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
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 -->
  23
  24 <refentry id="systemctl">
  25
  26         <refentryinfo>
  27                 <title>systemctl</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>systemctl</refentrytitle>
  42                 <manvolnum>1</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemctl</refname>
  47                 <refpurpose>Control the systemd system and service manager</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <cmdsynopsis>
  52                         <command>systemctl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg> <arg choice="opt" rep="repeat">NAME</arg></command>
  53                 </cmdsynopsis>
  54         </refsynopsisdiv>
  55
  56         <refsect1>
  57                 <title>Description</title>
  58
  59                 <para><command>systemctl</command> may be used to
  60                 introspect and control the state of the
  61                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  62                 system and service manager.</para>
  63         </refsect1>
  64
  65         <refsect1>
  66                 <title>Options</title>
  67
  68                 <para>The following options are understood:</para>
  69
  70                 <variablelist>
  71                         <varlistentry>
  72                                 <term><option>--help</option></term>
  73                                 <term><option>-h</option></term>
  74
  75                                 <listitem><para>Prints a short help
  76                                 text and exits.</para></listitem>
  77                         </varlistentry>
  78
  79                         <varlistentry>
  80                                 <term><option>--version</option></term>
  81
  82                                 <listitem><para>Prints a short version
  83                                 string and exits.</para></listitem>
  84                         </varlistentry>
  85
  86                         <varlistentry>
  87                                 <term><option>--type=</option></term>
  88                                 <term><option>-t</option></term>
  89
  90                                 <listitem><para>The argument should
  91                                 be a unit type name such as
  92                                 <option>service</option> and
  93                                 <option>socket</option>,
  94                                 or a unit load state such as
  95                                 <option>loaded</option> and
  96                                 <option>masked</option>.
  97                                 </para>
  98
  99                                 <para>If the argument is a unit type,
 100                                 when listing units, limit display to
 101                                 certain unit types. If not specified
 102                                 units of all types will be shown.</para>
 103
 104                                 <para>If the argument is a unit load state,
 105                                 when listing units, limit display to
 106                                 certain unit types. If not specified
 107                                 units of in all load states will be
 108                                 shown.</para>
 109
 110                                 <para>As a special case, if the argument
 111                                 is <option>help</option>, a list of
 112                                 allowed values will be printed and the
 113                                 program will exit.</para>
 114                                 </listitem>
 115                         </varlistentry>
 116
 117                         <varlistentry>
 118                                 <term><option>--property=</option></term>
 119                                 <term><option>-p</option></term>
 120
 121                                 <listitem><para>When showing
 122                                 unit/job/manager properties, limit
 123                                 display to certain properties as
 124                                 specified as argument. If not
 125                                 specified all set properties are
 126                                 shown. The argument should be a
 127                                 property name, such as
 128                                 <literal>MainPID</literal>. If
 129                                 specified more than once all
 130                                 properties with the specified names
 131                                 are shown.</para></listitem>
 132                         </varlistentry>
 133
 134                         <varlistentry>
 135                                 <term><option>--all</option></term>
 136                                 <term><option>-a</option></term>
 137
 138                                 <listitem><para>When listing units,
 139                                 show all units, regardless of their
 140                                 state, including inactive units. When
 141                                 showing unit/job/manager properties,
 142                                 show all properties regardless whether
 143                                 they are set or not.</para></listitem>
 144                         </varlistentry>
 145
 146                         <varlistentry>
 147                                 <term><option>--failed</option></term>
 148
 149                                 <listitem><para>When listing units,
 150                                 show only failed units. Do not confuse
 151                                 with
 152                                 <option>--fail</option>.</para></listitem>
 153                         </varlistentry>
 154
 155                         <varlistentry>
 156                                 <term><option>--full</option></term>
 157
 158                                 <listitem><para>Do not ellipsize unit
 159                                 names and truncate unit descriptions
 160                                 in the output of
 161                                 <command>list-units</command> and
 162                                 <command>list-jobs</command>.</para></listitem>
 163                         </varlistentry>
 164
 165                         <varlistentry>
 166                                 <term><option>--fail</option></term>
 167
 168                                 <listitem><para>If the requested
 169                                 operation conflicts with a pending
 170                                 unfinished job, fail the command. If
 171                                 this is not specified the requested
 172                                 operation will replace the pending job,
 173                                 if necessary. Do not confuse
 174                                 with
 175                                 <option>--failed</option>.</para></listitem>
 176                         </varlistentry>
 177
 178                         <varlistentry>
 179                                 <term><option>--ignore-dependencies</option></term>
 180
 181                                 <listitem><para>When enqueuing a new
 182                                 job ignore all its dependencies and
 183                                 execute it immediately. If passed no
 184                                 required units of the unit passed will
 185                                 be pulled in, and no ordering
 186                                 dependencies will be honored. This is
 187                                 mostly a debugging and rescue tool for
 188                                 the administrator and should not be
 189                                 used by
 190                                 applications.</para></listitem>
 191                         </varlistentry>
 192
 193                         <varlistentry>
 194                                 <term><option>--quiet</option></term>
 195                                 <term><option>-q</option></term>
 196
 197                                 <listitem><para>Suppress output to
 198                                 STDOUT in
 199                                 <command>snapshot</command>,
 200                                 <command>is-active</command>,
 201                                 <command>enable</command> and
 202                                 <command>disable</command>.</para></listitem>
 203                         </varlistentry>
 204
 205                         <varlistentry>
 206                                 <term><option>--no-block</option></term>
 207
 208                                 <listitem><para>Do not synchronously wait for
 209                                 the requested operation to finish. If this is
 210                                 not specified the job will be verified,
 211                                 enqueued and <command>systemctl</command> will
 212                                 wait until it is completed. By passing this
 213                                 argument it is only verified and
 214                                 enqueued.</para></listitem>
 215                         </varlistentry>
 216
 217                         <varlistentry>
 218                                 <term><option>--no-legend</option></term>
 219
 220                                 <listitem><para>Do not print a legend, i.e.
