man/systemctl.xml

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   8   Copyright 2010 Lennart Poettering
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  23
  24 <refentry id="systemctl">
  25
  26         <refentryinfo>
  27                 <title>systemctl</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>systemctl</refentrytitle>
  42                 <manvolnum>1</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemctl</refname>
  47                 <refpurpose>Control the systemd system and service manager</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <cmdsynopsis>
  52                         <command>systemctl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg> <arg choice="opt" rep="repeat">NAME</arg></command>
  53                 </cmdsynopsis>
  54         </refsynopsisdiv>
  55
  56         <refsect1>
  57                 <title>Description</title>
  58
  59                 <para><command>systemctl</command> may be used to
  60                 introspect and control the state of the
  61                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  62                 system and service manager.</para>
  63         </refsect1>
  64
  65         <refsect1>
  66                 <title>Options</title>
  67
  68                 <para>The following options are understood:</para>
  69
  70                 <variablelist>
  71                         <varlistentry>
  72                                 <term><option>-h</option></term>
  73                                 <term><option>--help</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>-t</option></term>
  88                                 <term><option>--type=</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>-p</option></term>
 119                                 <term><option>--property=</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>-a</option></term>
 136                                 <term><option>--all</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, cgroup members, 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>-i</option></term>
 195                                 <term><option>--ignore-inhibitors</option></term>
 196
 197                                 <listitem><para>When system shutdown
 198                                 or a sleep state is requested, ignore
 199                                 inhibitor locks. Applications can
 200                                 establish inhibitor locks to avoid
 201                                 that certain important operations
 202                                 (such as CD burning or suchlike) are
 203                                 interrupted by system shutdown or a
 204                                 sleep state. Any user may take these
 205                                 locks and privileged users may
 206                                 override these locks. If any locks are
 207                                 taken, shutdown and sleep state
 208                                 requests will normally fail
 209                                 (regardless if privileged or not) and
 210                                 list of active locks is
 211                                 printed. However if
 212                                 <option>--ignore-inhibitors</option>
 213                                 is specified the locks are ignored and
 214                                 not printed, and the operation
 215                                 attempted anyway, possibly requiring
 216                                 additional
 217                                 privileges.</para></listitem>
 218                         </varlistentry>
 219
 220                         <varlistentry>
 221                                 <term><option>-q</option></term>
 222                                 <term><option>--quiet</option></term>
 223
 224                                 <listitem><para>Suppress output to
 225                                 STDOUT in
 226                                 <command>snapshot</command>,
 227                                 <command>is-active</command>,
 228                                 <command>is-failed</command>,
 229                                 <command>enable</command> and
 230                                 <command>disable</command>.</para></listitem>
 231                         </varlistentry>
 232
 233                         <varlistentry>
 234                                 <term><option>--no-block</option></term>
 235
 236                                 <listitem><para>Do not synchronously wait for
 237                                 the requested operation to finish. If this is
 238                                 not specified the job will be verified,
 239                                 enqueued and <command>systemctl</command> will
 240                                 wait until it is completed. By passing this
 241                                 argument it is only verified and
 242                                 enqueued.</para></listitem>
 243                         </varlistentry>
 244
 245                         <varlistentry>
 246                                 <term><option>--no-legend</option></term>
 247
 248                                 <listitem><para>Do not print a legend, i.e.
 249                                 the column headers and the footer with hints.
 250                                 </para></listitem>
 251                         </varlistentry>
 252
 253                         <varlistentry>
 254                                 <term><option>--no-pager</option></term>
 255
 256                                 <listitem><para>Do not pipe output into a
 257                                 pager.</para></listitem>
 258                         </varlistentry>
 259
 260                         <varlistentry>
 261                                 <term><option>--system</option></term>
 262
 263                                 <listitem><para>Talk to the systemd
 264                                 system manager. (Default)</para></listitem>
 265                         </varlistentry>
 266
 267                         <varlistentry>
 268                                 <term><option>--user</option></term>
 269
 270                                 <listitem><para>Talk to the systemd
 271                                 manager of the calling user.</para></listitem>
 272                         </varlistentry>
 273
 274                         <varlistentry>
 275                                 <term><option>--order</option></term>
 276                                 <term><option>--require</option></term>
 277
 278                                 <listitem><para>When used in
 279                                 conjunction with the
 280                                 <command>dot</command> command (see
 281                                 below), selects which dependencies are
 282                                 shown in the dependency graph. If
 283                                 <option>--order</option> is passed
 284                                 only dependencies of type
 285                                 <varname>After=</varname> or
 286                                 <varname>Before=</varname> are
 287                                 shown. If <option>--require</option>
 288                                 is passed only dependencies of type
 289                                 <varname>Requires=</varname>,
 290                                 <varname>RequiresOverridable=</varname>,
 291                                 <varname>Requisite=</varname>,
 292                                 <varname>RequisiteOverridable=</varname>,
 293                                 <varname>Wants=</varname> and
 294                                 <varname>Conflicts=</varname> are
 295                                 shown. If neither is passed, shows
 296                                 dependencies of all these
 297                                 types.</para></listitem>
 298                         </varlistentry>
 299
 300                         <varlistentry>
 301                                 <term><option>--no-wall</option></term>
 302
 303                                 <listitem><para>Don't send wall
 304                                 message before
 305                                 halt, power-off, reboot.</para></listitem>
 306                         </varlistentry>
 307
 308                         <varlistentry>
 309                                 <term><option>--global</option></term>
 310
 311                                 <listitem><para>When used with
 312                                 <command>enable</command> and
 313                                 <command>disable</command>, operate on the
 314                                 global user configuration
 315                                 directory, thus enabling or disabling
 316                                 a unit file globally for all future
 317                                 logins of all users.</para></listitem>
 318                         </varlistentry>
 319
 320                         <varlistentry>
