</para></listitem>
1055                         </varlistentry>
1056                         <varlistentry>
1057                                 <term><command>kexec</command></term>
1058
1059                                 <listitem><para>Shut down and reboot
1060                                 the system via kexec. This is mostly
1061                                 equivalent to <command>start
1062                                 kexec.target</command> but also prints
1063                                 a wall message to all users. If
1064                                 combined with <option>--force</option>
1065                                 shutdown of all running services is
1066                                 skipped, however all processes are killed
1067                                 and all file systems are unmounted or
1068                                 mounted read-only, immediately
1069                                 followed by the
1070                                 reboot.</para></listitem>
1071                         </varlistentry>
1072                         <varlistentry>
1073                                 <term><command>exit</command></term>
1074
1075                                 <listitem><para>Ask the systemd
1076                                 manager to quit. This is only
1077                                 supported for user service managers
1078                                 (i.e. in conjunction with the
1079                                 <option>--user</option> option) and
1080                                 will fail otherwise.</para></listitem>
1081                         </varlistentry>
1082                 </variablelist>
1083
1084         </refsect1>
1085
1086         <refsect1>
1087                 <title>Exit status</title>
1088
1089                 <para>On success 0 is returned, a non-zero failure
1090                 code otherwise.</para>
1091         </refsect1>
1092
1093         <refsect1>
1094                 <title>Environment</title>
1095
1096                 <variablelist>
1097                         <varlistentry>
1098                                 <term><varname>$SYSTEMD_PAGER</varname></term>
1099                                 <listitem><para>Pager to use when
1100                                 <option>--no-pager</option> is not given;
1101                                 overrides <varname>$PAGER</varname>.  Setting
1102                                 this to an empty string or the value
1103                                 <literal>cat</literal> is equivalent to passing
1104                                 <option>--no-pager</option>.</para></listitem>
1105                         </varlistentry>
1106                 </variablelist>
1107         </refsect1>
1108
1109         <refsect1>
1110                 <title>See Also</title>
1111                 <para>
1112                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1113                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1114                         <citerefentry><refentrytitle>systemd-loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1115                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1116                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1117                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1118                 </para>
1119         </refsect1>
1120
1121 </refentry>