man/systemctl.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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   6   This file is part of systemd.
   7
   8   Copyright 2010 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 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
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  18   Lesser General Public License for more details.
  19
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  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>The argument should
  91                                 be a unit type name such as
  92                                 <option>service</option> and
  93                                 <option>socket</option>,
  94                                 or a unit load state such as
  95                                 <option>loaded</option> and
  96                                 <option>masked</option>.
  97                                 </para>
  98
  99                                 <para>If the argument is a unit type,
 100                                 when listing units, limit display to
 101                                 certain unit types. If not specified
 102                                 units of all types will be shown.</para>
 103
 104                                 <para>If the argument is a unit load state,
 105                                 when listing units, limit display to
 106                                 certain unit types. If not specified
 107                                 units of in all load states will be
 108                                 shown.</para>
 109                                 </listitem>
 110                         </varlistentry>
 111
 112                         <varlistentry>
 113                                 <term><option>--property=</option></term>
 114                                 <term><option>-p</option></term>
 115
 116                                 <listitem><para>When showing
 117                                 unit/job/manager properties, limit
 118                                 display to certain properties as
 119                                 specified as argument. If not
 120                                 specified all set properties are
 121                                 shown. The argument should be a
 122                                 property name, such as
 123                                 <literal>MainPID</literal>. If
 124                                 specified more than once all
 125                                 properties with the specified names
 126                                 are shown.</para></listitem>
 127                         </varlistentry>
 128
 129                         <varlistentry>
 130                                 <term><option>--all</option></term>
 131                                 <term><option>-a</option></term>
 132
 133                                 <listitem><para>When listing units,
 134                                 show all units, regardless of their
 135                                 state, including inactive units. When
 136                                 showing unit/job/manager properties,
 137                                 show all properties regardless whether
 138                                 they are set or not.</para></listitem>
 139                         </varlistentry>
 140
 141                         <varlistentry>
 142                                 <term><option>--failed</option></term>
 143
 144                                 <listitem><para>When listing units,
 145                                 show only failed units. Do not confuse
 146                                 with
 147                                 <option>--fail</option>.</para></listitem>
 148                         </varlistentry>
 149
 150                         <varlistentry>
 151                                 <term><option>--full</option></term>
 152
 153                                 <listitem><para>Do not ellipsize unit
 154                                 names and truncate unit descriptions
 155                                 in the output of
 156                                 <command>list-units</command> and
 157                                 <command>list-jobs</command>.</para></listitem>
 158                         </varlistentry>
 159
 160                         <varlistentry>
 161                                 <term><option>--fail</option></term>
 162
 163                                 <listitem><para>If the requested
 164                                 operation conflicts with a pending
 165                                 unfinished job, fail the command. If
 166                                 this is not specified the requested
 167                                 operation will replace the pending job,
 168                                 if necessary. Do not confuse
 169                                 with
 170                                 <option>--failed</option>.</para></listitem>
 171                         </varlistentry>
 172
 173                         <varlistentry>
 174                                 <term><option>--ignore-dependencies</option></term>
 175
 176                                 <listitem><para>When enqueuing a new
 177                                 job ignore all its dependencies and
 178                                 execute it immediately. If passed no
 179                                 required units of the unit passed will
 180                                 be pulled in, and no ordering
 181                                 dependencies will be honoured. This is
 182                                 mostly a debugging and rescue tool for
 183                                 the administrator and should not be
 184                                 used by
 185                                 applications.</para></listitem>
 186                         </varlistentry>
 187
 188                         <varlistentry>
 189                                 <term><option>--quiet</option></term>
 190                                 <term><option>-q</option></term>
 191
 192                                 <listitem><para>Suppress output to
 193                                 STDOUT in
 194                                 <command>snapshot</command>,
 195                                 <command>is-active</command>,
 196                                 <command>enable</command> and
 197                                 <command>disable</command>.</para></listitem>
 198                         </varlistentry>
 199
 200                         <varlistentry>
 201                                 <term><option>--no-block</option></term>
 202
 203                                 <listitem><para>Do not synchronously wait for
 204                                 the requested operation to finish. If this is
 205                                 not specified the job will be verified,
 206                                 enqueued and <command>systemctl</command> will
 207                                 wait until it is completed. By passing this
 208                                 argument it is only verified and
 209                                 enqueued.</para></listitem>
 210                         </varlistentry>
 211
 212                         <varlistentry>
 213                                 <term><option>--no-legend</option></term>
 214
 215                                 <listitem><para>Do not print a legend, i.e.
 216                                 the column headers and the footer with hints.