 321                                 <term><option>--no-reload</option></term>
 322
 323                                 <listitem><para>When used with
 324                                 <command>enable</command> and
 325                                 <command>disable</command>, do not
 326                                 implicitly reload daemon configuration
 327                                 after executing the
 328                                 changes.</para></listitem>
 329                         </varlistentry>
 330
 331                         <varlistentry>
 332                                 <term><option>--no-ask-password</option></term>
 333
 334                                 <listitem><para>When used with
 335                                 <command>start</command> and related
 336                                 commands, disables asking for
 337                                 passwords. Background services may
 338                                 require input of a password or
 339                                 passphrase string, for example to
 340                                 unlock system hard disks or
 341                                 cryptographic certificates. Unless
 342                                 this option is specified and the
 343                                 command is invoked from a terminal
 344                                 <command>systemctl</command> will
 345                                 query the user on the terminal for the
 346                                 necessary secrets. Use this option to
 347                                 switch this behavior off. In this case
 348                                 the password must be supplied by some
 349                                 other means (for example graphical
 350                                 password agents) or the service might
 351                                 fail. This also disables querying the
 352                                 user for authentication for privileged
 353                                 operations.</para></listitem>
 354                         </varlistentry>
 355
 356                         <varlistentry>
 357                                 <term><option>--kill-who=</option></term>
 358
 359                                 <listitem><para>When used with
 360                                 <command>kill</command>, choose which
 361                                 processes to kill. Must be one of
 362                                 <option>main</option>,
 363                                 <option>control</option> or
 364                                 <option>all</option> to select whether
 365                                 to kill only the main process of the
 366                                 unit, the control process or all
 367                                 processes of the unit. If omitted
 368                                 defaults to
 369                                 <option>all</option>.</para></listitem>
 370                         </varlistentry>
 371
 372                         <varlistentry>
 373                                 <term><option>-s</option></term>
 374                                 <term><option>--signal=</option></term>
 375
 376                                 <listitem><para>When used with
 377                                 <command>kill</command>, choose which
 378                                 signal to send to selected
 379                                 processes. Must be one of the well
 380                                 known signal specifiers such as
 381                                 SIGTERM, SIGINT or SIGSTOP. If
 382                                 omitted defaults to
 383                                 <option>SIGTERM</option>.</para></listitem>
 384                         </varlistentry>
 385
 386                         <varlistentry>
 387                                 <term><option>-f</option></term>
 388                                 <term><option>--force</option></term>
 389
 390                                 <listitem><para>When used with
 391                                 <command>enable</command>, overwrite any
 392                                 existing conflicting
 393                                 symlinks.</para></listitem>
 394
 395                                 <listitem><para>When used with
 396                                 <command>halt</command>,
 397                                 <command>poweroff</command>,
 398                                 <command>reboot</command> or
 399                                 <command>kexec</command> execute the
 400                                 selected operation without shutting
 401                                 down all units. However, all processes
 402                                 will be killed forcibly and all file
 403                                 systems are unmounted or remounted
 404                                 read-only. This is hence a drastic but
 405                                 relatively safe option to request an
 406                                 immediate reboot. If
 407                                 <option>--force</option> is specified
 408                                 twice for these operations, they will
 409                                 be executed immediately without
 410                                 terminating any processes or umounting
 411                                 any file systems. Warning: specifying
 412                                 <option>--force</option> twice with
 413                                 any of these operations might result
 414                                 in data loss.</para></listitem>
 415                         </varlistentry>
 416
 417                         <varlistentry>
 418                                 <term><option>--root=</option></term>
 419
 420                                 <listitem><para>When used with
 421                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and
 422                                 related commands), use alternative
 423                                 root path when looking for unit
 424                                 files.</para></listitem>
 425                         </varlistentry>
 426
 427                         <varlistentry>
 428                                 <term><option>--runtime</option></term>
 429
 430                                 <listitem><para>When used with
 431                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and related commands), make
 432                                 changes only temporarily, so that they
 433                                 are dropped on the next reboot. This
 434                                 will have the effect that changes are
 435                                 not made in subdirectories of
 436                                 <filename>/etc</filename> but in
 437                                 <filename>/run</filename>, with
 438                                 identical immediate effects, however,
 439                                 since the latter is lost on reboot,
 440                                 the changes are lost
 441                                 too.</para></listitem>
 442                         </varlistentry>
 443
 444                         <varlistentry>
 445                                 <term><option>-H</option></term>
 446                                 <term><option>--host</option></term>
 447
 448                                 <listitem><para>Execute operation
 449                                 remotely. Specify a hostname, or
 450                                 username and hostname separated by @,
 451                                 to connect to. This will use SSH to
 452                                 talk to the remote systemd
 453                                 instance.</para></listitem>
 454                         </varlistentry>
 455
 456                         <varlistentry>
 457                                 <term><option>-P</option></term>
 458                                 <term><option>--privileged</option></term>
 459
 460                                 <listitem><para>Acquire privileges via
 461                                 PolicyKit before executing the
 462                                 operation.</para></listitem>
 463                         </varlistentry>
 464
 465                         <varlistentry>
 466                                 <term><option>-n</option></term>
 467                                 <term><option>--lines=</option></term>
 468
 469                                 <listitem><para>When used with
 470                                 <command>status</command> controls the
 471                                 number of journal lines to show,
 472                                 counting from the most recent
 473                                 ones. Takes a positive integer
 474                                 argument. Defaults to
 475                                 10.</para></listitem>
 476                         </varlistentry>
