man/systemctl.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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   6   This file is part of systemd.
   7
   8   Copyright 2010 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU 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
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 -->
  23
  24 <refentry id="systemctl">
  25
  26         <refentryinfo>
  27                 <title>systemctl</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>systemctl</refentrytitle>
  42                 <manvolnum>1</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemctl</refname>
  47                 <refpurpose>Control the systemd system and service manager</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <cmdsynopsis>
  52                         <command>systemctl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg> <arg choice="opt" rep="repeat">NAME</arg></command>
  53                 </cmdsynopsis>
  54         </refsynopsisdiv>
  55
  56         <refsect1>
  57                 <title>Description</title>
  58
  59                 <para><command>systemctl</command> may be used to
  60                 introspect and control the state of the
  61                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  62                 system and service manager.</para>
  63         </refsect1>
  64
  65         <refsect1>
  66                 <title>Options</title>
  67
  68                 <para>The following options are understood:</para>
  69
  70                 <variablelist>
  71                         <varlistentry>
  72                                 <term><option>--help</option></term>
  73                                 <term><option>-h</option></term>
  74
  75                                 <listitem><para>Prints a short help
  76                                 text and exits.</para></listitem>
  77                         </varlistentry>
  78
  79                         <varlistentry>
  80                                 <term><option>--version</option></term>
  81
  82                                 <listitem><para>Prints a short version
  83                                 string and exits.</para></listitem>
  84                         </varlistentry>
  85
  86                         <varlistentry>
  87                                 <term><option>--type=</option></term>
  88                                 <term><option>-t</option></term>
  89
  90                                 <listitem><para>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
 110                                 <para>As a special case, if the argument
 111                                 is <option>help</option>, a list of
 112                                 allowed values will be printed and the
 113                                 program will exit.</para>
 114                                 </listitem>
 115                         </varlistentry>
 116
 117                         <varlistentry>
 118                                 <term><option>--property=</option></term>
 119                                 <term><option>-p</option></term>
 120
 121                                 <listitem><para>When showing
 122                                 unit/job/manager properties, limit
 123                                 display to certain properties as
 124                                 specified as argument. If not
 125                                 specified all set properties are
 126                                 shown. The argument should be a
 127                                 property name, such as
 128                                 <literal>MainPID</literal>. If
 129                                 specified more than once all
 130                                 properties with the specified names
 131                                 are shown.</para></listitem>
 132                         </varlistentry>
 133
 134                         <varlistentry>
 135                                 <term><option>--all</option></term>
 136                                 <term><option>-a</option></term>
 137
 138                                 <listitem><para>When listing units,
 139                                 show all units, regardless of their
 140                                 state, including inactive units. When
 141                                 showing unit/job/manager properties,
 142                                 show all properties regardless whether
 143                                 they are set or not.</para></listitem>
 144                         </varlistentry>
 145
 146                         <varlistentry>
 147                                 <term><option>--failed</option></term>
 148
 149                                 <listitem><para>When listing units,
 150                                 show only failed units. Do not confuse
 151                                 with
 152                                 <option>--fail</option>.</para></listitem>
 153                         </varlistentry>
 154
 155                         <varlistentry>
 156                                 <term><option>--full</option></term>
 157
 158                                 <listitem><para>Do not ellipsize unit
 159                                 names and truncate unit descriptions
 160                                 in the output of
 161                                 <command>list-units</command> and
 162                                 <command>list-jobs</command>.</para></listitem>
 163                         </varlistentry>
 164
 165                         <varlistentry>
 166                                 <term><option>--fail</option></term>
 167
 168                                 <listitem><para>If the requested
 169                                 operation conflicts with a pending
 170                                 unfinished job, fail the command. If
 171                                 this is not specified the requested
 172                                 operation will replace the pending job,
 173                                 if necessary. Do not confuse
 174                                 with
 175                                 <option>--failed</option>.</para></listitem>
 176                         </varlistentry>
 177
 178                         <varlistentry>
 179                                 <term><option>--ignore-dependencies</option></term>
 180
 181                                 <listitem><para>When enqueuing a new
 182                                 job ignore all its dependencies and
 183                                 execute it immediately. If passed no
 184                                 required units of the unit passed will
 185                                 be pulled in, and no ordering
 186                                 dependencies will be honored. This is
 187                                 mostly a debugging and rescue tool for
 188                                 the administrator and should not be
 189                                 used by
 190                                 applications.</para></listitem>
 191                         </varlistentry>
 192
 193                         <varlistentry>
 194                                 <term><option>--quiet</option></term>
 195                                 <term><option>-q</option></term>
 196
 197                                 <listitem><para>Suppress output to
 198                                 STDOUT in
 199                                 <command>snapshot</command>,
 200                                 <command>is-active</command>,
 201                                 <command>is-failed</command>,
 202                                 <command>enable</command> and
 203                                 <command>disable</command>.</para></listitem>
 204                         </varlistentry>
 205
 206                         <varlistentry>
 207                                 <term><option>--no-block</option></term>
 208
 209                                 <listitem><para>Do not synchronously wait for
 210                                 the requested operation to finish. If this is
 211                                 not specified the job will be verified,
 212                                 enqueued and <command>systemctl</command> will
 213                                 wait until it is completed. By passing this
 214                                 argument it is only verified and
 215                                 enqueued.</para></listitem>
 216                         </varlistentry>
 217
 218                         <varlistentry>
 219                                 <term><option>--no-legend</option></term>
 220
 221                                 <listitem><para>Do not print a legend, i.e.