 217                                 </para></listitem>
 218                         </varlistentry>
 219
 220                         <varlistentry>
 221                                 <term><option>--no-pager</option></term>
 222
 223                                 <listitem><para>Do not pipe output into a
 224                                 pager.</para></listitem>
 225                         </varlistentry>
 226
 227                         <varlistentry>
 228                                 <term><option>--system</option></term>
 229
 230                                 <listitem><para>Talk to the systemd
 231                                 system manager. (Default)</para></listitem>
 232                         </varlistentry>
 233
 234                         <varlistentry>
 235                                 <term><option>--user</option></term>
 236
 237                                 <listitem><para>Talk to the systemd
 238                                 manager of the calling user.</para></listitem>
 239                         </varlistentry>
 240
 241                         <varlistentry>
 242                                 <term><option>--order</option></term>
 243                                 <term><option>--require</option></term>
 244
 245                                 <listitem><para>When used in
 246                                 conjunction with the
 247                                 <command>dot</command> command (see
 248                                 below), selects which dependencies are
 249                                 shown in the dependency graph. If
 250                                 <option>--order</option> is passed
 251                                 only dependencies of type
 252                                 <varname>After=</varname> or
 253                                 <varname>Before=</varname> are
 254                                 shown. If <option>--require</option>
 255                                 is passed only dependencies of type
 256                                 <varname>Requires=</varname>,
 257                                 <varname>RequiresOverridable=</varname>,
 258                                 <varname>Requisite=</varname>,
 259                                 <varname>RequisiteOverridable=</varname>,
 260                                 <varname>Wants=</varname> and
 261                                 <varname>Conflicts=</varname> are
 262                                 shown. If neither is passed, shows
 263                                 dependencies of all these
 264                                 types.</para></listitem>
 265                         </varlistentry>
 266
 267                         <varlistentry>
 268                                 <term><option>--no-wall</option></term>
 269
 270                                 <listitem><para>Don't send wall
 271                                 message before
 272                                 halt, power-off, reboot.</para></listitem>
 273                         </varlistentry>
 274
 275                         <varlistentry>
 276                                 <term><option>--global</option></term>
 277
 278                                 <listitem><para>When used with
 279                                 <command>enable</command> and
 280                                 <command>disable</command>, operate on the
 281                                 global user configuration
 282                                 directory, thus enabling or disabling
 283                                 a unit file globally for all future
 284                                 logins of all users.</para></listitem>
 285                         </varlistentry>
 286
 287                         <varlistentry>
 288                                 <term><option>--no-reload</option></term>
 289
 290                                 <listitem><para>When used with
 291                                 <command>enable</command> and
 292                                 <command>disable</command>, do not
 293                                 implicitly reload daemon configuration
 294                                 after executing the
 295                                 changes.</para></listitem>
 296                         </varlistentry>
 297
 298                         <varlistentry>
 299                                 <term><option>--no-ask-password</option></term>
 300
 301                                 <listitem><para>When used with
 302                                 <command>start</command> and related
 303                                 commands, disables asking for
 304                                 passwords. Background services may
 305                                 require input of a password or
 306                                 passphrase string, for example to
 307                                 unlock system hard disks or
 308                                 cryptographic certificates. Unless
 309                                 this option is specified and the
 310                                 command is invoked from a terminal
 311                                 <command>systemctl</command> will
 312                                 query the user on the terminal for the
 313                                 necessary secrets. Use this option to
 314                                 switch this behavior off. In this case
 315                                 the password must be supplied by some
 316                                 other means (for example graphical
 317                                 password agents) or the service might
 318                                 fail. This also disables querying the
 319                                 user for authentication for privileged
 320                                 operations.</para></listitem>
 321                         </varlistentry>
 322
 323                         <varlistentry>
 324                                 <term><option>--kill-who=</option></term>
 325
 326                                 <listitem><para>When used with
 327                                 <command>kill</command>, choose which
 328                                 processes to kill. Must be one of
 329                                 <option>main</option>,
 330                                 <option>control</option> or
 331                                 <option>all</option> to select whether
 332                                 to kill only the main process of the
 333                                 unit, the control process or all
 334                                 processes of the unit. If omitted
 335                                 defaults to
 336                                 <option>all</option>.</para></listitem>
 337                         </varlistentry>
 338
 339                         <varlistentry>
 340                                 <term><option>--signal=</option></term>
 341                                 <term><option>-s</option></term>
 342
 343                                 <listitem><para>When used with
 344                                 <command>kill</command>, choose which
 345                                 signal to send to selected
 346                                 processes. Must be one of the well
 347                                 known signal specifiers such as
 348                                 SIGTERM, SIGINT or SIGSTOP. If
 349                                 omitted defaults to
 350                                 <option>SIGTERM</option>.</para></listitem>
 351                         </varlistentry>
 352
 353                         <varlistentry>
 354                                 <term><option>--force</option></term>
 355                                 <term><option>-f</option></term>
 356
 357                                 <listitem><para>When used with
 358                                 <command>enable</command>, overwrite any
 359                                 existing conflicting
 360                                 symlinks.</para></listitem>
 361
 362                                 <listitem><para>When used with
 363                                 <command>halt</command>,
 364                                 <command>poweroff</command>,
 365                                 <command>reboot</command> or
 366                                 <command>kexec</command> execute the
 367                                 selected operation without shutting
 368                                 down all units. However, all processes
 369                                 will be killed forcibly and all file
 370                                 systems are unmounted or remounted
 371                                 read-only. This is hence a drastic but
 372                                 relatively safe option to request an
 373                                 immediate reboot. If
 374                                 <option>--force</option> is specified