 477
 478                         <varlistentry>
 479                                 <term><option>-o</option></term>
 480                                 <term><option>--output=</option></term>
 481
 482                                 <listitem><para>When used with
 483                                 <command>status</command> controls the
 484                                 formatting of the journal entries that
 485                                 are shown. For the available choices
 486                                 see
 487                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Defaults
 488                                 to
 489                                 <literal>short</literal>.</para></listitem>
 490                         </varlistentry>
 491
 492                 </variablelist>
 493
 494                 <para>The following commands are understood:</para>
 495
 496                 <variablelist>
 497                         <varlistentry>
 498                                 <term><command>list-units</command></term>
 499
 500                                 <listitem><para>List known units.</para></listitem>
 501                         </varlistentry>
 502                         <varlistentry>
 503                                 <term><command>start [NAME...]</command></term>
 504
 505                                 <listitem><para>Start (activate) one
 506                                 or more units specified on the command
 507                                 line.</para></listitem>
 508                         </varlistentry>
 509                         <varlistentry>
 510                                 <term><command>stop [NAME...]</command></term>
 511
 512                                 <listitem><para>Stop (deactivate) one
 513                                 or more units specified on the command
 514                                 line.</para></listitem>
 515                         </varlistentry>
 516                         <varlistentry>
 517                                 <term><command>reload [NAME...]</command></term>
 518
 519                                 <listitem><para>Asks all units listed
 520                                 on the command line to reload their
 521                                 configuration. Note that this will
 522                                 reload the service-specific
 523                                 configuration, not the unit
 524                                 configuration file of systemd. If you
 525                                 want systemd to reload the
 526                                 configuration file of a unit use the
 527                                 <command>daemon-reload</command>
 528                                 command. In other words: for the
 529                                 example case of Apache, this will
 530                                 reload Apache's
 531                                 <filename>httpd.conf</filename> in the
 532                                 web server, not the
 533                                 <filename>apache.service</filename>
 534                                 systemd unit file. </para>
 535
 536                                 <para>This command should not be
 537                                 confused with the
 538                                 <command>daemon-reload</command> or
 539                                 <command>load</command>
 540                                 commands.</para></listitem>
 541
 542                         </varlistentry>
 543                         <varlistentry>
 544                                 <term><command>restart [NAME...]</command></term>
 545
 546                                 <listitem><para>Restart one or more
 547                                 units specified on the command
 548                                 line. If the units are not running yet
 549                                 they will be
 550                                 started.</para></listitem>
 551                         </varlistentry>
 552                         <varlistentry>
 553                                 <term><command>try-restart [NAME...]</command></term>
 554
 555                                 <listitem><para>Restart one or more
 556                                 units specified on the command
 557                                 line if the units are running. Do
 558                                 nothing if units are not running.
 559                                 Note that for compatibility
 560                                 with Red Hat init scripts
 561                                 <command>condrestart</command> is
 562                                 equivalent to this command.</para></listitem>
 563                         </varlistentry>
 564                         <varlistentry>
 565                                 <term><command>reload-or-restart [NAME...]</command></term>
 566
 567                                 <listitem><para>Reload one or more
 568                                 units if they support it. If not,
 569                                 restart them instead. If the units
 570                                 are not running yet they will be
 571                                 started.</para></listitem>
 572                         </varlistentry>
 573                         <varlistentry>
 574                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 575
 576                                 <listitem><para>Reload one or more
 577                                 units if they support it. If not,
 578                                 restart them instead. Do nothing if
 579                                 the units are not running. Note that
 580                                 for compatibility with SysV init
 581                                 scripts
 582                                 <command>force-reload</command> is
 583                                 equivalent to this
 584                                 command.</para></listitem>
 585                         </varlistentry>
 586                         <varlistentry>
 587                                 <term><command>isolate [NAME]</command></term>
 588
 589                                 <listitem><para>Start the unit
 590                                 specified on the command line and its
 591                                 dependencies and stop all others.</para>
 592
 593                                 <para>This is similar to changing the
 594                                 runlevel in a traditional init system. The
 595                                 <command>isolate</command> command will
 596                                 immediately stop processes that are not
 597                                 enabled in the new unit, possibly including
 598                                 the graphical environment or terminal you
 599                                 are currently using.</para>
 600
 601                                 <para>Note that this works only on units
 602                                 where <option>AllowIsolate=</option> is
 603                                 enabled. See
 604                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 605                                 for details.</para></listitem>
 606                         </varlistentry>
 607                         <varlistentry>
 608                                 <term><command>kill [NAME...]</command></term>
 609
 610                                 <listitem><para>Send a signal to one
 611                                 or more processes of the unit. Use
 612                                 <option>--kill-who=</option> to select
 613                                 which process to kill. Use
 614                                 <option>--kill-mode=</option> to
 615                                 select the kill mode and
 616                                 <option>--signal=</option> to select
 617                                 the signal to send.</para></listitem>
 618                         </varlistentry>
 619                         <varlistentry>
 620                                 <term><command>is-active [NAME...]</command></term>
 621
 622                                 <listitem><para>Check whether any of
 623                                 the specified units are active
 624                                 (i.e. running). Returns an exit code
 625                                 0 if at least one is active, non-zero
 626                                 otherwise. Unless
 627                                 <option>--quiet</option> is specified
 628                                 this will also print the current unit
 629                                 state to STDOUT.</para></listitem>
 630                         </varlistentry>
 631                         <varlistentry>
 632                                 <term><command>is-failed [NAME...]</command></term>
 633
 634                                 <listitem><para>Check whether any of
 635                                 the specified units are failed.