 222                                 the column headers and the footer with hints.
 223                                 </para></listitem>
 224                         </varlistentry>
 225
 226                         <varlistentry>
 227                                 <term><option>--no-pager</option></term>
 228
 229                                 <listitem><para>Do not pipe output into a
 230                                 pager.</para></listitem>
 231                         </varlistentry>
 232
 233                         <varlistentry>
 234                                 <term><option>--system</option></term>
 235
 236                                 <listitem><para>Talk to the systemd
 237                                 system manager. (Default)</para></listitem>
 238                         </varlistentry>
 239
 240                         <varlistentry>
 241                                 <term><option>--user</option></term>
 242
 243                                 <listitem><para>Talk to the systemd
 244                                 manager of the calling user.</para></listitem>
 245                         </varlistentry>
 246
 247                         <varlistentry>
 248                                 <term><option>--order</option></term>
 249                                 <term><option>--require</option></term>
 250
 251                                 <listitem><para>When used in
 252                                 conjunction with the
 253                                 <command>dot</command> command (see
 254                                 below), selects which dependencies are
 255                                 shown in the dependency graph. If
 256                                 <option>--order</option> is passed
 257                                 only dependencies of type
 258                                 <varname>After=</varname> or
 259                                 <varname>Before=</varname> are
 260                                 shown. If <option>--require</option>
 261                                 is passed only dependencies of type
 262                                 <varname>Requires=</varname>,
 263                                 <varname>RequiresOverridable=</varname>,
 264                                 <varname>Requisite=</varname>,
 265                                 <varname>RequisiteOverridable=</varname>,
 266                                 <varname>Wants=</varname> and
 267                                 <varname>Conflicts=</varname> are
 268                                 shown. If neither is passed, shows
 269                                 dependencies of all these
 270                                 types.</para></listitem>
 271                         </varlistentry>
 272
 273                         <varlistentry>
 274                                 <term><option>--no-wall</option></term>
 275
 276                                 <listitem><para>Don't send wall
 277                                 message before
 278                                 halt, power-off, reboot.</para></listitem>
 279                         </varlistentry>
 280
 281                         <varlistentry>
 282                                 <term><option>--global</option></term>
 283
 284                                 <listitem><para>When used with
 285                                 <command>enable</command> and
 286                                 <command>disable</command>, operate on the
 287                                 global user configuration
 288                                 directory, thus enabling or disabling
 289                                 a unit file globally for all future
 290                                 logins of all users.</para></listitem>
 291                         </varlistentry>
 292
 293                         <varlistentry>
 294                                 <term><option>--no-reload</option></term>
 295
 296                                 <listitem><para>When used with
 297                                 <command>enable</command> and
 298                                 <command>disable</command>, do not
 299                                 implicitly reload daemon configuration
 300                                 after executing the
 301                                 changes.</para></listitem>
 302                         </varlistentry>
 303
 304                         <varlistentry>
 305                                 <term><option>--no-ask-password</option></term>
 306
 307                                 <listitem><para>When used with
 308                                 <command>start</command> and related
 309                                 commands, disables asking for
 310                                 passwords. Background services may
 311                                 require input of a password or
 312                                 passphrase string, for example to
 313                                 unlock system hard disks or
 314                                 cryptographic certificates. Unless
 315                                 this option is specified and the
 316                                 command is invoked from a terminal
 317                                 <command>systemctl</command> will
 318                                 query the user on the terminal for the
 319                                 necessary secrets. Use this option to
 320                                 switch this behavior off. In this case
 321                                 the password must be supplied by some
 322                                 other means (for example graphical
 323                                 password agents) or the service might
 324                                 fail. This also disables querying the
 325                                 user for authentication for privileged
 326                                 operations.</para></listitem>
 327                         </varlistentry>
 328
 329                         <varlistentry>
 330                                 <term><option>--kill-who=</option></term>
 331
 332                                 <listitem><para>When used with
 333                                 <command>kill</command>, choose which
 334                                 processes to kill. Must be one of
 335                                 <option>main</option>,
 336                                 <option>control</option> or
 337                                 <option>all</option> to select whether
 338                                 to kill only the main process of the
 339                                 unit, the control process or all
 340                                 processes of the unit. If omitted
 341                                 defaults to
 342                                 <option>all</option>.</para></listitem>
 343                         </varlistentry>
 344
 345                         <varlistentry>
 346                                 <term><option>--signal=</option></term>
 347                                 <term><option>-s</option></term>
 348
 349                                 <listitem><para>When used with
 350                                 <command>kill</command>, choose which
 351                                 signal to send to selected
 352                                 processes. Must be one of the well
 353                                 known signal specifiers such as
 354                                 SIGTERM, SIGINT or SIGSTOP. If
 355                                 omitted defaults to
 356                                 <option>SIGTERM</option>.</para></listitem>
 357                         </varlistentry>
 358
 359                         <varlistentry>
 360                                 <term><option>--force</option></term>
 361                                 <term><option>-f</option></term>
 362
 363                                 <listitem><para>When used with
 364                                 <command>enable</command>, overwrite any
 365                                 existing conflicting
 366                                 symlinks.</para></listitem>
 367
 368                                 <listitem><para>When used with
 369                                 <command>halt</command>,
 370                                 <command>poweroff</command>,
 371                                 <command>reboot</command> or
 372                                 <command>kexec</command> execute the
 373                                 selected operation without shutting
 374                                 down all units. However, all processes
 375                                 will be killed forcibly and all file
