man/systemctl.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   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
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  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
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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>--help</option></term>
  73                                 <term><option>-h</option></term>
  74
  75                                 <listitem><para>Prints a short help
  76                                 text and exits.</para></listitem>
  77                         </varlistentry>
  78
  79                         <varlistentry>
  80                                 <term><option>--version</option></term>
  81
  82                                 <listitem><para>Prints a short version
  83                                 string and exits.</para></listitem>
  84                         </varlistentry>
  85
  86                         <varlistentry>
  87                                 <term><option>--type=</option></term>
  88                                 <term><option>-t</option></term>
  89
  90                                 <listitem><para>When listing units,
  91                                 limit display to certain unit
  92                                 types. If not specified units of all
  93                                 types will be shown. The argument
  94                                 should be a unit type name such as
  95                                 <option>service</option>,
  96                                 <option>socket</option> and
  97                                 similar.</para></listitem>
  98                         </varlistentry>
  99
 100                         <varlistentry>
 101                                 <term><option>--property=</option></term>
 102                                 <term><option>-p</option></term>
 103
 104                                 <listitem><para>When showing
 105                                 unit/job/manager properties, limit
 106                                 display to certain properties as
 107                                 specified as argument. If not
 108                                 specified all set properties are
 109                                 shown. The argument should be a
 110                                 property name, such as
 111                                 <literal>MainPID</literal>. If
 112                                 specified more than once all
 113                                 properties with the specified names
 114                                 are shown.</para></listitem>
 115                         </varlistentry>
 116
 117                         <varlistentry>
 118                                 <term><option>--all</option></term>
 119                                 <term><option>-a</option></term>
 120
 121                                 <listitem><para>When listing units,
 122                                 show all units, regardless of their
 123                                 state, including inactive units. When
 124                                 showing unit/job/manager properties,
 125                                 show all properties regardless whether
 126                                 they are set or not.</para></listitem>
 127                         </varlistentry>
 128
 129                         <varlistentry>
 130                                 <term><option>--failed</option></term>
 131
 132                                 <listitem><para>When listing units,
 133                                 show only failed units. Do not confuse
 134                                 with
 135                                 <option>--fail</option>.</para></listitem>
 136                         </varlistentry>
 137
 138                         <varlistentry>
 139                                 <term><option>--full</option></term>
 140
 141                                 <listitem><para>Do not ellipsize unit
 142                                 names and truncate unit descriptions
 143                                 in the output of
 144                                 <command>list-units</command> and
 145                                 <command>list-jobs</command>.</para></listitem>
 146                         </varlistentry>
 147
 148                         <varlistentry>
 149                                 <term><option>--fail</option></term>
 150
 151                                 <listitem><para>If the requested
 152                                 operation conflicts with a pending
 153                                 unfinished job, fail the command. If
 154                                 this is not specified the requested
 155                                 operation will replace the pending job,
 156                                 if necessary. Do not confuse
 157                                 with
 158                                 <option>--failed</option>.</para></listitem>
 159                         </varlistentry>
 160
 161                         <varlistentry>
 162                                 <term><option>--ignore-dependencies</option></term>
 163
 164                                 <listitem><para>When enqueuing a new
 165                                 job ignore all its dependencies and
 166                                 execute it immediately. If passed no
 167                                 required units of the unit passed will
 168                                 be pulled in, and no ordering
 169                                 dependencies will be honoured. This is
 170                                 mostly a debugging and rescue tool for
 171                                 the administrator and should not be
 172                                 used by
 173                                 applications.</para></listitem>
 174                         </varlistentry>
 175
 176                         <varlistentry>
 177                                 <term><option>--quiet</option></term>
 178                                 <term><option>-q</option></term>
 179
 180                                 <listitem><para>Suppress output to
 181                                 STDOUT in
 182                                 <command>snapshot</command>,
 183                                 <command>is-active</command>,
 184                                 <command>enable</command> and
 185                                 <command>disable</command>.</para></listitem>
 186                         </varlistentry>
 187
 188                         <varlistentry>
 189                                 <term><option>--no-block</option></term>
 190
 191                                 <listitem><para>Do not synchronously wait for
 192                                 the requested operation to finish. If this is
 193                                 not specified the job will be verified,
 194                                 enqueued and <command>systemctl</command> will
 195                                 wait until it is completed. By passing this
 196                                 argument it is only verified and
 197                                 enqueued.</para></listitem>
 198                         </varlistentry>
 199
 200                         <varlistentry>
 201                                 <term><option>--no-legend</option></term>
 202
 203                                 <listitem><para>Do not print a legend, i.e.
 204                                 the column headers and the footer with hints.
