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