 376                                 systems are unmounted or remounted
 377                                 read-only. This is hence a drastic but
 378                                 relatively safe option to request an
 379                                 immediate reboot. If
 380                                 <option>--force</option> is specified
 381                                 twice for these operations, they will
 382                                 be executed immediately without
 383                                 terminating any processes or umounting
 384                                 any file systems. Warning: specifying
 385                                 <option>--force</option> twice with
 386                                 any of these operations might result
 387                                 in data loss.</para></listitem>
 388                         </varlistentry>
 389
 390                         <varlistentry>
 391                                 <term><option>--root=</option></term>
 392
 393                                 <listitem><para>When used with
 394                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and
 395                                 related commands), use alternative
 396                                 root path when looking for unit
 397                                 files.</para></listitem>
 398                         </varlistentry>
 399
 400                         <varlistentry>
 401                                 <term><option>--runtime</option></term>
 402
 403                                 <listitem><para>When used with
 404                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and related commands), make
 405                                 changes only temporarily, so that they
 406                                 are dropped on the next reboot. This
 407                                 will have the effect that changes are
 408                                 not made in subdirectories of
 409                                 <filename>/etc</filename> but in
 410                                 <filename>/run</filename>, with
 411                                 identical immediate effects, however,
 412                                 since the latter is lost on reboot,
 413                                 the changes are lost
 414                                 too.</para></listitem>
 415                         </varlistentry>
 416
 417                         <varlistentry>
 418                                 <term><option>-H</option></term>
 419                                 <term><option>--host</option></term>
 420
 421                                 <listitem><para>Execute operation
 422                                 remotely. Specify a hostname, or
 423                                 username and hostname separated by @,
 424                                 to connect to. This will use SSH to
 425                                 talk to the remote systemd
 426                                 instance.</para></listitem>
 427                         </varlistentry>
 428
 429                         <varlistentry>
 430                                 <term><option>-P</option></term>
 431                                 <term><option>--privileged</option></term>
 432
 433                                 <listitem><para>Acquire privileges via
 434                                 PolicyKit before executing the
 435                                 operation.</para></listitem>
 436                         </varlistentry>
 437
 438                         <varlistentry>
 439                                 <term><option>--lines=</option></term>
 440                                 <term><option>-n</option></term>
 441
 442                                 <listitem><para>When used with
 443                                 <command>status</command> controls the
 444                                 number of journal lines to show,
 445                                 counting from the most recent
 446                                 ones. Takes a positive integer
 447                                 argument. Defaults to
 448                                 10.</para></listitem>
 449                         </varlistentry>
 450
 451                         <varlistentry>
 452                                 <term><option>--output=</option></term>
 453                                 <term><option>-o</option></term>
 454
 455                                 <listitem><para>When used with
 456                                 <command>status</command> controls the
 457                                 formatting of the journal entries that
 458                                 are shown. For the available choices
 459                                 see
 460                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Defaults
 461                                 to
 462                                 <literal>short</literal>.</para></listitem>
 463                         </varlistentry>
 464
 465                 </variablelist>
 466
 467                 <para>The following commands are understood:</para>
 468
 469                 <variablelist>
 470                         <varlistentry>
 471                                 <term><command>list-units</command></term>
 472
 473                                 <listitem><para>List known units.</para></listitem>
 474                         </varlistentry>
 475                         <varlistentry>
 476                                 <term><command>start [NAME...]</command></term>
 477
 478                                 <listitem><para>Start (activate) one
 479                                 or more units specified on the command
 480                                 line.</para></listitem>
 481                         </varlistentry>
 482                         <varlistentry>
 483                                 <term><command>stop [NAME...]</command></term>
 484
 485                                 <listitem><para>Stop (deactivate) one
 486                                 or more units specified on the command
 487                                 line.</para></listitem>
 488                         </varlistentry>
 489                         <varlistentry>
 490                                 <term><command>reload [NAME...]</command></term>
 491
 492                                 <listitem><para>Asks all units listed
 493                                 on the command line to reload their
 494                                 configuration. Note that this will
 495                                 reload the service-specific
 496                                 configuration, not the unit
 497                                 configuration file of systemd. If you
 498                                 want systemd to reload the
 499                                 configuration file of a unit use the
 500                                 <command>daemon-reload</command>
 501                                 command. In other words: for the
 502                                 example case of Apache, this will
 503                                 reload Apache's
 504                                 <filename>httpd.conf</filename> in the
 505                                 web server, not the
 506                                 <filename>apache.service</filename>
 507                                 systemd unit file. </para>
 508
 509                                 <para>This command should not be
 510                                 confused with the
 511                                 <command>daemon-reload</command> or
 512                                 <command>load</command>
 513                                 commands.</para></listitem>
 514
 515                         </varlistentry>
 516                         <varlistentry>
 517                                 <term><command>restart [NAME...]</command></term>
 518
 519                                 <listitem><para>Restart one or more
 520                                 units specified on the command
 521                                 line. If the units are not running yet
 522                                 they will be
 523                                 started.</para></listitem>
 524                         </varlistentry>
 525                         <varlistentry>
 526                                 <term><command>try-restart [NAME...]</command></term>
 527
 528                                 <listitem><para>Restart one or more
 529                                 units specified on the command
 530                                 line if the units are running. Do
 531                                 nothing if units are not running.