 205                                 </para></listitem>
 206                         </varlistentry>
 207
 208                         <varlistentry>
 209                                 <term><option>--no-pager</option></term>
 210
 211                                 <listitem><para>Do not pipe output into a
 212                                 pager.</para></listitem>
 213                         </varlistentry>
 214
 215                         <varlistentry>
 216                                 <term><option>--system</option></term>
 217
 218                                 <listitem><para>Talk to the systemd
 219                                 system manager. (Default)</para></listitem>
 220                         </varlistentry>
 221
 222                         <varlistentry>
 223                                 <term><option>--user</option></term>
 224
 225                                 <listitem><para>Talk to the systemd
 226                                 manager of the calling user.</para></listitem>
 227                         </varlistentry>
 228
 229                         <varlistentry>
 230                                 <term><option>--order</option></term>
 231                                 <term><option>--require</option></term>
 232
 233                                 <listitem><para>When used in
 234                                 conjunction with the
 235                                 <command>dot</command> command (see
 236                                 below), selects which dependencies are
 237                                 shown in the dependency graph. If
 238                                 <option>--order</option> is passed
 239                                 only dependencies of type
 240                                 <varname>After=</varname> or
 241                                 <varname>Before=</varname> are
 242                                 shown. If <option>--require</option>
 243                                 is passed only dependencies of type
 244                                 <varname>Requires=</varname>,
 245                                 <varname>RequiresOverridable=</varname>,
 246                                 <varname>Requisite=</varname>,
 247                                 <varname>RequisiteOverridable=</varname>,
 248                                 <varname>Wants=</varname> and
 249                                 <varname>Conflicts=</varname> are
 250                                 shown. If neither is passed, shows
 251                                 dependencies of all these
 252                                 types.</para></listitem>
 253                         </varlistentry>
 254
 255                         <varlistentry>
 256                                 <term><option>--no-wall</option></term>
 257
 258                                 <listitem><para>Don't send wall
 259                                 message before
 260                                 halt, power-off, reboot.</para></listitem>
 261                         </varlistentry>
 262
 263                         <varlistentry>
 264                                 <term><option>--global</option></term>
 265
 266                                 <listitem><para>When used with
 267                                 <command>enable</command> and
 268                                 <command>disable</command>, operate on the
 269                                 global user configuration
 270                                 directory, thus enabling or disabling
 271                                 a unit file globally for all future
 272                                 logins of all users.</para></listitem>
 273                         </varlistentry>
 274
 275                         <varlistentry>
 276                                 <term><option>--no-reload</option></term>
 277
 278                                 <listitem><para>When used with
 279                                 <command>enable</command> and
 280                                 <command>disable</command>, do not
 281                                 implicitly reload daemon configuration
 282                                 after executing the
 283                                 changes.</para></listitem>
 284                         </varlistentry>
 285
 286                         <varlistentry>
 287                                 <term><option>--no-ask-password</option></term>
 288
 289                                 <listitem><para>When used with
 290                                 <command>start</command> and related
 291                                 commands, disables asking for
 292                                 passwords. Background services may
 293                                 require input of a password or
 294                                 passphrase string, for example to
 295                                 unlock system hard disks or
 296                                 cryptographic certificates. Unless
 297                                 this option is specified and the
 298                                 command is invoked from a terminal
 299                                 <command>systemctl</command> will
 300                                 query the user on the terminal for the
 301                                 necessary secrets. Use this option to
 302                                 switch this behavior off. In this case
 303                                 the password must be supplied by some
 304                                 other means (for example graphical
 305                                 password agents) or the service might
 306                                 fail. This also disables querying the
 307                                 user for authentication for privileged
 308                                 operations.</para></listitem>
 309                         </varlistentry>
 310
 311                         <varlistentry>
 312                                 <term><option>--kill-who=</option></term>
 313
 314                                 <listitem><para>When used with
 315                                 <command>kill</command>, choose which
 316                                 processes to kill. Must be one of
 317                                 <option>main</option>,
 318                                 <option>control</option> or
 319                                 <option>all</option> to select whether
 320                                 to kill only the main process of the
 321                                 unit, the control process or all
 322                                 processes of the unit. If omitted
 323                                 defaults to
 324                                 <option>all</option>.</para></listitem>
 325                         </varlistentry>
 326
 327                         <varlistentry>
 328                                 <term><option>--signal=</option></term>
 329                                 <term><option>-s</option></term>
 330
 331                                 <listitem><para>When used with
 332                                 <command>kill</command>, choose which
 333                                 signal to send to selected
 334                                 processes. Must be one of the well
 335                                 known signal specifiers such as
 336                                 SIGTERM, SIGINT or SIGSTOP. If
 337                                 omitted defaults to
 338                                 <option>SIGTERM</option>.</para></listitem>
 339                         </varlistentry>
 340
 341                         <varlistentry>
 342                                 <term><option>--force</option></term>
 343                                 <term><option>-f</option></term>
 344
 345                                 <listitem><para>When used with
 346                                 <command>enable</command>, overwrite any
 347                                 existing conflicting
 348                                 symlinks.</para></listitem>
 349
 350                                 <listitem><para>When used with
 351                                 <command>halt</command>,
 352                                 <command>poweroff</command>,
 353                                 <command>reboot</command> or
 354                                 <command>kexec</command> execute the
 355                                 selected operation without shutting
 356                                 down all units. However, all processes
 357                                 will be killed forcibly and all file
 358                                 systems are unmounted or remounted
 359                                 read-only. This is hence a drastic but
 360                                 relatively safe option to request an
 361                                 immediate reboot. If
 362                                 <option>--force</option> is specified