 636                                 Returns an exit code
 637                                 0 if at least one is failed, non-zero
 638                                 otherwise. Unless
 639                                 <option>--quiet</option> is specified
 640                                 this will also print the current unit
 641                                 state to STDOUT.</para></listitem>
 642                         </varlistentry>
 643                         <varlistentry>
 644                                 <term><command>status [NAME...|PID...]</command></term>
 645
 646                                 <listitem><para>Show terse runtime
 647                                 status information about one or more
 648                                 units, followed by its most recent log
 649                                 data from the journal. This function
 650                                 is intended to generate human-readable
 651                                 output. If you are looking for
 652                                 computer-parsable output, use
 653                                 <command>show</command> instead. If a
 654                                 PID is passed information about the
 655                                 unit the process of the PID belongs to
 656                                 is shown.</para></listitem>
 657                         </varlistentry>
 658                         <varlistentry>
 659                                 <term><command>show [NAME...|JOB...]</command></term>
 660
 661                                 <listitem><para>Show properties of one
 662                                 or more units, jobs or the manager
 663                                 itself. If no argument is specified
 664                                 properties of the manager will be
 665                                 shown. If a unit name is specified
 666                                 properties of the unit is shown, and
 667                                 if a job id is specified properties of
 668                                 the job is shown. By default, empty
 669                                 properties are suppressed. Use
 670                                 <option>--all</option> to show those
 671                                 too. To select specific properties to
 672                                 show use
 673                                 <option>--property=</option>. This
 674                                 command is intended to be used
 675                                 whenever computer-parsable output is
 676                                 required. Use
 677                                 <command>status</command> if you are
 678                                 looking for formatted human-readable
 679                                 output.</para></listitem>
 680                         </varlistentry>
 681                         <varlistentry>
 682                                 <term><command>help [NAME...|PID...]</command></term>
 683
 684                                 <listitem><para>Show manual pages for
 685                                 one or more units, if available. If a
 686                                 PID is passed the manual pages for the
 687                                 unit the process of the PID belongs to
 688                                 is shown.</para></listitem>
 689                         </varlistentry>
 690                         <varlistentry>
 691                                 <term><command>reset-failed [NAME...]</command></term>
 692
 693                                 <listitem><para>Reset the
 694                                 '<literal>failed</literal>' state of the
 695                                 specified units, or if no unit name is
 696                                 passed of all units. When a unit fails
 697                                 in some way (i.e. process exiting with
 698                                 non-zero error code, terminating
 699                                 abnormally or timing out) it will
 700                                 automatically enter the
 701                                 '<literal>failed</literal>' state and
 702                                 its exit code and status is recorded
 703                                 for introspection by the administrator
 704                                 until the service is restarted or
 705                                 reset with this
 706                                 command.</para></listitem>
 707                         </varlistentry>
 708
 709                         <varlistentry>
 710                                 <term><command>list-unit-files</command></term>
 711
 712                                 <listitem><para>List installed unit files.
 713                                 </para></listitem>
 714                         </varlistentry>
 715
 716                         <varlistentry>
 717                                 <term><command>enable [NAME...]</command></term>
 718
 719                                 <listitem><para>Enable one or
 720                                 more unit files or unit file
 721                                 instances, as specified on the
 722                                 command line. This will create a
 723                                 number of symlinks as encoded in
 724                                 the <literal>[Install]</literal>
 725                                 sections of the unit files. After
 726                                 the symlinks have been created the
 727                                 systemd configuration is reloaded
 728                                 (in a way that is equivalent to
 729                                 <command>daemon-reload</command>)
 730                                 to ensure the changes are taken into
 731                                 account immediately. Note that this
 732                                 does not have the effect that any of
 733                                 the units enabled are also started at
 734                                 the same time.  If this is desired
 735                                 a separate <command>start</command>
 736                                 command must be invoked for the unit.