 532                                 Note that for compatibility
 533                                 with Red Hat init scripts
 534                                 <command>condrestart</command> is
 535                                 equivalent to this command.</para></listitem>
 536                         </varlistentry>
 537                         <varlistentry>
 538                                 <term><command>reload-or-restart [NAME...]</command></term>
 539
 540                                 <listitem><para>Reload one or more
 541                                 units if they support it. If not,
 542                                 restart them instead. If the units
 543                                 are not running yet they will be
 544                                 started.</para></listitem>
 545                         </varlistentry>
 546                         <varlistentry>
 547                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 548
 549                                 <listitem><para>Reload one or more
 550                                 units if they support it. If not,
 551                                 restart them instead. Do nothing if
 552                                 the units are not running. Note that
 553                                 for compatibility with SysV init
 554                                 scripts
 555                                 <command>force-reload</command> is
 556                                 equivalent to this
 557                                 command.</para></listitem>
 558                         </varlistentry>
 559                         <varlistentry>
 560                                 <term><command>isolate [NAME]</command></term>
 561
 562                                 <listitem><para>Start the unit
 563                                 specified on the command line and its
 564                                 dependencies and stop all others.</para>
 565
 566                                 <para>This is similar to changing the
 567                                 runlevel in a traditional init system. The
 568                                 <command>isolate</command> command will
 569                                 immediately stop processes that are not
 570                                 enabled in the new unit, possibly including
 571                                 the graphical environment or terminal you
 572                                 are currently using.</para>
 573
 574                                 <para>Note that this works only on units
 575                                 where <option>AllowIsolate=</option> is
 576                                 enabled. See
 577                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 578                                 for details.</para></listitem>
 579                         </varlistentry>
 580                         <varlistentry>
 581                                 <term><command>kill [NAME...]</command></term>
 582
 583                                 <listitem><para>Send a signal to one
 584                                 or more processes of the unit. Use
 585                                 <option>--kill-who=</option> to select
 586                                 which process to kill. Use
 587                                 <option>--kill-mode=</option> to
 588                                 select the kill mode and
 589                                 <option>--signal=</option> to select
 590                                 the signal to send.</para></listitem>
 591                         </varlistentry>
 592                         <varlistentry>
 593                                 <term><command>is-active [NAME...]</command></term>
 594
 595                                 <listitem><para>Check whether any of
 596                                 the specified units are active
 597                                 (i.e. running). Returns an exit code
 598                                 0 if at least one is active, non-zero
 599                                 otherwise. Unless
 600                                 <option>--quiet</option> is specified
 601                                 this will also print the current unit
 602                                 state to STDOUT.</para></listitem>
 603                         </varlistentry>
 604                         <varlistentry>
 605                                 <term><command>is-failed [NAME...]</command></term>
 606
 607                                 <listitem><para>Check whether any of
 608                                 the specified units are failed.
 609                                 Returns an exit code
 610                                 0 if at least one is failed, non-zero
 611                                 otherwise. Unless
 612                                 <option>--quiet</option> is specified
 613                                 this will also print the current unit
 614                                 state to STDOUT.</para></listitem>
 615                         </varlistentry>
 616                         <varlistentry>
 617                                 <term><command>status [NAME...|PID...]</command></term>
 618
 619                                 <listitem><para>Show terse runtime
 620                                 status information about one or more
 621                                 units, followed by its most recent log
 622                                 data from the journal. This function
 623                                 is intended to generate human-readable
 624                                 output. If you are looking for
 625                                 computer-parsable output, use
 626                                 <command>show</command> instead. If a
 627                                 PID is passed information about the
 628                                 unit the process of the PID belongs to
 629                                 is shown.</para></listitem>
 630                         </varlistentry>
 631                         <varlistentry>
 632                                 <term><command>show [NAME...|JOB...]</command></term>
 633
 634                                 <listitem><para>Show properties of one
 635                                 or more units, jobs or the manager
 636                                 itself. If no argument is specified
 637                                 properties of the manager will be
 638                                 shown. If a unit name is specified
 639                                 properties of the unit is shown, and
 640                                 if a job id is specified properties of
 641                                 the job is shown. By default, empty
 642                                 properties are suppressed. Use
 643                                 <option>--all</option> to show those
 644                                 too. To select specific properties to
 645                                 show use
 646                                 <option>--property=</option>. This
 647                                 command is intended to be used
 648                                 whenever computer-parsable output is
 649                                 required. Use
 650                                 <command>status</command> if you are
 651                                 looking for formatted human-readable
 652                                 output.</para></listitem>
 653                         </varlistentry>
 654                         <varlistentry>
 655                                 <term><command>help [NAME...|PID...]</command></term>
 656
 657                                 <listitem><para>Show manual pages for
 658                                 one or more units, if available. If a
 659                                 PID is passed the manual pages for the
 660                                 unit the process of the PID belongs to
 661                                 is shown.</para></listitem>
 662                         </varlistentry>
 663                         <varlistentry>
 664                                 <term><command>reset-failed [NAME...]</command></term>
 665
 666                                 <listitem><para>Reset the
 667                                 '<literal>failed</literal>' state of the
 668                                 specified units, or if no unit name is
 669                                 passed of all units. When a unit fails
 670                                 in some way (i.e. process exiting with
 671                                 non-zero error code, terminating
 672                                 abnormally or timing out) it will
 673                                 automatically enter the
 674                                 '<literal>failed</literal>' state and
 675                                 its exit code and status is recorded
 676                                 for introspection by the administrator
 677                                 until the service is restarted or
 678                                 reset with this
 679                                 command.</para></listitem>
 680                         </varlistentry>
 681
 682                         <varlistentry>
 683                                 <term><command>list-unit-files</command></term>
 684
 685                                 <listitem><para>List installed unit files.