 363                                 twice for these operations, they will
 364                                 be executed immediately without
 365                                 terminating any processes or umounting
 366                                 any file systems. Warning: specifying
 367                                 <option>--force</option> twice with
 368                                 any of these operations might result
 369                                 in data loss.</para></listitem>
 370                         </varlistentry>
 371
 372                         <varlistentry>
 373                                 <term><option>--root=</option></term>
 374
 375                                 <listitem><para>When used with
 376                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and
 377                                 related commands), use alternative
 378                                 root path when looking for unit
 379                                 files.</para></listitem>
 380                         </varlistentry>
 381
 382                         <varlistentry>
 383                                 <term><option>--runtime</option></term>
 384
 385                                 <listitem><para>When used with
 386                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and related commands), make
 387                                 changes only temporarily, so that they
 388                                 are dropped on the next reboot. This
 389                                 will have the effect that changes are
 390                                 not made in subdirectories of
 391                                 <filename>/etc</filename> but in
 392                                 <filename>/run</filename>, with
 393                                 identical immediate effects, however,
 394                                 since the latter is lost on reboot,
 395                                 the changes are lost
 396                                 too.</para></listitem>
 397                         </varlistentry>
 398
 399                         <varlistentry>
 400                                 <term><option>-H</option></term>
 401                                 <term><option>--host</option></term>
 402
 403                                 <listitem><para>Execute operation
 404                                 remotely. Specify a hostname, or
 405                                 username and hostname separated by @,
 406                                 to connect to. This will use SSH to
 407                                 talk to the remote systemd
 408                                 instance.</para></listitem>
 409                         </varlistentry>
 410
 411                         <varlistentry>
 412                                 <term><option>-P</option></term>
 413                                 <term><option>--privileged</option></term>
 414
 415                                 <listitem><para>Acquire privileges via
 416                                 PolicyKit before executing the
 417                                 operation.</para></listitem>
 418                         </varlistentry>
 419
 420                         <varlistentry>
 421                                 <term><option>--lines=</option></term>
 422                                 <term><option>-n</option></term>
 423
 424                                 <listitem><para>When used with
 425                                 <command>status</command> controls the
 426                                 number of journal lines to show,
 427                                 counting from the most recent
 428                                 ones. Takes a positive integer
 429                                 argument. Defaults to
 430                                 10.</para></listitem>
 431                         </varlistentry>
 432
 433                         <varlistentry>
 434                                 <term><option>--follow</option></term>
 435                                 <term><option>-f</option></term>
 436
 437                                 <listitem><para>When used with
 438                                 <command>status</command> continously
 439                                 prints new journal entries as they are
 440                                 appended to the
 441                                 journal.</para></listitem>
 442                         </varlistentry>
 443
 444                         <varlistentry>
 445                                 <term><option>--output=</option></term>
 446                                 <term><option>-o</option></term>
 447
 448                                 <listitem><para>When used with
 449                                 <command>status</command> controls the
 450                                 formatting of the journal entries that
 451                                 are shown. For the available choices
 452                                 see
 453                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Defaults
 454                                 to
 455                                 <literal>short</literal>.</para></listitem>
 456                         </varlistentry>
 457
 458                 </variablelist>
 459
 460                 <para>The following commands are understood:</para>
 461
 462                 <variablelist>
 463                         <varlistentry>
 464                                 <term><command>list-units</command></term>
 465
 466                                 <listitem><para>List known units.</para></listitem>
 467                         </varlistentry>
 468                         <varlistentry>
 469                                 <term><command>start [NAME...]</command></term>
 470
 471                                 <listitem><para>Start (activate) one
 472                                 or more units specified on the command
 473                                 line.</para></listitem>
 474                         </varlistentry>
 475                         <varlistentry>
 476                                 <term><command>stop [NAME...]</command></term>
 477
 478                                 <listitem><para>Stop (deactivate) one
 479                                 or more units specified on the command
 480                                 line.</para></listitem>
 481                         </varlistentry>
 482                         <varlistentry>
 483                                 <term><command>reload [NAME...]</command></term>
 484
 485                                 <listitem><para>Asks all units listed
 486                                 on the command line to reload their
 487                                 configuration. Note that this will
 488                                 reload the service-specific
 489                                 configuration, not the unit
 490                                 configuration file of systemd. If you
 491                                 want systemd to reload the
 492                                 configuration file of a unit use the
 493                                 <command>daemon-reload</command>
 494                                 command. In other words: for the
 495                                 example case of Apache, this will
 496                                 reload Apache's
 497                                 <filename>httpd.conf</filename> in the
 498                                 web server, not the
 499                                 <filename>apache.service</filename>
 500                                 systemd unit file. </para>
 501
 502                                 <para>This command should not be
 503                                 confused with the
 504                                 <command>daemon-reload</command> or
 505                                 <command>load</command>
 506                                 commands.</para></listitem>
 507
 508                         </varlistentry>
 509                         <varlistentry>
 510                                 <term><command>restart [NAME...]</command></term>
 511
 512                                 <listitem><para>Restart one or more
 513                                 units specified on the command
 514                                 line. If the units are not running yet
 515                                 they will be
 516                                 started.</para></listitem>
 517                         </varlistentry>
 518                         <varlistentry>
 519                                 <term><command>try-restart [NAME...]</command></term>
 520
 521                                 <listitem><para>Restart one or more
 522                                 units specified on the command
 523                                 line if the units are running. Do
 524                                 nothing if units are not running.