 375                                 twice for these operations, they will
 376                                 be executed immediately without
 377                                 terminating any processes or umounting
 378                                 any file systems. Warning: specifying
 379                                 <option>--force</option> twice with
 380                                 any of these operations might result
 381                                 in data loss.</para></listitem>
 382                         </varlistentry>
 383
 384                         <varlistentry>
 385                                 <term><option>--root=</option></term>
 386
 387                                 <listitem><para>When used with
 388                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and
 389                                 related commands), use alternative
 390                                 root path when looking for unit
 391                                 files.</para></listitem>
 392                         </varlistentry>
 393
 394                         <varlistentry>
 395                                 <term><option>--runtime</option></term>
 396
 397                                 <listitem><para>When used with
 398                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and related commands), make
 399                                 changes only temporarily, so that they
 400                                 are dropped on the next reboot. This
 401                                 will have the effect that changes are
 402                                 not made in subdirectories of
 403                                 <filename>/etc</filename> but in
 404                                 <filename>/run</filename>, with
 405                                 identical immediate effects, however,
 406                                 since the latter is lost on reboot,
 407                                 the changes are lost
 408                                 too.</para></listitem>
 409                         </varlistentry>
 410
 411                         <varlistentry>
 412                                 <term><option>-H</option></term>
 413                                 <term><option>--host</option></term>
 414
 415                                 <listitem><para>Execute operation
 416                                 remotely. Specify a hostname, or
 417                                 username and hostname separated by @,
 418                                 to connect to. This will use SSH to
 419                                 talk to the remote systemd
 420                                 instance.</para></listitem>
 421                         </varlistentry>
 422
 423                         <varlistentry>
 424                                 <term><option>-P</option></term>
 425                                 <term><option>--privileged</option></term>
 426
 427                                 <listitem><para>Acquire privileges via
 428                                 PolicyKit before executing the
 429                                 operation.</para></listitem>
 430                         </varlistentry>
 431
 432                         <varlistentry>
 433                                 <term><option>--lines=</option></term>
 434                                 <term><option>-n</option></term>
 435
 436                                 <listitem><para>When used with
 437                                 <command>status</command> controls the
 438                                 number of journal lines to show,
 439                                 counting from the most recent
 440                                 ones. Takes a positive integer
 441                                 argument. Defaults to
 442                                 10.</para></listitem>
 443                         </varlistentry>
 444
 445                         <varlistentry>
 446                                 <term><option>--follow</option></term>
 447                                 <term><option>-f</option></term>
 448
 449                                 <listitem><para>When used with
 450                                 <command>status</command> continuously
 451                                 prints new journal entries as they are
 452                                 appended to the
 453                                 journal.</para></listitem>
 454                         </varlistentry>
 455
 456                         <varlistentry>
 457                                 <term><option>--output=</option></term>
 458                                 <term><option>-o</option></term>
 459
 460                                 <listitem><para>When used with
 461                                 <command>status</command> controls the
 462                                 formatting of the journal entries that
 463                                 are shown. For the available choices
 464                                 see
 465                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Defaults
 466                                 to
 467                                 <literal>short</literal>.</para></listitem>
 468                         </varlistentry>
 469
 470                 </variablelist>
 471
 472                 <para>The following commands are understood:</para>
 473
 474                 <variablelist>
 475                         <varlistentry>
 476                                 <term><command>list-units</command></term>
 477
 478                                 <listitem><para>List known units.</para></listitem>
 479                         </varlistentry>
 480                         <varlistentry>
 481                                 <term><command>start [NAME...]</command></term>
 482
 483                                 <listitem><para>Start (activate) one
 484                                 or more units specified on the command
 485                                 line.</para></listitem>
 486                         </varlistentry>
 487                         <varlistentry>
 488                                 <term><command>stop [NAME...]</command></term>
 489
 490                                 <listitem><para>Stop (deactivate) one
 491                                 or more units specified on the command
 492                                 line.</para></listitem>
 493                         </varlistentry>
 494                         <varlistentry>
 495                                 <term><command>reload [NAME...]</command></term>
 496
 497                                 <listitem><para>Asks all units listed
 498                                 on the command line to reload their
 499                                 configuration. Note that this will
 500                                 reload the service-specific
 501                                 configuration, not the unit
 502                                 configuration file of systemd. If you
 503                                 want systemd to reload the
 504                                 configuration file of a unit use the
 505                                 <command>daemon-reload</command>
 506                                 command. In other words: for the
 507                                 example case of Apache, this will
 508                                 reload Apache's
 509                                 <filename>httpd.conf</filename> in the
 510                                 web server, not the
 511                                 <filename>apache.service</filename>
 512                                 systemd unit file. </para>
 513
 514                                 <para>This command should not be
 515                                 confused with the
 516                                 <command>daemon-reload</command> or
 517                                 <command>load</command>
 518                                 commands.</para></listitem>
 519
 520                         </varlistentry>
 521                         <varlistentry>
 522                                 <term><command>restart [NAME...]</command></term>
 523
 524                                 <listitem><para>Restart one or more
 525                                 units specified on the command
 526                                 line. If the units are not running yet
 527                                 they will be
 528                                 started.</para></listitem>
 529                         </varlistentry>
 530                         <varlistentry>
 531                                 <term><command>try-restart [NAME...]</command></term>
 532
 533                                 <listitem><para>Restart one or more
 534                                 units specified on the command
 535                                 line if the units are running. Do
 536                                 nothing if units are not running.