 686                                 </para></listitem>
 687                         </varlistentry>
 688
 689                         <varlistentry>
 690                                 <term><command>enable [NAME...]</command></term>
 691
 692                                 <listitem><para>Enable one or
 693                                 more unit files or unit file
 694                                 instances, as specified on the
 695                                 command line. This will create a
 696                                 number of symlinks as encoded in
 697                                 the <literal>[Install]</literal>
 698                                 sections of the unit files. After
 699                                 the symlinks have been created the
 700                                 systemd configuration is reloaded
 701                                 (in a way that is equivalent to
 702                                 <command>daemon-reload</command>)
 703                                 to ensure the changes are taken into
 704                                 account immediately. Note that this
 705                                 does not have the effect that any of
 706                                 the units enabled are also started at
 707                                 the same time.  If this is desired
 708                                 a separate <command>start</command>
 709                                 command must be invoked for the unit.
 710                                 Also note that in case of instance
 711                                 enablement, symlinks named same as
 712                                 instances are created in install
 713                                 location, however they all point to
 714                                 the same template unit file.</para>
 715
 716                                 <para>This command will
 717                                 print the actions executed. This
 718                                 output may be suppressed by passing
 719                                 <option>--quiet</option>.</para>
 720
 721                                 <para>Note that this operation creates
 722                                 only the suggested symlinks for the
 723                                 units. While this command is the
 724                                 recommended way to manipulate the unit
 725                                 configuration directory, the
 726                                 administrator is free to make
 727                                 additional changes manually, by
 728                                 placing or removing symlinks in the
 729                                 directory. This is particularly useful
 730                                 to create configurations that deviate
 731                                 from the suggested default
 732                                 installation. In this case the
 733                                 administrator must make sure to invoke
 734                                 <command>daemon-reload</command>
 735                                 manually as necessary, to ensure his
 736                                 changes are taken into account.</para>
 737
 738                                 <para>Enabling units should not be
 739                                 confused with starting (activating)
 740                                 units, as done by the
 741                                 <command>start</command>
 742                                 command. Enabling and starting units
 743                                 is orthogonal: units may be enabled
 744                                 without being started and started
 745                                 without being enabled. Enabling simply
 746                                 hooks the unit into various suggested
 747                                 places (for example, so that the unit
 748                                 is automatically started on boot or
 749                                 when a particular kind of hardware is
 750                                 plugged in). Starting actually spawns
 751                                 the daemon process (in case of service
 752                                 units), or binds the socket (in case
 753                                 of socket units), and so
 754                                 on.</para>
 755
 756                                 <para>Depending on whether
 757                                 <option>--system</option>,
 758                                 <option>--user</option> or
 759                                 <option>--global</option> is specified
 760                                 this enables the unit for the system,
 761                                 for the calling user only
 762                                 or for all future logins of all
 763                                 users. Note that in the latter case no
 764                                 systemd daemon configuration is
 765                                 reloaded.</para>
 766                                 </listitem>
 767                         </varlistentry>
 768
 769                         <varlistentry>
 770                                 <term><command>disable [NAME...]</command></term>
 771
 772                                 <listitem><para>Disables one or more
 773                                 units. This removes all symlinks to
 774                                 the specified unit files from the unit
 775                                 configuration directory, and hence
 776                                 undoes the changes made by
 777                                 <command>enable</command>. Note
 778                                 however that this removes
 779                                 all symlinks to the unit files
 780                                 (i.e. including manual additions), not
 781                                 just those actually created by
 782                                 <command>enable</command>. This call
 783                                 implicitly reloads the systemd daemon
 784                                 configuration after completing the
 785                                 disabling of the units. Note that this
 786                                 command does not implicitly stop the
 787                                 units that are being disabled. If this
 788                                 is desired an additional
 789                                 <command>stop</command> command should
 790                                 be executed afterwards.</para>
 791
 792                                 <para>This command will print the
 793                                 actions executed. This output may be
 794                                 suppressed by passing
 795                                 <option>--quiet</option>.</para>
 796                                 </listitem>
 797
 798                                 <para>This command honors
 799                                 <option>--system</option>,
 800                                 <option>--user</option>,
 801                                 <option>--global</option> in a similar
 802                                 way as
 803                                 <command>enable</command>.</para>
 804                         </varlistentry>
 805
 806                         <varlistentry>
 807                                 <term><command>is-enabled [NAME...]</command></term>
 808
 809                                 <listitem><para>Checks whether any of
 810                                 the specified unit files are enabled
 811                                 (as with
 812                                 <command>enable</command>). Returns an
 813                                 exit code of 0 if at least one is
 814                                 enabled, non-zero otherwise. Prints
 815                                 the current enable status. To suppress
 816                                 this output use
 817                                 <option>--quiet</option>.</para></listitem>
 818                         </varlistentry>
 819
 820                         <varlistentry>
 821                                 <term><command>reenable [NAME...]</command></term>
 822
 823                                 <listitem><para>Reenable one or more
 824                                 unit files, as specified on the
 825                                 command line. This is a combination of
 826                                 <command>disable</command> and
 827                                 <command>enable</command> and is
 828                                 useful to reset the symlinks a unit is
 829                                 enabled with to the defaults
 830                                 configured in the
 831                                 <literal>[Install]</literal> section