 525                                 Note that for compatibility
 526                                 with Red Hat init scripts
 527                                 <command>condrestart</command> is
 528                                 equivalent to this command.</para></listitem>
 529                         </varlistentry>
 530                         <varlistentry>
 531                                 <term><command>reload-or-restart [NAME...]</command></term>
 532
 533                                 <listitem><para>Reload one or more
 534                                 units if they support it. If not,
 535                                 restart them instead. If the units
 536                                 are not running yet they will be
 537                                 started.</para></listitem>
 538                         </varlistentry>
 539                         <varlistentry>
 540                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 541
 542                                 <listitem><para>Reload one or more
 543                                 units if they support it. If not,
 544                                 restart them instead. Do nothing if
 545                                 the units are not running. Note that
 546                                 for compatibility with SysV init
 547                                 scripts
 548                                 <command>force-reload</command> is
 549                                 equivalent to this
 550                                 command.</para></listitem>
 551                         </varlistentry>
 552                         <varlistentry>
 553                                 <term><command>isolate [NAME]</command></term>
 554
 555                                 <listitem><para>Start the unit
 556                                 specified on the command line and its
 557                                 dependencies and stop all others.</para>
 558
 559                                 <para>This is similar to changing the
 560                                 runlevel in a traditional init system. The
 561                                 <command>isolate</command> command will
 562                                 immediately stop processes that are not
 563                                 enabled in the new unit, possibly including
 564                                 the graphical environment or terminal you
 565                                 are currently using.</para>
 566
 567                                 <para>Note that this works only on units
 568                                 where <option>AllowIsolate=</option> is
 569                                 enabled. See
 570                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 571                                 for details.</para></listitem>
 572                         </varlistentry>
 573                         <varlistentry>
 574                                 <term><command>kill [NAME...]</command></term>
 575
 576                                 <listitem><para>Send a signal to one
 577                                 or more processes of the unit. Use
 578                                 <option>--kill-who=</option> to select
 579                                 which process to kill. Use
 580                                 <option>--kill-mode=</option> to
 581                                 select the kill mode and
 582                                 <option>--signal=</option> to select
 583                                 the signal to send.</para></listitem>
 584                         </varlistentry>
 585                         <varlistentry>
 586                                 <term><command>is-active [NAME...]</command></term>
 587
 588                                 <listitem><para>Check whether any of
 589                                 the specified units are active
 590                                 (i.e. running). Returns an exit code
 591                                 0 if at least one is active, non-zero
 592                                 otherwise. Unless
 593                                 <option>--quiet</option> is specified
 594                                 this will also print the current unit
 595                                 state to STDOUT.</para></listitem>
 596                         </varlistentry>
 597                         <varlistentry>
 598                                 <term><command>status [NAME...|PID...]</command></term>
 599
 600                                 <listitem><para>Show terse runtime
 601                                 status information about one or more
 602                                 units, followed by its most recent log
 603                                 data from the journal. This function
 604                                 is intended to generate human-readable
 605                                 output. If you are looking for
 606                                 computer-parsable output, use
 607                                 <command>show</command> instead. If a
 608                                 PID is passed information about the
 609                                 unit the process of the PID belongs to
 610                                 is shown.</para></listitem>
 611                         </varlistentry>
 612                         <varlistentry>
 613                                 <term><command>show [NAME...|JOB...]</command></term>
 614
 615                                 <listitem><para>Show properties of one
 616                                 or more units, jobs or the manager
 617                                 itself. If no argument is specified
 618                                 properties of the manager will be
 619                                 shown. If a unit name is specified
 620                                 properties of the unit is shown, and
 621                                 if a job id is specified properties of
 622                                 the job is shown. By default, empty
 623                                 properties are suppressed. Use
 624                                 <option>--all</option> to show those
 625                                 too. To select specific properties to
 626                                 show use
 627                                 <option>--property=</option>. This
 628                                 command is intended to be used
 629                                 whenever computer-parsable output is
 630                                 required. Use
 631                                 <command>status</command> if you are
 632                                 looking for formatted human-readable
 633                                 output.</para></listitem>
 634                         </varlistentry>
 635
 636                         <varlistentry>
 637                                 <term><command>reset-failed [NAME...]</command></term>
 638
 639                                 <listitem><para>Reset the
 640                                 '<literal>failed</literal>' state of the
 641                                 specified units, or if no unit name is
 642                                 passed of all units. When a unit fails
 643                                 in some way (i.e. process exiting with
 644                                 non-zero error code, terminating
 645                                 abnormally or timing out) it will
 646                                 automatically enter the
 647                                 '<literal>failed</literal>' state and
 648                                 its exit code and status is recorded
 649                                 for introspection by the administrator
 650                                 until the service is restarted or
 651                                 reset with this
 652                                 command.</para></listitem>
 653                         </varlistentry>
 654
 655                         <varlistentry>
 656                                 <term><command>list-unit-files</command></term>
 657
 658                                 <listitem><para>List installed unit files.