 537                                 Note that for compatibility
 538                                 with Red Hat init scripts
 539                                 <command>condrestart</command> is
 540                                 equivalent to this command.</para></listitem>
 541                         </varlistentry>
 542                         <varlistentry>
 543                                 <term><command>reload-or-restart [NAME...]</command></term>
 544
 545                                 <listitem><para>Reload one or more
 546                                 units if they support it. If not,
 547                                 restart them instead. If the units
 548                                 are not running yet they will be
 549                                 started.</para></listitem>
 550                         </varlistentry>
 551                         <varlistentry>
 552                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 553
 554                                 <listitem><para>Reload one or more
 555                                 units if they support it. If not,
 556                                 restart them instead. Do nothing if
 557                                 the units are not running. Note that
 558                                 for compatibility with SysV init
 559                                 scripts
 560                                 <command>force-reload</command> is
 561                                 equivalent to this
 562                                 command.</para></listitem>
 563                         </varlistentry>
 564                         <varlistentry>
 565                                 <term><command>isolate [NAME]</command></term>
 566
 567                                 <listitem><para>Start the unit
 568                                 specified on the command line and its
 569                                 dependencies and stop all others.</para>
 570
 571                                 <para>This is similar to changing the
 572                                 runlevel in a traditional init system. The
 573                                 <command>isolate</command> command will
 574                                 immediately stop processes that are not
 575                                 enabled in the new unit, possibly including
 576                                 the graphical environment or terminal you
 577                                 are currently using.</para>
 578
 579                                 <para>Note that this works only on units
 580                                 where <option>AllowIsolate=</option> is
 581                                 enabled. See
 582                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 583                                 for details.</para></listitem>
 584                         </varlistentry>
 585                         <varlistentry>
 586                                 <term><command>kill [NAME...]</command></term>
 587
 588                                 <listitem><para>Send a signal to one
 589                                 or more processes of the unit. Use
 590                                 <option>--kill-who=</option> to select
 591                                 which process to kill. Use
 592                                 <option>--kill-mode=</option> to
 593                                 select the kill mode and
 594                                 <option>--signal=</option> to select
 595                                 the signal to send.</para></listitem>
 596                         </varlistentry>
 597                         <varlistentry>
 598                                 <term><command>is-active [NAME...]</command></term>
 599
 600                                 <listitem><para>Check whether any of
 601                                 the specified units are active
 602                                 (i.e. running). Returns an exit code
 603                                 0 if at least one is active, non-zero
 604                                 otherwise. Unless
 605                                 <option>--quiet</option> is specified
 606                                 this will also print the current unit
 607                                 state to STDOUT.</para></listitem>
 608                         </varlistentry>
 609                         <varlistentry>
 610                                 <term><command>status [NAME...|PID...]</command></term>
 611
 612                                 <listitem><para>Show terse runtime
 613                                 status information about one or more
 614                                 units, followed by its most recent log
 615                                 data from the journal. This function
 616                                 is intended to generate human-readable
 617                                 output. If you are looking for
 618                                 computer-parsable output, use
 619                                 <command>show</command> instead. If a
 620                                 PID is passed information about the
 621                                 unit the process of the PID belongs to
 622                                 is shown.</para></listitem>
 623                         </varlistentry>
 624                         <varlistentry>
 625                                 <term><command>show [NAME...|JOB...]</command></term>
 626
 627                                 <listitem><para>Show properties of one
 628                                 or more units, jobs or the manager
 629                                 itself. If no argument is specified
 630                                 properties of the manager will be
 631                                 shown. If a unit name is specified
 632                                 properties of the unit is shown, and
 633                                 if a job id is specified properties of
 634                                 the job is shown. By default, empty
 635                                 properties are suppressed. Use
 636                                 <option>--all</option> to show those
 637                                 too. To select specific properties to
 638                                 show use
 639                                 <option>--property=</option>. This
 640                                 command is intended to be used
 641                                 whenever computer-parsable output is
 642                                 required. Use
 643                                 <command>status</command> if you are
 644                                 looking for formatted human-readable
 645                                 output.</para></listitem>
 646                         </varlistentry>
 647                         <varlistentry>
 648                                 <term><command>help [NAME...|PID...]</command></term>
 649
 650                                 <listitem><para>Show manual pages for
 651                                 one or more units, if available. If a
 652                                 PID is passed the manual pages for the
 653                                 unit the process of the PID belongs to
 654                                 is shown.</para></listitem>
 655                         </varlistentry>
 656                         <varlistentry>
 657                                 <term><command>reset-failed [NAME...]</command></term>
 658
 659                                 <listitem><para>Reset the
 660                                 '<literal>failed</literal>' state of the
 661                                 specified units, or if no unit name is
 662                                 passed of all units. When a unit fails
 663                                 in some way (i.e. process exiting with
 664                                 non-zero error code, terminating
 665                                 abnormally or timing out) it will
 666                                 automatically enter the
 667                                 '<literal>failed</literal>' state and
 668                                 its exit code and status is recorded
 669                                 for introspection by the administrator
 670                                 until the service is restarted or
 671                                 reset with this
 672                                 command.</para></listitem>
 673                         </varlistentry>
 674
 675                         <varlistentry>
 676                                 <term><command>list-unit-files</command></term>
 677
 678                                 <listitem><para>List installed unit files.