 832                                 of the unit file.</para>
 833                                 </listitem>
 834                         </varlistentry>
 835
 836                         <varlistentry>
 837                                 <term><command>preset [NAME...]</command></term>
 838
 839                                 <listitem><para>Reset one or more unit
 840                                 files, as specified on the command
 841                                 line, to the defaults configured in
 842                                 the preset policy files. This has the
 843                                 same effect as
 844                                 <command>disable</command> or
 845                                 <command>enable</command>, depending
 846                                 how the unit is listed in the preset
 847                                 files. For more information on preset
 848                                 policy format see
 849                                 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 850                                 more information on the concept of
 851                                 presets please consult the <ulink
 852                                 url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
 853                                 document.</para>
 854                                 </listitem>
 855                         </varlistentry>
 856
 857                         <varlistentry>
 858                                 <term><command>mask [NAME...]</command></term>
 859
 860                                 <listitem><para>Mask one or more unit
 861                                 files, as specified on the command
 862                                 line. This will link these units to
 863                                 <filename>/dev/null</filename>, making
 864                                 it impossible to start them. This is a stronger version
 865                                 of <command>disable</command>, since
 866                                 it prohibits all kinds of activation
 867                                 of the unit, including manual
 868                                 activation. Use this option with
 869                                 care.</para>
 870                                 </listitem>
 871                         </varlistentry>
 872
 873                         <varlistentry>
 874                                 <term><command>unmask [NAME...]</command></term>
 875
 876                                 <listitem><para>Unmask one or more
 877                                 unit files, as specified on the
 878                                 command line. This will undo the
 879                                 effect of
 880                                 <command>mask</command>.</para>
 881                                 </listitem>
 882                         </varlistentry>
 883
 884                         <varlistentry>
 885                                 <term><command>link [NAME...]</command></term>
 886
 887                                 <listitem><para>Link a unit file that
 888                                 is not in the unit file search paths
 889                                 into the unit file search path. This
 890                                 requires an absolute path to a unit
 891                                 file. The effect of this can be undone
 892                                 with <command>disable</command>. The
 893                                 effect of this command is that a unit
 894                                 file is available for
 895                                 <command>start</command> and other
 896                                 commands although it isn't installed
 897                                 directly in the unit search
 898                                 path.</para>
 899                                 </listitem>
 900                         </varlistentry>
 901
 902                         <varlistentry>
 903                                 <term><command>load [NAME...]</command></term>
 904
 905                                 <listitem><para>Load one or more units
 906                                 specified on the command line. This
 907                                 will simply load their configuration
 908                                 from disk, but not start them. To
 909                                 start them you need to use the
 910                                 <command>start</command> command which
 911                                 will implicitly load a unit that has
 912                                 not been loaded yet. Note that systemd
 913                                 garbage collects loaded units that are
 914                                 not active or referenced by an active
 915                                 unit. This means that units loaded
 916                                 this way will usually not stay loaded
 917                                 for long. Also note that this command
 918                                 cannot be used to reload unit
 919                                 configuration. Use the
 920                                 <command>daemon-reload</command>
 921                                 command for that. All in all, this
 922                                 command is of little use except for
 923                                 debugging.</para>
 924                                 <para>This command should not be
 925                                 confused with the
 926                                 <command>daemon-reload</command> or
 927                                 <command>reload</command>
 928                                 commands.</para></listitem>
 929                         </varlistentry>
 930                         <varlistentry>
 931                                 <term><command>list-jobs</command></term>
 932
 933                                 <listitem><para>List jobs that are in progress.</para></listitem>
 934                         </varlistentry>
 935                         <varlistentry>
 936                                 <term><command>cancel [JOB...]</command></term>
 937
 938                                 <listitem><para>Cancel one or more
 939                                 jobs specified on the command line by
 940                                 their numeric job
 941                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 942                         </varlistentry>
 943                         <varlistentry>
 944                                 <term><command>dump</command></term>
 945
 946                                 <listitem><para>Dump server
 947                                 status. This will output a (usually
 948                                 very long) human readable manager
 949                                 status dump. Its format is subject to
 950                                 change without notice and should not
 951                                 be parsed by
 952                                 applications.</para></listitem>
 953                         </varlistentry>
 954                         <varlistentry>
 955                                 <term><command>dot</command></term>
 956
 957                                 <listitem><para>Generate textual
 958                                 dependency graph description in dot
 959                                 format for further processing with the
 960                                 GraphViz
 961                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 962                                 tool. Use a command line like
 963                                 <command>systemctl dot | dot -Tsvg >
 964                                 systemd.svg</command> to generate a
 965                                 graphical dependency tree. Unless
 966                                 <option>--order</option> or
 967                                 <option>--require</option> is passed
 968                                 the generated graph will show both
 969                                 ordering and requirement
 970                                 dependencies.</para></listitem>
 971                         </varlistentry>
 972                         <varlistentry>
 973                                 <term><command>snapshot [NAME]</command></term>
 974
 975                                 <listitem><para>Create a snapshot. If
 976                                 a snapshot name is specified, the new
 977                                 snapshot will be named after it. If
 978                                 none is specified an automatic
 979                                 snapshot name is generated. In either
 980                                 case, the snapshot name used is
 981                                 printed to STDOUT, unless
 982                                 <option>--quiet</option> is