 659                                 </para></listitem>
 660                         </varlistentry>
 661
 662                         <varlistentry>
 663                                 <term><command>enable [NAME...]</command></term>
 664
 665                                 <listitem><para>Enable one or more
 666                                 unit files, as specified on the
 667                                 command line. This will create a
 668                                 number of symlinks as encoded in the
 669                                 <literal>[Install]</literal> sections
 670                                 of the unit files. After the symlinks
 671                                 have been created the systemd
 672                                 configuration is reloaded (in a way
 673                                 that is equivalent to
 674                                 <command>daemon-reload</command>) to
 675                                 ensure the changes are taken into
 676                                 account immediately. Note that this
 677                                 does not have the effect that any of
 678                                 the units enabled are also started at
 679                                 the same time. If this is desired a
 680                                 separate <command>start</command>
 681                                 command must be invoked for the
 682                                 unit.</para>
 683
 684                                 <para>This command will
 685                                 print the actions executed. This
 686                                 output may be suppressed by passing
 687                                 <option>--quiet</option>.</para>
 688
 689                                 <para>Note that this operation creates
 690                                 only the suggested symlinks for the
 691                                 units. While this command is the
 692                                 recommended way to manipulate the unit
 693                                 configuration directory, the
 694                                 administrator is free to make
 695                                 additional changes manually, by
 696                                 placing or removing symlinks in the
 697                                 directory. This is particularly useful
 698                                 to create configurations that deviate
 699                                 from the suggested default
 700                                 installation. In this case the
 701                                 administrator must make sure to invoke
 702                                 <command>daemon-reload</command>
 703                                 manually as necessary, to ensure his
 704                                 changes are taken into account.</para>
 705
 706                                 <para>Enabling units should not be
 707                                 confused with starting (activating)
 708                                 units, as done by the
 709                                 <command>start</command>
 710                                 command. Enabling and starting units
 711                                 is orthogonal: units may be enabled
 712                                 without being started and started
 713                                 without being enabled. Enabling simply
 714                                 hooks the unit into various suggested
 715                                 places (for example, so that the unit
 716                                 is automatically started on boot or
 717                                 when a particular kind of hardware is
 718                                 plugged in). Starting actually spawns
 719                                 the daemon process (in case of service
 720                                 units), or binds the socket (in case
 721                                 of socket units), and so
 722                                 on.</para>
 723
 724                                 <para>Depending on whether
 725                                 <option>--system</option>,
 726                                 <option>--user</option> or
 727                                 <option>--global</option> is specified
 728                                 this enables the unit for the system,
 729                                 for the calling user only
 730                                 or for all future logins of all
 731                                 users. Note that in the latter case no
 732                                 systemd daemon configuration is
 733                                 reloaded.</para>
 734                                 </listitem>
 735                         </varlistentry>
 736
 737                         <varlistentry>
 738                                 <term><command>disable [NAME...]</command></term>
 739
 740                                 <listitem><para>Disables one or more
 741                                 units. This removes all symlinks to
 742                                 the specified unit files from the unit
 743                                 configuration directory, and hence
 744                                 undoes the changes made by
 745                                 <command>enable</command>. Note
 746                                 however that this removes
 747                                 all symlinks to the unit files
 748                                 (i.e. including manual additions), not
 749                                 just those actually created by
 750                                 <command>enable</command>. This call
 751                                 implicitly reloads the systemd daemon
 752                                 configuration after completing the
 753                                 disabling of the units. Note that this
 754                                 command does not implicitly stop the
 755                                 units that is being disabled. If this
 756                                 is desired an additional
 757                                 <command>stop</command>command should
 758                                 be executed afterwards.</para>
 759
 760                                 <para>This command will print the
 761                                 actions executed. This output may be
 762                                 suppressed by passing
 763                                 <option>--quiet</option>.</para>
 764                                 </listitem>
 765
 766                                 <para>This command honors
 767                                 <option>--system</option>,
 768                                 <option>--user</option>,
 769                                 <option>--global</option> in a similar
 770                                 way as
 771                                 <command>enable</command>.</para>
 772                         </varlistentry>
 773
 774                         <varlistentry>
 775                                 <term><command>is-enabled [NAME...]</command></term>
 776
 777                                 <listitem><para>Checks whether any of
 778                                 the specified unit files is enabled
 779                                 (as with
 780                                 <command>enable</command>). Returns an
 781                                 exit code of 0 if at least one is
 782                                 enabled, non-zero otherwise. Prints
 783                                 the current enable status. To suppress
 784                                 this output use
 785                                 <option>--quiet</option>.</para></listitem>
 786                         </varlistentry>
 787
 788                         <varlistentry>
 789                                 <term><command>reenable [NAME...]</command></term>
 790
 791                                 <listitem><para>Reenable one or more
 792                                 unit files, as specified on the
 793                                 command line. This is a combination of
 794                                 <command>disable</command> and
 795                                 <command>enable</command> and is
 796                                 useful to reset the symlinks a unit is
 797                                 enabled with to the defaults