 679                                 </para></listitem>
 680                         </varlistentry>
 681
 682                         <varlistentry>
 683                                 <term><command>enable [NAME...]</command></term>
 684
 685                                 <listitem><para>Enable one or
 686                                 more unit files or unit file
 687                                 instances, as specified on the
 688                                 command line. This will create a
 689                                 number of symlinks as encoded in
 690                                 the <literal>[Install]</literal>
 691                                 sections of the unit files. After
 692                                 the symlinks have been created the
 693                                 systemd configuration is reloaded
 694                                 (in a way that is equivalent to
 695                                 <command>daemon-reload</command>)
 696                                 to ensure the changes are taken into
 697                                 account immediately. Note that this
 698                                 does not have the effect that any of
 699                                 the units enabled are also started at
 700                                 the same time.  If this is desired
 701                                 a separate <command>start</command>
 702                                 command must be invoked for the unit.
 703                                 Also note that in case of instance
 704                                 enablement, symlinks named same as
 705                                 instances are created in install
 706                                 location, however they all point to
 707                                 the same template unit file.</para>
 708
 709                                 <para>This command will
 710                                 print the actions executed. This
 711                                 output may be suppressed by passing
 712                                 <option>--quiet</option>.</para>
 713
 714                                 <para>Note that this operation creates
 715                                 only the suggested symlinks for the
 716                                 units. While this command is the
 717                                 recommended way to manipulate the unit
 718                                 configuration directory, the
 719                                 administrator is free to make
 720                                 additional changes manually, by
 721                                 placing or removing symlinks in the
 722                                 directory. This is particularly useful
 723                                 to create configurations that deviate
 724                                 from the suggested default
 725                                 installation. In this case the
 726                                 administrator must make sure to invoke
 727                                 <command>daemon-reload</command>
 728                                 manually as necessary, to ensure his
 729                                 changes are taken into account.</para>
 730
 731                                 <para>Enabling units should not be
 732                                 confused with starting (activating)
 733                                 units, as done by the
 734                                 <command>start</command>
 735                                 command. Enabling and starting units
 736                                 is orthogonal: units may be enabled
 737                                 without being started and started
 738                                 without being enabled. Enabling simply
 739                                 hooks the unit into various suggested
 740                                 places (for example, so that the unit
 741                                 is automatically started on boot or
 742                                 when a particular kind of hardware is
 743                                 plugged in). Starting actually spawns
 744                                 the daemon process (in case of service
 745                                 units), or binds the socket (in case
 746                                 of socket units), and so
 747                                 on.</para>
 748
 749                                 <para>Depending on whether
 750                                 <option>--system</option>,
 751                                 <option>--user</option> or
 752                                 <option>--global</option> is specified
 753                                 this enables the unit for the system,
 754                                 for the calling user only
 755                                 or for all future logins of all
 756                                 users. Note that in the latter case no
 757                                 systemd daemon configuration is
 758                                 reloaded.</para>
 759                                 </listitem>
 760                         </varlistentry>
 761
 762                         <varlistentry>
 763                                 <term><command>disable [NAME...]</command></term>
 764
 765                                 <listitem><para>Disables one or more
 766                                 units. This removes all symlinks to
 767                                 the specified unit files from the unit
 768                                 configuration directory, and hence
 769                                 undoes the changes made by
 770                                 <command>enable</command>. Note
 771                                 however that this removes
 772                                 all symlinks to the unit files
 773                                 (i.e. including manual additions), not
 774                                 just those actually created by
 775                                 <command>enable</command>. This call
 776                                 implicitly reloads the systemd daemon
 777                                 configuration after completing the
 778                                 disabling of the units. Note that this
 779                                 command does not implicitly stop the
 780                                 units that is being disabled. If this
 781                                 is desired an additional
 782                                 <command>stop</command> command should
 783                                 be executed afterwards.</para>
 784
 785                                 <para>This command will print the
 786                                 actions executed. This output may be
 787                                 suppressed by passing
 788                                 <option>--quiet</option>.</para>
 789                                 </listitem>
 790
 791                                 <para>This command honors
 792                                 <option>--system</option>,
 793                                 <option>--user</option>,
 794                                 <option>--global</option> in a similar
 795                                 way as
 796                                 <command>enable</command>.</para>
 797                         </varlistentry>
 798
 799                         <varlistentry>
 800                                 <term><command>is-enabled [NAME...]</command></term>
 801
 802                                 <listitem><para>Checks whether any of
 803                                 the specified unit files is enabled
 804                                 (as with
 805                                 <command>enable</command>). Returns an
 806                                 exit code of 0 if at least one is
 807                                 enabled, non-zero otherwise. Prints
 808                                 the current enable status. To suppress
 809                                 this output use
 810                                 <option>--quiet</option>.</para></listitem>
 811                         </varlistentry>
 812
 813                         <varlistentry>
 814                                 <term><command>reenable [NAME...]</command></term>
 815
 816                                 <listitem><para>Reenable one or more
 817                                 unit files, as specified on the
 818                                 command line. This is a combination of
 819                                 <command>disable</command> and
 820                                 <command>enable</command> and is