 983                                 specified.</para>
 984
 985                                 <para>A snapshot refers to a saved
 986                                 state of the systemd manager. It is
 987                                 implemented itself as a unit that is
 988                                 generated dynamically with this
 989                                 command and has dependencies on all
 990                                 units active at the time. At a later
 991                                 time the user may return to this state
 992                                 by using the
 993                                 <command>isolate</command> command on
 994                                 the snapshot unit.</para></listitem>
 995
 996                                 <para>Snapshots are only useful for
 997                                 saving and restoring which units are
 998                                 running or are stopped, they do not
 999                                 save/restore any other
1000                                 state. Snapshots are dynamic and lost
1001                                 on reboot.</para>
1002                         </varlistentry>
1003                         <varlistentry>
1004                                 <term><command>delete [NAME...]</command></term>
1005
1006                                 <listitem><para>Remove a snapshot
1007                                 previously created with
1008                                 <command>snapshot</command>.</para></listitem>
1009                         </varlistentry>
1010                         <varlistentry>
1011                                 <term><command>daemon-reload</command></term>
1012
1013                                 <listitem><para>Reload systemd manager
1014                                 configuration. This will reload all
1015                                 unit files and recreate the entire
1016                                 dependency tree. While the daemon is
1017                                 reloaded, all sockets systemd listens
1018                                 on on behalf of user configuration will
1019                                 stay accessible.</para> <para>This
1020                                 command should not be confused with
1021                                 the <command>load</command> or
1022                                 <command>reload</command>
1023                                 commands.</para></listitem>
1024                         </varlistentry>
1025                         <varlistentry>
1026                                 <term><command>daemon-reexec</command></term>
1027
1028                                 <listitem><para>Reexecute the systemd
1029                                 manager. This will serialize the
1030                                 manager state, reexecute the process
1031                                 and deserialize the state again. This
1032                                 command is of little use except for
1033                                 debugging and package
1034                                 upgrades. Sometimes it might be
1035                                 helpful as a heavy-weight
1036                                 <command>daemon-reload</command>. While
1037                                 the daemon is reexecuted all sockets
1038                                 systemd listens on on behalf of user
1039                                 configuration will stay
1040                                 accessible.</para></listitem>
1041                         </varlistentry>
1042                         <varlistentry>
1043                                 <term><command>show-environment</command></term>
1044
1045                                 <listitem><para>Dump the systemd
1046                                 manager environment block. The
1047                                 environment block will be dumped in
1048                                 straight-forward form suitable for
1049                                 sourcing into a shell script. This
1050                                 environment block will be passed to
1051                                 all processes the manager
1052                                 spawns.</para></listitem>
1053                         </varlistentry>
1054                         <varlistentry>
1055                                 <term><command>set-environment [NAME=VALUE...]</command></term>
1056
1057                                 <listitem><para>Set one or more
1058                                 systemd manager environment variables,
1059                                 as specified on the command
1060                                 line.</para></listitem>
1061                         </varlistentry>
1062                         <varlistentry>
1063                                 <term><command>unset-environment [NAME...]</command></term>
1064
1065                                 <listitem><para>Unset one or more
1066                                 systemd manager environment
1067                                 variables. If only a variable name is
1068                                 specified it will be removed
1069                                 regardless of its value. If a variable
1070                                 and a value are specified the variable
1071                                 is only removed if it has the
1072                                 specified value.</para></listitem>
1073                         </varlistentry>
1074                         <varlistentry>
1075                                 <term><command>default</command></term>
1076
1077                                 <listitem><para>Enter default
1078                                 mode. This is mostly equivalent to
1079                                 <command>start
1080                                 default.target</command>.</para></listitem>
1081                         </varlistentry>
1082                         <varlistentry>
1083                                 <term><command>rescue</command></term>
1084
1085                                 <listitem><para>Enter rescue
1086                                 mode. This is mostly equivalent to
1087                                 <command>isolate
1088                                 rescue.target</command> but also
1089                                 prints a wall message to all
1090                                 users.</para></listitem>
1091                         </varlistentry>
1092                         <varlistentry>
1093                                 <term><command>emergency</command></term>
1094
1095                                 <listitem><para>Enter emergency
1096                                 mode. This is mostly equivalent to
1097                                 <command>isolate
1098                                 emergency.target</command> but also
1099                                 prints a wall message to all
1100                                 users.</para></listitem>
1101                         </varlistentry>
1102                         <varlistentry>
1103                                 <term><command>halt</command></term>
1104
1105                                 <listitem><para>Shut down and halt the
1106                                 system. This is mostly equivalent to
1107                                 <command>start halt.target</command>
1108                                 but also prints a wall message to all
1109                                 users.  If combined with
1110                                 <option>--force</option> shutdown of
1111                                 all running services is skipped,
1112                                 however all processes are killed and
1113                                 all file systems are unmounted or
1114                                 mounted read-only, immediately
1115                                 followed by the system halt.  If
1116                                 <option>--force</option> is specified
1117                                 twice the operation is immediately
1118                                 executed without terminating any
1119                                 processes or unmounting any file
1120                                 systems. This may result in data
1121                                 loss.</para></listitem>
1122                         </varlistentry>
1123                         <varlistentry>
1124                                 <term><command>poweroff</command></term>
1125
1126                                 <listitem><para>Shut down and
1127                                 power-off the system. This is mostly
1128                                 equivalent to <command>start
1129                                 poweroff.target</command> but also
1130                                 prints a wall message to all users. If
1131                                 combined with <option>--force</option>