 798                                 configured in the
 799                                 <literal>[Install]</literal> section
 800                                 of the unit file.</para>
 801                                 </listitem>
 802                         </varlistentry>
 803
 804                         <varlistentry>
 805                                 <term><command>preset [NAME...]</command></term>
 806
 807                                 <listitem><para>Reset one or more unit
 808                                 files, as specified on the command
 809                                 line, to the defaults configured in a
 810                                 preset file. This has the same effect
 811                                 as <command>disable</command> or
 812                                 <command>enable</command>, depending
 813                                 how the unit is listed in the preset
 814                                 files.</para>
 815                                 </listitem>
 816                         </varlistentry>
 817
 818                         <varlistentry>
 819                                 <term><command>mask [NAME...]</command></term>
 820
 821                                 <listitem><para>Mask one or more unit
 822                                 files, as specified on the command
 823                                 line. This will link these units to
 824                                 <filename>/dev/null</filename>, making
 825                                 it impossible to start them. This is a stronger version
 826                                 of <command>disable</command>, since
 827                                 it prohibits all kinds of activation
 828                                 of the unit, including manual
 829                                 activation. Use this option with
 830                                 care.</para>
 831                                 </listitem>
 832                         </varlistentry>
 833
 834                         <varlistentry>
 835                                 <term><command>unmask [NAME...]</command></term>
 836
 837                                 <listitem><para>Unmask one or more
 838                                 unit files, as specified on the
 839                                 command line. This will undo the
 840                                 effect of
 841                                 <command>mask</command>.</para>
 842                                 </listitem>
 843                         </varlistentry>
 844
 845                         <varlistentry>
 846                                 <term><command>link [NAME...]</command></term>
 847
 848                                 <listitem><para>Link a unit file that
 849                                 is not in the unit file search paths
 850                                 into the unit file search path. This
 851                                 requires an absolute path to a unit
 852                                 file. The effect of this can be undone
 853                                 with <command>disable</command>. The
 854                                 effect of this command is that a unit
 855                                 file is available for
 856                                 <command>start</command> and other
 857                                 commands although it isn't installed
 858                                 directly in the unit search
 859                                 path.</para>
 860                                 </listitem>
 861                         </varlistentry>
 862
 863                         <varlistentry>
 864                                 <term><command>load [NAME...]</command></term>
 865
 866                                 <listitem><para>Load one or more units
 867                                 specified on the command line. This
 868                                 will simply load their configuration
 869                                 from disk, but not start them. To
 870                                 start them you need to use the
 871                                 <command>start</command> command which
 872                                 will implicitly load a unit that has
 873                                 not been loaded yet. Note that systemd
 874                                 garbage collects loaded units that are
 875                                 not active or referenced by an active
 876                                 unit. This means that units loaded
 877                                 this way will usually not stay loaded
 878                                 for long. Also note that this command
 879                                 cannot be used to reload unit
 880                                 configuration. Use the
 881                                 <command>daemon-reload</command>
 882                                 command for that. All in all, this
 883                                 command is of little use except for
 884                                 debugging.</para>
 885                                 <para>This command should not be
 886                                 confused with the
 887                                 <command>daemon-reload</command> or
 888                                 <command>reload</command>
 889                                 commands.</para></listitem>
 890                         </varlistentry>
 891                         <varlistentry>
 892                                 <term><command>list-jobs</command></term>
 893
 894                                 <listitem><para>List jobs that are in progress.</para></listitem>
 895                         </varlistentry>
 896                         <varlistentry>
 897                                 <term><command>cancel [JOB...]</command></term>
 898
 899                                 <listitem><para>Cancel one or more
 900                                 jobs specified on the command line by
 901                                 their numeric job
 902                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 903                         </varlistentry>
 904                         <varlistentry>
 905                                 <term><command>dump</command></term>
 906
 907                                 <listitem><para>Dump server
 908                                 status. This will output a (usually
 909                                 very long) human readable manager
 910                                 status dump. Its format is subject to
 911                                 change without notice and should not
 912                                 be parsed by
 913                                 applications.</para></listitem>
 914                         </varlistentry>
 915                         <varlistentry>
 916                                 <term><command>dot</command></term>
 917
 918                                 <listitem><para>Generate textual
 919                                 dependency graph description in dot
 920                                 format for further processing with the
 921                                 GraphViz
 922                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 923                                 tool. Use a command line like
 924                                 <command>systemctl dot | dot -Tsvg >
 925                                 systemd.svg</command> to generate a
 926                                 graphical dependency tree. Unless
 927                                 <option>--order</option> or
 928                                 <option>--require</option> is passed
 929                                 the generated graph will show both
 930                                 ordering and requirement
 931                                 dependencies.</para></listitem>
 932                         </varlistentry>
 933                         <varlistentry>
 934                                 <term><command>snapshot [NAME]</command></term>
 935
 936                                 <listitem><para>Create a snapshot. If
 937                                 a snapshot name is specified, the new
 938                                 snapshot will be named after it. If
 939                                 none is specified an automatic
 940                                 snapshot name is generated. In either
 941                                 case, the snapshot name used is