 821                                 useful to reset the symlinks a unit is
 822                                 enabled with to the defaults
 823                                 configured in the
 824                                 <literal>[Install]</literal> section
 825                                 of the unit file.</para>
 826                                 </listitem>
 827                         </varlistentry>
 828
 829                         <varlistentry>
 830                                 <term><command>preset [NAME...]</command></term>
 831
 832                                 <listitem><para>Reset one or more unit
 833                                 files, as specified on the command
 834                                 line, to the defaults configured in
 835                                 the preset policy files. This has the
 836                                 same effect as
 837                                 <command>disable</command> or
 838                                 <command>enable</command>, depending
 839                                 how the unit is listed in the preset
 840                                 files. For more information on preset
 841                                 policy format see
 842                                 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 843                                 more information on the concept of
 844                                 presets please consult the <ulink
 845                                 url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
 846                                 document.</para>
 847                                 </listitem>
 848                         </varlistentry>
 849
 850                         <varlistentry>
 851                                 <term><command>mask [NAME...]</command></term>
 852
 853                                 <listitem><para>Mask one or more unit
 854                                 files, as specified on the command
 855                                 line. This will link these units to
 856                                 <filename>/dev/null</filename>, making
 857                                 it impossible to start them. This is a stronger version
 858                                 of <command>disable</command>, since
 859                                 it prohibits all kinds of activation
 860                                 of the unit, including manual
 861                                 activation. Use this option with
 862                                 care.</para>
 863                                 </listitem>
 864                         </varlistentry>
 865
 866                         <varlistentry>
 867                                 <term><command>unmask [NAME...]</command></term>
 868
 869                                 <listitem><para>Unmask one or more
 870                                 unit files, as specified on the
 871                                 command line. This will undo the
 872                                 effect of
 873                                 <command>mask</command>.</para>
 874                                 </listitem>
 875                         </varlistentry>
 876
 877                         <varlistentry>
 878                                 <term><command>link [NAME...]</command></term>
 879
 880                                 <listitem><para>Link a unit file that
 881                                 is not in the unit file search paths
 882                                 into the unit file search path. This
 883                                 requires an absolute path to a unit
 884                                 file. The effect of this can be undone
 885                                 with <command>disable</command>. The
 886                                 effect of this command is that a unit
 887                                 file is available for
 888                                 <command>start</command> and other
 889                                 commands although it isn't installed
 890                                 directly in the unit search
 891                                 path.</para>
 892                                 </listitem>
 893                         </varlistentry>
 894
 895                         <varlistentry>
 896                                 <term><command>load [NAME...]</command></term>
 897
 898                                 <listitem><para>Load one or more units
 899                                 specified on the command line. This
 900                                 will simply load their configuration
 901                                 from disk, but not start them. To
 902                                 start them you need to use the
 903                                 <command>start</command> command which
 904                                 will implicitly load a unit that has
 905                                 not been loaded yet. Note that systemd
 906                                 garbage collects loaded units that are
 907                                 not active or referenced by an active
 908                                 unit. This means that units loaded
 909                                 this way will usually not stay loaded
 910                                 for long. Also note that this command
 911                                 cannot be used to reload unit
 912                                 configuration. Use the
 913                                 <command>daemon-reload</command>
 914                                 command for that. All in all, this
 915                                 command is of little use except for
 916                                 debugging.</para>
 917                                 <para>This command should not be
 918                                 confused with the
 919                                 <command>daemon-reload</command> or
 920                                 <command>reload</command>
 921                                 commands.</para></listitem>
 922                         </varlistentry>
 923                         <varlistentry>
 924                                 <term><command>list-jobs</command></term>
 925
 926                                 <listitem><para>List jobs that are in progress.</para></listitem>
 927                         </varlistentry>
 928                         <varlistentry>
 929                                 <term><command>cancel [JOB...]</command></term>
 930
 931                                 <listitem><para>Cancel one or more
 932                                 jobs specified on the command line by
 933                                 their numeric job
 934                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 935                         </varlistentry>
 936                         <varlistentry>
 937                                 <term><command>dump</command></term>
 938
 939                                 <listitem><para>Dump server
 940                                 status. This will output a (usually
 941                                 very long) human readable manager
 942                                 status dump. Its format is subject to
 943                                 change without notice and should not
 944                                 be parsed by
 945                                 applications.</para></listitem>
 946                         </varlistentry>
 947                         <varlistentry>
 948                                 <term><command>dot</command></term>
 949
 950                                 <listitem><para>Generate textual
 951                                 dependency graph description in dot
 952                                 format for further processing with the
 953                                 GraphViz
 954                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 955                                 tool. Use a command line like
 956                                 <command>systemctl dot | dot -Tsvg >
 957                                 systemd.svg</command> to generate a
 958                                 graphical dependency tree. Unless
 959                                 <option>--order</option> or
 960                                 <option>--require</option> is passed
 961                                 the generated graph will show both
 962                                 ordering and requirement
 963                                 dependencies.</para></listitem>
 964                         </varlistentry>
 965                         <varlistentry>
 966                                 <term><command>snapshot [NAME]</command></term>
 967
 968                                 <listitem><para>Create a snapshot. If