 737                                 Also note that in case of instance
 738                                 enablement, symlinks named same as
 739                                 instances are created in install
 740                                 location, however they all point to
 741                                 the same template unit file.</para>
 742
 743                                 <para>This command will
 744                                 print the actions executed. This
 745                                 output may be suppressed by passing
 746                                 <option>--quiet</option>.</para>
 747
 748                                 <para>Note that this operation creates
 749                                 only the suggested symlinks for the
 750                                 units. While this command is the
 751                                 recommended way to manipulate the unit
 752                                 configuration directory, the
 753                                 administrator is free to make
 754                                 additional changes manually, by
 755                                 placing or removing symlinks in the
 756                                 directory. This is particularly useful
 757                                 to create configurations that deviate
 758                                 from the suggested default
 759                                 installation. In this case the
 760                                 administrator must make sure to invoke
 761                                 <command>daemon-reload</command>
 762                                 manually as necessary, to ensure his
 763                                 changes are taken into account.</para>
 764
 765                                 <para>Enabling units should not be
 766                                 confused with starting (activating)
 767                                 units, as done by the
 768                                 <command>start</command>
 769                                 command. Enabling and starting units
 770                                 is orthogonal: units may be enabled
 771                                 without being started and started
 772                                 without being enabled. Enabling simply
 773                                 hooks the unit into various suggested
 774                                 places (for example, so that the unit
 775                                 is automatically started on boot or
 776                                 when a particular kind of hardware is
 777                                 plugged in). Starting actually spawns
 778                                 the daemon process (in case of service
 779                                 units), or binds the socket (in case
 780                                 of socket units), and so
 781                                 on.</para>
 782
 783                                 <para>Depending on whether
 784                                 <option>--system</option>,
 785                                 <option>--user</option> or
 786                                 <option>--global</option> is specified
 787                                 this enables the unit for the system,
 788                                 for the calling user only
 789                                 or for all future logins of all
 790                                 users. Note that in the latter case no
 791                                 systemd daemon configuration is
 792                                 reloaded.</para>
 793                                 </listitem>
 794                         </varlistentry>
 795
 796                         <varlistentry>
 797                                 <term><command>disable [NAME...]</command></term>
 798
 799                                 <listitem><para>Disables one or more
 800                                 units. This removes all symlinks to
 801                                 the specified unit files from the unit
 802                                 configuration directory, and hence
 803                                 undoes the changes made by
 804                                 <command>enable</command>. Note
 805                                 however that this removes
 806                                 all symlinks to the unit files
 807                                 (i.e. including manual additions), not
 808                                 just those actually created by
 809                                 <command>enable</command>. This call
 810                                 implicitly reloads the systemd daemon
 811                                 configuration after completing the
 812                                 disabling of the units. Note that this
 813                                 command does not implicitly stop the
 814                                 units that are being disabled. If this
 815                                 is desired an additional
 816                                 <command>stop</command> command should
 817                                 be executed afterwards.</para>
 818
 819                                 <para>This command will print the
 820                                 actions executed. This output may be
 821                                 suppressed by passing
 822                                 <option>--quiet</option>.</para>
 823                                 </listitem>
 824
 825                                 <para>This command honors
 826                                 <option>--system</option>,
 827                                 <option>--user</option>,
 828                                 <option>--global</option> in a similar
 829                                 way as
 830                                 <command>enable</command>.</para>
 831                         </varlistentry>
 832
 833                         <varlistentry>
 834                                 <term><command>is-enabled [NAME...]</command></term>
 835
 836                                 <listitem><para>Checks whether any of
 837                                 the specified unit files are enabled
 838                                 (as with
 839                                 <command>enable</command>). Returns an
 840                                 exit code of 0 if at least one is
 841                                 enabled, non-zero otherwise. Prints
 842                                 the current enable status. To suppress
 843                                 this output use
 844                                 <option>--quiet</option>.</para></listitem>
 845                         </varlistentry>
 846
 847                         <varlistentry>
 848                                 <term><command>reenable [NAME...]</command></term>
 849
 850                                 <listitem><para>Reenable one or more
 851                                 unit files, as specified on the
 852                                 command line. This is a combination of
 853                                 <command>disable</command> and
 854                                 <command>enable</command> and is
 855                                 useful to reset the symlinks a unit is
 856                                 enabled with to the defaults
 857                                 configured in the
 858                                 <literal>[Install]</literal> section
 859                                 of the unit file.</para>
 860                                 </listitem>
 861                         </varlistentry>
 862
 863                         <varlistentry>
 864                                 <term><command>preset [NAME...]</command></term>
 865
 866                                 <listitem><para>Reset one or more unit
 867                                 files, as specified on the command
 868                                 line, to the defaults configured in
 869                                 the preset policy files. This has the
 870                                 same effect as
 871                                 <command>disable</command> or
 872                                 <command>enable</command>, depending
 873                                 how the unit is listed in the preset
 874                                 files. For more information on preset
 875                                 policy format see
 876                                 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 877                                 more information on the concept of
 878                                 presets please consult the <ulink
 879                                 url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
 880                                 document.</para>