 942                                 printed to STDOUT, unless
 943                                 <option>--quiet</option> is
 944                                 specified.</para>
 945
 946                                 <para>A snapshot refers to a saved
 947                                 state of the systemd manager. It is
 948                                 implemented itself as a unit that is
 949                                 generated dynamically with this
 950                                 command and has dependencies on all
 951                                 units active at the time. At a later
 952                                 time the user may return to this state
 953                                 by using the
 954                                 <command>isolate</command> command on
 955                                 the snapshot unit.</para></listitem>
 956
 957                                 <para>Snapshots are only useful for
 958                                 saving and restoring which units are
 959                                 running or are stopped, they do not
 960                                 save/restore any other
 961                                 state. Snapshots are dynamic and lost
 962                                 on reboot.</para>
 963                         </varlistentry>
 964                         <varlistentry>
 965                                 <term><command>delete [NAME...]</command></term>
 966
 967                                 <listitem><para>Remove a snapshot
 968                                 previously created with
 969                                 <command>snapshot</command>.</para></listitem>
 970                         </varlistentry>
 971                         <varlistentry>
 972                                 <term><command>daemon-reload</command></term>
 973
 974                                 <listitem><para>Reload systemd manager
 975                                 configuration. This will reload all
 976                                 unit files and recreate the entire
 977                                 dependency tree. While the daemon is
 978                                 reloaded, all sockets systemd listens
 979                                 on on behalf of user configuration will
 980                                 stay accessible.</para> <para>This
 981                                 command should not be confused with
 982                                 the <command>load</command> or
 983                                 <command>reload</command>
 984                                 commands.</para></listitem>
 985                         </varlistentry>
 986                         <varlistentry>
 987                                 <term><command>daemon-reexec</command></term>
 988
 989                                 <listitem><para>Reexecute the systemd
 990                                 manager. This will serialize the
 991                                 manager state, reexecute the process
 992                                 and deserialize the state again. This
 993                                 command is of little use except for
 994                                 debugging and package
 995                                 upgrades. Sometimes it might be
 996                                 helpful as a heavy-weight
 997                                 <command>daemon-reload</command>. While
 998                                 the daemon is reexecuted all sockets
 999                                 systemd listens on on behalf of user
1000                                 configuration will stay
1001                                 accessible.</para></listitem>
1002                         </varlistentry>
1003                         <varlistentry>
1004                                 <term><command>show-environment</command></term>
1005
1006                                 <listitem><para>Dump the systemd
1007                                 manager environment block. The
1008                                 environment block will be dumped in
1009                                 straight-forward form suitable for
1010                                 sourcing into a shell script. This
1011                                 environment block will be passed to
1012                                 all processes the manager
1013                                 spawns.</para></listitem>
1014                         </varlistentry>
1015                         <varlistentry>
1016                                 <term><command>set-environment [NAME=VALUE...]</command></term>
1017
1018                                 <listitem><para>Set one or more
1019                                 systemd manager environment variables,
1020                                 as specified on the command
1021                                 line.</para></listitem>
1022                         </varlistentry>
1023                         <varlistentry>
1024                                 <term><command>unset-environment [NAME...]</command></term>
1025
1026                                 <listitem><para>Unset one or more
1027                                 systemd manager environment
1028                                 variables. If only a variable name is
1029                                 specified it will be removed
1030                                 regardless of its value. If a variable
1031                                 and a value are specified the variable
1032                                 is only removed if it has the
1033                                 specified value.</para></listitem>
1034                         </varlistentry>
1035                         <varlistentry>
1036                                 <term><command>default</command></term>
1037
1038                                 <listitem><para>Enter default
1039                                 mode. This is mostly equivalent to
1040                                 <command>start
1041                                 default.target</command>.</para></listitem>
1042                         </varlistentry>
1043                         <varlistentry>
1044                                 <term><command>rescue</command></term>
1045
1046                                 <listitem><para>Enter rescue
1047                                 mode. This is mostly equivalent to
1048                                 <command>isolate
1049                                 rescue.target</command> but also
1050                                 prints a wall message to all
1051                                 users.</para></listitem>
1052                         </varlistentry>
1053                         <varlistentry>
1054                                 <term><command>emergency</command></term>
1055
1056                                 <listitem><para>Enter emergency
1057                                 mode. This is mostly equivalent to
1058                                 <command>isolate
1059                                 emergency.target</command> but also
1060                                 prints a wall message to all
1061                                 users.</para></listitem>
1062                         </varlistentry>
1063                         <varlistentry>
1064                                 <term><command>halt</command></term>
1065
1066                                 <listitem><para>Shut down and halt the
1067                                 system. This is mostly equivalent to
1068                                 <command>start halt.target</command>
1069                                 but also prints a wall message to all
1070                                 users.  If combined with
1071                                 <option>--force</option> shutdown of
1072                                 all running services is skipped,
1073                                 however all processes are killed and
1074                                 all file systems are unmounted or
1075                                 mounted read-only, immediately
1076                                 followed by the system halt.  If
1077                                 <option>--force</option> is specified
1078                                 twice the the operation is immediately
1079                                 executed without terminating any
1080                                 processes or unmounting any file
1081                                 systems. This may result in data
1082                                 loss.</para></listitem>