 969                                 a snapshot name is specified, the new
 970                                 snapshot will be named after it. If
 971                                 none is specified an automatic
 972                                 snapshot name is generated. In either
 973                                 case, the snapshot name used is
 974                                 printed to STDOUT, unless
 975                                 <option>--quiet</option> is
 976                                 specified.</para>
 977
 978                                 <para>A snapshot refers to a saved
 979                                 state of the systemd manager. It is
 980                                 implemented itself as a unit that is
 981                                 generated dynamically with this
 982                                 command and has dependencies on all
 983                                 units active at the time. At a later
 984                                 time the user may return to this state
 985                                 by using the
 986                                 <command>isolate</command> command on
 987                                 the snapshot unit.</para></listitem>
 988
 989                                 <para>Snapshots are only useful for
 990                                 saving and restoring which units are
 991                                 running or are stopped, they do not
 992                                 save/restore any other
 993                                 state. Snapshots are dynamic and lost
 994                                 on reboot.</para>
 995                         </varlistentry>
 996                         <varlistentry>
 997                                 <term><command>delete [NAME...]</command></term>
 998
 999                                 <listitem><para>Remove a snapshot
1000                                 previously created with
1001                                 <command>snapshot</command>.</para></listitem>
1002                         </varlistentry>
1003                         <varlistentry>
1004                                 <term><command>daemon-reload</command></term>
1005
1006                                 <listitem><para>Reload systemd manager
1007                                 configuration. This will reload all
1008                                 unit files and recreate the entire
1009                                 dependency tree. While the daemon is
1010                                 reloaded, all sockets systemd listens
1011                                 on on behalf of user configuration will
1012                                 stay accessible.</para> <para>This
1013                                 command should not be confused with
1014                                 the <command>load</command> or
1015                                 <command>reload</command>
1016                                 commands.</para></listitem>
1017                         </varlistentry>
1018                         <varlistentry>
1019                                 <term><command>daemon-reexec</command></term>
1020
1021                                 <listitem><para>Reexecute the systemd
1022                                 manager. This will serialize the
1023                                 manager state, reexecute the process
1024                                 and deserialize the state again. This
1025                                 command is of little use except for
1026                                 debugging and package
1027                                 upgrades. Sometimes it might be
1028                                 helpful as a heavy-weight
1029                                 <command>daemon-reload</command>. While
1030                                 the daemon is reexecuted all sockets
1031                                 systemd listens on on behalf of user
1032                                 configuration will stay
1033                                 accessible.</para></listitem>
1034                         </varlistentry>
1035                         <varlistentry>
1036                                 <term><command>show-environment</command></term>
1037
1038                                 <listitem><para>Dump the systemd
1039                                 manager environment block. The
1040                                 environment block will be dumped in
1041                                 straight-forward form suitable for
1042                                 sourcing into a shell script. This
1043                                 environment block will be passed to
1044                                 all processes the manager
1045                                 spawns.</para></listitem>
1046                         </varlistentry>
1047                         <varlistentry>
1048                                 <term><command>set-environment [NAME=VALUE...]</command></term>
1049
1050                                 <listitem><para>Set one or more
1051                                 systemd manager environment variables,
1052                                 as specified on the command
1053                                 line.</para></listitem>
1054                         </varlistentry>
1055                         <varlistentry>
1056                                 <term><command>unset-environment [NAME...]</command></term>
1057
1058                                 <listitem><para>Unset one or more
1059                                 systemd manager environment
1060                                 variables. If only a variable name is
1061                                 specified it will be removed
1062                                 regardless of its value. If a variable
1063                                 and a value are specified the variable
1064                                 is only removed if it has the
1065                                 specified value.</para></listitem>
1066                         </varlistentry>
1067                         <varlistentry>
1068                                 <term><command>default</command></term>
1069
1070                                 <listitem><para>Enter default
1071                                 mode. This is mostly equivalent to
1072                                 <command>start
1073                                 default.target</command>.</para></listitem>
1074                         </varlistentry>
1075                         <varlistentry>
1076                                 <term><command>rescue</command></term>
1077
1078                                 <listitem><para>Enter rescue
1079                                 mode. This is mostly equivalent to
1080                                 <command>isolate
1081                                 rescue.target</command> but also
1082                                 prints a wall message to all
1083                                 users.</para></listitem>
1084                         </varlistentry>
1085                         <varlistentry>
1086                                 <term><command>emergency</command></term>
1087
1088                                 <listitem><para>Enter emergency
1089                                 mode. This is mostly equivalent to
1090                                 <command>isolate
1091                                 emergency.target</command> but also
1092                                 prints a wall message to all
1093                                 users.</para></listitem>
1094                         </varlistentry>
1095                         <varlistentry>
1096                                 <term><command>halt</command></term>
1097
1098                                 <listitem><para>Shut down and halt the
1099                                 system. This is mostly equivalent to
1100                                 <command>start halt.target</command>
1101                                 but also prints a wall message to all
1102                                 users.  If combined with
1103                                 <option>--force</option> shutdown of
1104                                 all running services is skipped,
1105                                 however all processes are killed and
1106                                 all file systems are unmounted or
1107                                 mounted read-only, immediately
1108                                 followed by the system halt.  If
1109                                 <option>--force</option> is specified
1110                                 twice the operation is immediately
1111                                 executed without terminating any