 881                                 </listitem>
 882                         </varlistentry>
 883
 884                         <varlistentry>
 885                                 <term><command>mask [NAME...]</command></term>
 886
 887                                 <listitem><para>Mask one or more unit
 888                                 files, as specified on the command
 889                                 line. This will link these units to
 890                                 <filename>/dev/null</filename>, making
 891                                 it impossible to start them. This is a stronger version
 892                                 of <command>disable</command>, since
 893                                 it prohibits all kinds of activation
 894                                 of the unit, including manual
 895                                 activation. Use this option with
 896                                 care.</para>
 897                                 </listitem>
 898                         </varlistentry>
 899
 900                         <varlistentry>
 901                                 <term><command>unmask [NAME...]</command></term>
 902
 903                                 <listitem><para>Unmask one or more
 904                                 unit files, as specified on the
 905                                 command line. This will undo the
 906                                 effect of
 907                                 <command>mask</command>.</para>
 908                                 </listitem>
 909                         </varlistentry>
 910
 911                         <varlistentry>
 912                                 <term><command>link [NAME...]</command></term>
 913
 914                                 <listitem><para>Link a unit file that
 915                                 is not in the unit file search paths
 916                                 into the unit file search path. This
 917                                 requires an absolute path to a unit
 918                                 file. The effect of this can be undone
 919                                 with <command>disable</command>. The
 920                                 effect of this command is that a unit
 921                                 file is available for
 922                                 <command>start</command> and other
 923                                 commands although it isn't installed
 924                                 directly in the unit search
 925                                 path.</para>
 926                                 </listitem>
 927                         </varlistentry>
 928
 929                         <varlistentry>
 930                                 <term><command>load [NAME...]</command></term>
 931
 932                                 <listitem><para>Load one or more units
 933                                 specified on the command line. This
 934                                 will simply load their configuration
 935                                 from disk, but not start them. To
 936                                 start them you need to use the
 937                                 <command>start</command> command which
 938                                 will implicitly load a unit that has
 939                                 not been loaded yet. Note that systemd
 940                                 garbage collects loaded units that are
 941                                 not active or referenced by an active
 942                                 unit. This means that units loaded
 943                                 this way will usually not stay loaded
 944                                 for long. Also note that this command
 945                                 cannot be used to reload unit
 946                                 configuration. Use the
 947                                 <command>daemon-reload</command>
 948                                 command for that. All in all, this
 949                                 command is of little use except for
 950                                 debugging.</para>
 951                                 <para>This command should not be
 952                                 confused with the
 953                                 <command>daemon-reload</command> or
 954                                 <command>reload</command>
 955                                 commands.</para></listitem>
 956                         </varlistentry>
 957                         <varlistentry>
 958                                 <term><command>list-jobs</command></term>
 959
 960                                 <listitem><para>List jobs that are in progress.</para></listitem>
 961                         </varlistentry>
 962                         <varlistentry>
 963                                 <term><command>cancel [JOB...]</command></term>
 964
 965                                 <listitem><para>Cancel one or more
 966                                 jobs specified on the command line by
 967                                 their numeric job
 968                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 969                         </varlistentry>
 970                         <varlistentry>
 971                                 <term><command>dump</command></term>
 972
 973                                 <listitem><para>Dump server
 974                                 status. This will output a (usually
 975                                 very long) human readable manager
 976                                 status dump. Its format is subject to
 977                                 change without notice and should not
 978                                 be parsed by
 979                                 applications.</para></listitem>
 980                         </varlistentry>
 981                         <varlistentry>
 982                                 <term><command>dot</command></term>
 983
 984                                 <listitem><para>Generate textual
 985                                 dependency graph description in dot
 986                                 format for further processing with the
 987                                 GraphViz
 988                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 989                                 tool. Use a command line like
 990                                 <command>systemctl dot | dot -Tsvg >
 991                                 systemd.svg</command> to generate a
 992                                 graphical dependency tree. Unless
 993                                 <option>--order</option> or
 994                                 <option>--require</option> is passed
 995                                 the generated graph will show both
 996                                 ordering and requirement
 997                                 dependencies.</para></listitem>
 998                         </varlistentry>
 999                         <varlistentry>
1000                                 <term><command>list-dependencies [NAME]</command></term>
1001
1002                                 <listitem><para> Shows required and
1003                                 wanted units of the specified unit. If
1004                                 no unit is specified
1005                                 <filename>default.target</filename> is
1006                                 implied. Target units are recursively
1007                                 expanded.  When <option>--all</option>
1008                                 is passed all other units aare
1009                                 recursively expanded as well.</para>
1010                                 </listitem>
1011                         </varlistentry>
1012                         <varlistentry>
1013                                 <term><command>snapshot [NAME]</command></term>
1014
1015                                 <listitem><para>Create a snapshot. If
1016                                 a snapshot name is specified, the new
1017                                 snapshot will be named after it. If
1018                                 none is specified an automatic
1019                                 snapshot name is generated. In either
1020                                 case, the snapshot name used is
1021                                 printed to STDOUT, unless
1022                                 <option>--quiet</option> is
1023                                 specified.</para>
1024
1025                                 <para>A snapshot refers to a saved
1026                                 state of the systemd manager. It is
1027                                 implemented itself as a unit that is
1028                                 generated dynamically with this