1132                                 shutdown of all running services is
1133                                 skipped, however all processes are
1134                                 killed and all file systems are
1135                                 unmounted or mounted read-only,
1136                                 immediately followed by the powering
1137                                 off. If <option>--force</option> is
1138                                 specified twice the operation is
1139                                 immediately executed without
1140                                 terminating any processes or
1141                                 unmounting any file systems. This may
1142                                 result in data loss.</para></listitem>
1143                         </varlistentry>
1144                         <varlistentry>
1145                                 <term><command>reboot</command></term>
1146
1147                                 <listitem><para>Shut down and reboot
1148                                 the system. This is mostly equivalent
1149                                 to <command>start
1150                                 reboot.target</command> but also
1151                                 prints a wall message to all users. If
1152                                 combined with <option>--force</option>
1153                                 shutdown of all running services is
1154                                 skipped, however all processes are
1155                                 killed and all file systems are
1156                                 unmounted or mounted read-only,
1157                                 immediately followed by the reboot. If
1158                                 <option>--force</option> is specified
1159                                 twice the operation is immediately
1160                                 executed without terminating any
1161                                 processes or unmounting any file
1162                                 systems. This may result in data
1163                                 loss.</para></listitem>
1164                         </varlistentry>
1165                         <varlistentry>
1166                                 <term><command>kexec</command></term>
1167
1168                                 <listitem><para>Shut down and reboot
1169                                 the system via kexec. This is mostly
1170                                 equivalent to <command>start
1171                                 kexec.target</command> but also prints
1172                                 a wall message to all users. If
1173                                 combined with <option>--force</option>
1174                                 shutdown of all running services is
1175                                 skipped, however all processes are killed
1176                                 and all file systems are unmounted or
1177                                 mounted read-only, immediately
1178                                 followed by the
1179                                 reboot.</para></listitem>
1180                         </varlistentry>
1181                         <varlistentry>
1182                                 <term><command>exit</command></term>
1183
1184                                 <listitem><para>Ask the systemd
1185                                 manager to quit. This is only
1186                                 supported for user service managers
1187                                 (i.e. in conjunction with the
1188                                 <option>--user</option> option) and
1189                                 will fail otherwise.</para></listitem>
1190                         </varlistentry>
1191                         <varlistentry>
1192                                 <term><command>suspend</command></term>
1193
1194                                 <listitem><para>Suspend the
1195                                 system. This will trigger activation
1196                                 of the special
1197                                 <filename>suspend.target</filename>
1198                                 target.</para></listitem>
1199                         </varlistentry>
1200                         <varlistentry>
1201                                 <term><command>hibernate</command></term>
1202
1203                                 <listitem><para>Hibernate the
1204                                 system. This will trigger activation
1205                                 of the special
1206                                 <filename>hibernate.target</filename>
1207                                 target.</para></listitem>
1208                         </varlistentry>
1209                         <varlistentry>
1210                                 <term><command>hybrid-sleep</command></term>
1211
1212                                 <listitem><para>Hibernate and suspend
1213                                 the system. This will trigger
1214                                 activation of the special
1215                                 <filename>hybrid-sleep.target</filename>
1216                                 target.</para></listitem>
1217                         </varlistentry>
1218                         <varlistentry>
1219                                 <term><command>switch-root [ROOT] [INIT]</command></term>
1220
1221                                 <listitem><para>Switches to a
1222                                 different root directory and executes
1223                                 a new system manager process below
1224                                 it. This is intended for usage in
1225                                 initial RAM disks ("initrd"), and will
1226                                 transition from the initrd's system
1227                                 manager process (a.k.a "init" process)
1228                                 to the main system manager
1229                                 process. Takes two arguments: the
1230                                 directory to make the new root
1231                                 directory, and the path to the new
1232                                 system manager binary below it to
1233                                 execute as PID 1. If the latter is
1234                                 omitted or the empty string, a
1235                                 systemd binary will automatically be
1236                                 searched for and used as init. If the
1237                                 system manager path is omitted or
1238                                 equal the empty string the state of
1239                                 the initrd's system manager process is
1240                                 passed to the main system manager,
1241                                 which allows later introspection of the
1242                                 state of the services involved in the
1243                                 initrd boot.</para></listitem>
1244                         </varlistentry>
1245                 </variablelist>
1246
1247         </refsect1>
1248
1249         <refsect1>
1250                 <title>Exit status</title>
1251
1252                 <para>On success 0 is returned, a non-zero failure
1253                 code otherwise.</para>
1254         </refsect1>
1255
1256         <refsect1>
1257                 <title>Environment</title>
1258
1259                 <variablelist>
1260                         <varlistentry>
1261                                 <term><varname>$SYSTEMD_PAGER</varname></term>
1262                                 <listitem><para>Pager to use when
1263                                 <option>--no-pager</option> is not given;
1264                                 overrides <varname>$PAGER</varname>.  Setting
1265                                 this to an empty string or the value
1266                                 <literal>cat</literal> is equivalent to passing
1267                                 <option>--no-pager</option>.</para></listitem>
1268                         </varlistentry>
1269                 </variablelist>
1270         </refsect1>
1271
1272         <refsect1>
1273                 <title>See Also</title>
1274                 <para>
1275                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1276                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1277                         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1278                         <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1279                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1280                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1281                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1282                         <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1283                 </para>
1284         </refsect1>
1285
1286 </refentry>