1112                                 processes or unmounting any file
1113                                 systems. This may result in data
1114                                 loss.</para></listitem>
1115                         </varlistentry>
1116                         <varlistentry>
1117                                 <term><command>poweroff</command></term>
1118
1119                                 <listitem><para>Shut down and
1120                                 power-off the system. This is mostly
1121                                 equivalent to <command>start
1122                                 poweroff.target</command> but also
1123                                 prints a wall message to all users. If
1124                                 combined with <option>--force</option>
1125                                 shutdown of all running services is
1126                                 skipped, however all processes are
1127                                 killed and all file systems are
1128                                 unmounted or mounted read-only,
1129                                 immediately followed by the powering
1130                                 off. If <option>--force</option> is
1131                                 specified twice the operation is
1132                                 immediately executed without
1133                                 terminating any processes or
1134                                 unmounting any file systems. This may
1135                                 result in data loss.</para></listitem>
1136                         </varlistentry>
1137                         <varlistentry>
1138                                 <term><command>reboot</command></term>
1139
1140                                 <listitem><para>Shut down and reboot
1141                                 the system. This is mostly equivalent
1142                                 to <command>start
1143                                 reboot.target</command> but also
1144                                 prints a wall message to all users. If
1145                                 combined with <option>--force</option>
1146                                 shutdown of all running services is
1147                                 skipped, however all processes are
1148                                 killed and all file systems are
1149                                 unmounted or mounted read-only,
1150                                 immediately followed by the reboot. If
1151                                 <option>--force</option> is specified
1152                                 twice the operation is immediately
1153                                 executed without terminating any
1154                                 processes or unmounting any file
1155                                 systems. This may result in data
1156                                 loss.</para></listitem>
1157                         </varlistentry>
1158                         <varlistentry>
1159                                 <term><command>kexec</command></term>
1160
1161                                 <listitem><para>Shut down and reboot
1162                                 the system via kexec. This is mostly
1163                                 equivalent to <command>start
1164                                 kexec.target</command> but also prints
1165                                 a wall message to all users. If
1166                                 combined with <option>--force</option>
1167                                 shutdown of all running services is
1168                                 skipped, however all processes are killed
1169                                 and all file systems are unmounted or
1170                                 mounted read-only, immediately
1171                                 followed by the
1172                                 reboot.</para></listitem>
1173                         </varlistentry>
1174                         <varlistentry>
1175                                 <term><command>exit</command></term>
1176
1177                                 <listitem><para>Ask the systemd
1178                                 manager to quit. This is only
1179                                 supported for user service managers
1180                                 (i.e. in conjunction with the
1181                                 <option>--user</option> option) and
1182                                 will fail otherwise.</para></listitem>
1183                         </varlistentry>
1184                         <varlistentry>
1185                                 <term><command>suspend</command></term>
1186
1187                                 <listitem><para>Suspend the system.</para></listitem>
1188                         </varlistentry>
1189                         <varlistentry>
1190                                 <term><command>hibernate</command></term>
1191
1192                                 <listitem><para>Hibernate the system.</para></listitem>
1193                         </varlistentry>
1194                         <varlistentry>
1195                                 <term><command>switch-root [ROOT] [INIT]</command></term>
1196
1197                                 <listitem><para>Switches to a
1198                                 different root directory and executes
1199                                 a new system manager process below
1200                                 it. This is intended for usage in
1201                                 initial RAM disks ("initrd"), and will
1202                                 transition from the initrd's system
1203                                 manager process (a.k.a "init" process)
1204                                 to the main system manager
1205                                 process. Takes two arguments: the
1206                                 directory to make the new root
1207                                 directory, and the path to the new
1208                                 system manager binary below it to
1209                                 execute as PID 1. If the latter is
1210                                 omitted or the empty string, a
1211                                 systemd binary will automatically be
1212                                 searched for and used as init. If the
1213                                 system manager path is omitted or
1214                                 equal the empty string the state of
1215                                 the initrd's system manager process is
1216                                 passed to the main system manager,
1217                                 which allows later introspection of the
1218                                 state of the services involved in the
1219                                 initrd boot.</para></listitem>
1220                         </varlistentry>
1221                 </variablelist>
1222
1223         </refsect1>
1224
1225         <refsect1>
1226                 <title>Exit status</title>
1227
1228                 <para>On success 0 is returned, a non-zero failure
1229                 code otherwise.</para>
1230         </refsect1>
1231
1232         <refsect1>
1233                 <title>Environment</title>
1234
1235                 <variablelist>
1236                         <varlistentry>
1237                                 <term><varname>$SYSTEMD_PAGER</varname></term>
1238                                 <listitem><para>Pager to use when
1239                                 <option>--no-pager</option> is not given;
1240                                 overrides <varname>$PAGER</varname>.  Setting
1241                                 this to an empty string or the value
1242                                 <literal>cat</literal> is equivalent to passing
1243                                 <option>--no-pager</option>.</para></listitem>
1244                         </varlistentry>
1245                 </variablelist>
1246         </refsect1>
1247
1248         <refsect1>
1249                 <title>See Also</title>
1250                 <para>
1251                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1252                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1253                         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1254                         <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1255                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1256                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1257                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1258                         <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1259                 </para>
1260         </refsect1>
1261
1262 </refentry>