1029                                 command and has dependencies on all
1030                                 units active at the time. At a later
1031                                 time the user may return to this state
1032                                 by using the
1033                                 <command>isolate</command> command on
1034                                 the snapshot unit.</para></listitem>
1035
1036                                 <para>Snapshots are only useful for
1037                                 saving and restoring which units are
1038                                 running or are stopped, they do not
1039                                 save/restore any other
1040                                 state. Snapshots are dynamic and lost
1041                                 on reboot.</para>
1042                         </varlistentry>
1043                         <varlistentry>
1044                                 <term><command>delete [NAME...]</command></term>
1045
1046                                 <listitem><para>Remove a snapshot
1047                                 previously created with
1048                                 <command>snapshot</command>.</para></listitem>
1049                         </varlistentry>
1050                         <varlistentry>
1051                                 <term><command>daemon-reload</command></term>
1052
1053                                 <listitem><para>Reload systemd manager
1054                                 configuration. This will reload all
1055                                 unit files and recreate the entire
1056                                 dependency tree. While the daemon is
1057                                 reloaded, all sockets systemd listens
1058                                 on on behalf of user configuration will
1059                                 stay accessible.</para> <para>This
1060                                 command should not be confused with
1061                                 the <command>load</command> or
1062                                 <command>reload</command>
1063                                 commands.</para></listitem>
1064                         </varlistentry>
1065                         <varlistentry>
1066                                 <term><command>daemon-reexec</command></term>
1067
1068                                 <listitem><para>Reexecute the systemd
1069                                 manager. This will serialize the
1070                                 manager state, reexecute the process
1071                                 and deserialize the state again. This
1072                                 command is of little use except for
1073                                 debugging and package
1074                                 upgrades. Sometimes it might be
1075                                 helpful as a heavy-weight
1076                                 <command>daemon-reload</command>. While
1077                                 the daemon is reexecuted all sockets
1078                                 systemd listens on on behalf of user
1079                                 configuration will stay
1080                                 accessible.</para></listitem>
1081                         </varlistentry>
1082                         <varlistentry>
1083                                 <term><command>show-environment</command></term>
1084
1085                                 <listitem><para>Dump the systemd
1086                                 manager environment block. The
1087                                 environment block will be dumped in
1088                                 straight-forward form suitable for
1089                                 sourcing into a shell script. This
1090                                 environment block will be passed to
1091                                 all processes the manager
1092                                 spawns.</para></listitem>
1093                         </varlistentry>
1094                         <varlistentry>
1095                                 <term><command>set-environment [NAME=VALUE...]</command></term>
1096
1097                                 <listitem><para>Set one or more
1098                                 systemd manager environment variables,
1099                                 as specified on the command
1100                                 line.</para></listitem>
1101                         </varlistentry>
1102                         <varlistentry>
1103                                 <term><command>unset-environment [NAME...]</command></term>
1104
1105                                 <listitem><para>Unset one or more
1106                                 systemd manager environment
1107                                 variables. If only a variable name is
1108                                 specified it will be removed
1109                                 regardless of its value. If a variable
1110                                 and a value are specified the variable
1111                                 is only removed if it has the
1112                                 specified value.</para></listitem>
1113                         </varlistentry>
1114                         <varlistentry>
1115                                 <term><command>default</command></term>
1116
1117                                 <listitem><para>Enter default
1118                                 mode. This is mostly equivalent to
1119                                 <command>start
1120                                 default.target</command>.</para></listitem>
1121                         </varlistentry>
1122                         <varlistentry>
1123                                 <term><command>rescue</command></term>
1124
1125                                 <listitem><para>Enter rescue
1126                                 mode. This is mostly equivalent to
1127                                 <command>isolate
1128                                 rescue.target</command> but also
1129                                 prints a wall message to all
1130                                 users.</para></listitem>
1131                         </varlistentry>
1132                         <varlistentry>
1133                                 <term><command>emergency</command></term>
1134
1135                                 <listitem><para>Enter emergency
1136                                 mode. This is mostly equivalent to
1137                                 <command>isolate
1138                                 emergency.target</command> but also
1139                                 prints a wall message to all
1140                                 users.</para></listitem>
1141                         </varlistentry>
1142                         <varlistentry>
1143                                 <term><command>halt</command></term>
1144
1145                                 <listitem><para>Shut down and halt the
1146                                 system. This is mostly equivalent to
1147                                 <command>start halt.target</command>
1148                                 but also prints a wall message to all
1149                                 users.  If combined with
1150                                 <option>--force</option> shutdown of
1151                                 all running services is skipped,
1152                                 however all processes are killed and
1153                                 all file systems are unmounted or
1154                                 mounted read-only, immediately
1155                                 followed by the system halt.  If
1156                                 <option>--force</option> is specified
1157                                 twice the operation is immediately
1158                                 executed without terminating any
1159                                 processes or unmounting any file
1160                                 systems. This may result in data
1161                                 loss.</para></listitem>
1162                         </varlistentry>
1163                         <varlistentry>
1164                                 <term><command>poweroff</command></term>
1165
1166                                 <listitem><para>Shut down and
1167                                 power-off the system. This is mostly
1168                                 equivalent to <command>start
1169                                 poweroff.target</command> but also
1170                                 prints a wall message to all users. If
1171                                 combined with <option>--force</option>
1172                                 shutdown of all running services is
1173                                 skipped, however all processes are