1083                         </varlistentry>
1084                         <varlistentry>
1085                                 <term><command>poweroff</command></term>
1086
1087                                 <listitem><para>Shut down and
1088                                 power-off the system. This is mostly
1089                                 equivalent to <command>start
1090                                 poweroff.target</command> but also
1091                                 prints a wall message to all users. If
1092                                 combined with <option>--force</option>
1093                                 shutdown of all running services is
1094                                 skipped, however all processes are
1095                                 killed and all file systems are
1096                                 unmounted or mounted read-only,
1097                                 immediately followed by the powering
1098                                 off. If <option>--force</option> is
1099                                 specified twice the the operation is
1100                                 immediately executed without
1101                                 terminating any processes or
1102                                 unmounting any file systems. This may
1103                                 result in data loss.</para></listitem>
1104                         </varlistentry>
1105                         <varlistentry>
1106                                 <term><command>reboot</command></term>
1107
1108                                 <listitem><para>Shut down and reboot
1109                                 the system. This is mostly equivalent
1110                                 to <command>start
1111                                 reboot.target</command> but also
1112                                 prints a wall message to all users. If
1113                                 combined with <option>--force</option>
1114                                 shutdown of all running services is
1115                                 skipped, however all processes are
1116                                 killed and all file systems are
1117                                 unmounted or mounted read-only,
1118                                 immediately followed by the reboot. If
1119                                 <option>--force</option> is specified
1120                                 twice the the operation is immediately
1121                                 executed without terminating any
1122                                 processes or unmounting any file
1123                                 systems. This may result in data
1124                                 loss.</para></listitem>
1125                         </varlistentry>
1126                         <varlistentry>
1127                                 <term><command>kexec</command></term>
1128
1129                                 <listitem><para>Shut down and reboot
1130                                 the system via kexec. This is mostly
1131                                 equivalent to <command>start
1132                                 kexec.target</command> but also prints
1133                                 a wall message to all users. If
1134                                 combined with <option>--force</option>
1135                                 shutdown of all running services is
1136                                 skipped, however all processes are killed
1137                                 and all file systems are unmounted or
1138                                 mounted read-only, immediately
1139                                 followed by the
1140                                 reboot.</para></listitem>
1141                         </varlistentry>
1142                         <varlistentry>
1143                                 <term><command>exit</command></term>
1144
1145                                 <listitem><para>Ask the systemd
1146                                 manager to quit. This is only
1147                                 supported for user service managers
1148                                 (i.e. in conjunction with the
1149                                 <option>--user</option> option) and
1150                                 will fail otherwise.</para></listitem>
1151                         </varlistentry>
1152                         <varlistentry>
1153                                 <term><command>suspend</command></term>
1154
1155                                 <listitem><para>Suspend the system.</para></listitem>
1156                         </varlistentry>
1157                         <varlistentry>
1158                                 <term><command>hibernate</command></term>
1159
1160                                 <listitem><para>Hibernate the system.</para></listitem>
1161                         </varlistentry>
1162                         <varlistentry>
1163                                 <term><command>switch-root [ROOT] [INIT]</command></term>
1164
1165                                 <listitem><para>Switches to a
1166                                 different root directory and executes
1167                                 a new system manager process below
1168                                 it. This is intended for usage in
1169                                 initial RAM disks ("initrd"), and will
1170                                 transition from the initrd's system
1171                                 manager process (a.k.a "init" process)
1172                                 to the main system manager
1173                                 process. Takes two arguments: the
1174                                 directory to make the new root
1175                                 directory, and the path to the new
1176                                 system manager binary below it to
1177                                 execute as PID 1. If the latter is
1178                                 ommitted or the empty string, a
1179                                 systemd binary will automatically be
1180                                 searched for and used as init. If the
1181                                 system manager path is ommitted or
1182                                 equal the empty string the state of
1183                                 the initrd's system manager process is
1184                                 passed to the main system manager,
1185                                 which allows later introspection of the
1186                                 state of the services involved in the
1187                                 initrd boot.</para></listitem>
1188                         </varlistentry>
1189                 </variablelist>
1190
1191         </refsect1>
1192
1193         <refsect1>
1194                 <title>Exit status</title>
1195
1196                 <para>On success 0 is returned, a non-zero failure
1197                 code otherwise.</para>
1198         </refsect1>
1199
1200         <refsect1>
1201                 <title>Environment</title>
1202
1203                 <variablelist>
1204                         <varlistentry>
1205                                 <term><varname>$SYSTEMD_PAGER</varname></term>
1206                                 <listitem><para>Pager to use when
1207                                 <option>--no-pager</option> is not given;
1208                                 overrides <varname>$PAGER</varname>.  Setting
1209                                 this to an empty string or the value
1210                                 <literal>cat</literal> is equivalent to passing
1211                                 <option>--no-pager</option>.</para></listitem>
1212                         </varlistentry>
1213                 </variablelist>
1214         </refsect1>
1215
1216         <refsect1>
1217                 <title>See Also</title>
1218                 <para>
1219                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1220                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1221                         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1222                         <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1223                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1224                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1225                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1226                 </para>
1227         </refsect1>
1228
1229 </refentry>