1174                                 killed and all file systems are
1175                                 unmounted or mounted read-only,
1176                                 immediately followed by the powering
1177                                 off. If <option>--force</option> is
1178                                 specified twice the operation is
1179                                 immediately executed without
1180                                 terminating any processes or
1181                                 unmounting any file systems. This may
1182                                 result in data loss.</para></listitem>
1183                         </varlistentry>
1184                         <varlistentry>
1185                                 <term><command>reboot</command></term>
1186
1187                                 <listitem><para>Shut down and reboot
1188                                 the system. This is mostly equivalent
1189                                 to <command>start
1190                                 reboot.target</command> but also
1191                                 prints a wall message to all users. If
1192                                 combined with <option>--force</option>
1193                                 shutdown of all running services is
1194                                 skipped, however all processes are
1195                                 killed and all file systems are
1196                                 unmounted or mounted read-only,
1197                                 immediately followed by the reboot. If
1198                                 <option>--force</option> is specified
1199                                 twice the operation is immediately
1200                                 executed without terminating any
1201                                 processes or unmounting any file
1202                                 systems. This may result in data
1203                                 loss.</para></listitem>
1204                         </varlistentry>
1205                         <varlistentry>
1206                                 <term><command>kexec</command></term>
1207
1208                                 <listitem><para>Shut down and reboot
1209                                 the system via kexec. This is mostly
1210                                 equivalent to <command>start
1211                                 kexec.target</command> but also prints
1212                                 a wall message to all users. If
1213                                 combined with <option>--force</option>
1214                                 shutdown of all running services is
1215                                 skipped, however all processes are killed
1216                                 and all file systems are unmounted or
1217                                 mounted read-only, immediately
1218                                 followed by the
1219                                 reboot.</para></listitem>
1220                         </varlistentry>
1221                         <varlistentry>
1222                                 <term><command>exit</command></term>
1223
1224                                 <listitem><para>Ask the systemd
1225                                 manager to quit. This is only
1226                                 supported for user service managers
1227                                 (i.e. in conjunction with the
1228                                 <option>--user</option> option) and
1229                                 will fail otherwise.</para></listitem>
1230                         </varlistentry>
1231                         <varlistentry>
1232                                 <term><command>suspend</command></term>
1233
1234                                 <listitem><para>Suspend the
1235                                 system. This will trigger activation
1236                                 of the special
1237                                 <filename>suspend.target</filename>
1238                                 target.</para></listitem>
1239                         </varlistentry>
1240                         <varlistentry>
1241                                 <term><command>hibernate</command></term>
1242
1243                                 <listitem><para>Hibernate the
1244                                 system. This will trigger activation
1245                                 of the special
1246                                 <filename>hibernate.target</filename>
1247                                 target.</para></listitem>
1248                         </varlistentry>
1249                         <varlistentry>
1250                                 <term><command>hybrid-sleep</command></term>
1251
1252                                 <listitem><para>Hibernate and suspend
1253                                 the system. This will trigger
1254                                 activation of the special
1255                                 <filename>hybrid-sleep.target</filename>
1256                                 target.</para></listitem>
1257                         </varlistentry>
1258                         <varlistentry>
1259                                 <term><command>switch-root [ROOT] [INIT]</command></term>
1260
1261                                 <listitem><para>Switches to a
1262                                 different root directory and executes
1263                                 a new system manager process below
1264                                 it. This is intended for usage in
1265                                 initial RAM disks ("initrd"), and will
1266                                 transition from the initrd's system
1267                                 manager process (a.k.a "init" process)
1268                                 to the main system manager
1269                                 process. Takes two arguments: the
1270                                 directory to make the new root
1271                                 directory, and the path to the new
1272                                 system manager binary below it to
1273                                 execute as PID 1. If the latter is
1274                                 omitted or the empty string, a
1275                                 systemd binary will automatically be
1276                                 searched for and used as init. If the
1277                                 system manager path is omitted or
1278                                 equal the empty string the state of
1279                                 the initrd's system manager process is
1280                                 passed to the main system manager,
1281                                 which allows later introspection of the
1282                                 state of the services involved in the
1283                                 initrd boot.</para></listitem>
1284                         </varlistentry>
1285                 </variablelist>
1286
1287         </refsect1>
1288
1289         <refsect1>
1290                 <title>Exit status</title>
1291
1292                 <para>On success 0 is returned, a non-zero failure
1293                 code otherwise.</para>
1294         </refsect1>
1295
1296         <refsect1>
1297                 <title>Environment</title>
1298
1299                 <variablelist class='environment-variables'>
1300                         <varlistentry>
1301                                 <term><varname>$SYSTEMD_PAGER</varname></term>
1302                                 <listitem><para>Pager to use when
1303                                 <option>--no-pager</option> is not given;
1304                                 overrides <varname>$PAGER</varname>.  Setting
1305                                 this to an empty string or the value
1306                                 <literal>cat</literal> is equivalent to passing
1307                                 <option>--no-pager</option>.</para></listitem>
1308                         </varlistentry>
1309                 </variablelist>
1310         </refsect1>
1311
1312         <refsect1>
1313                 <title>See Also</title>
1314                 <para>
1315                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1316                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1317                         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1318                         <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1319                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1320                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1321                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1322                         <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1323                 </para>
1324         </refsect1>
1325
1326 </refentry>