 221                                 the column headers and the footer with hints.
 222                                 </para></listitem>
 223                         </varlistentry>
 224
 225                         <varlistentry>
 226                                 <term><option>--no-pager</option></term>
 227
 228                                 <listitem><para>Do not pipe output into a
 229                                 pager.</para></listitem>
 230                         </varlistentry>
 231
 232                         <varlistentry>
 233                                 <term><option>--system</option></term>
 234
 235                                 <listitem><para>Talk to the systemd
 236                                 system manager. (Default)</para></listitem>
 237                         </varlistentry>
 238
 239                         <varlistentry>
 240                                 <term><option>--user</option></term>
 241
 242                                 <listitem><para>Talk to the systemd
 243                                 manager of the calling user.</para></listitem>
 244                         </varlistentry>
 245
 246                         <varlistentry>
 247                                 <term><option>--order</option></term>
 248                                 <term><option>--require</option></term>
 249
 250                                 <listitem><para>When used in
 251                                 conjunction with the
 252                                 <command>dot</command> command (see
 253                                 below), selects which dependencies are
 254                                 shown in the dependency graph. If
 255                                 <option>--order</option> is passed
 256                                 only dependencies of type
 257                                 <varname>After=</varname> or
 258                                 <varname>Before=</varname> are
 259                                 shown. If <option>--require</option>
 260                                 is passed only dependencies of type
 261                                 <varname>Requires=</varname>,
 262                                 <varname>RequiresOverridable=</varname>,
 263                                 <varname>Requisite=</varname>,
 264                                 <varname>RequisiteOverridable=</varname>,
 265                                 <varname>Wants=</varname> and
 266                                 <varname>Conflicts=</varname> are
 267                                 shown. If neither is passed, shows
 268                                 dependencies of all these
 269                                 types.</para></listitem>
 270                         </varlistentry>
 271
 272                         <varlistentry>
 273                                 <term><option>--no-wall</option></term>
 274
 275                                 <listitem><para>Don't send wall
 276                                 message before
 277                                 halt, power-off, reboot.</para></listitem>
 278                         </varlistentry>
 279
 280                         <varlistentry>
 281                                 <term><option>--global</option></term>
 282
 283                                 <listitem><para>When used with
 284                                 <command>enable</command> and
 285                                 <command>disable</command>, operate on the
 286                                 global user configuration
 287                                 directory, thus enabling or disabling
 288                                 a unit file globally for all future
 289                                 logins of all users.</para></listitem>
 290                         </varlistentry>
 291
 292                         <varlistentry>
 293                                 <term><option>--no-reload</option></term>
 294
 295                                 <listitem><para>When used with
 296                                 <command>enable</command> and
 297                                 <command>disable</command>, do not
 298                                 implicitly reload daemon configuration
 299                                 after executing the
 300                                 changes.</para></listitem>
 301                         </varlistentry>
 302
 303                         <varlistentry>
 304                                 <term><option>--no-ask-password</option></term>
 305
 306                                 <listitem><para>When used with
 307                                 <command>start</command> and related
 308                                 commands, disables asking for
 309                                 passwords. Background services may
 310                                 require input of a password or
 311                                 passphrase string, for example to
 312                                 unlock system hard disks or
 313                                 cryptographic certificates. Unless
 314                                 this option is specified and the
 315                                 command is invoked from a terminal
 316                                 <command>systemctl</command> will
 317                                 query the user on the terminal for the
 318                                 necessary secrets. Use this option to
 319                                 switch this behavior off. In this case
 320                                 the password must be supplied by some
 321                                 other means (for example graphical
 322                                 password agents) or the service might
 323                                 fail. This also disables querying the
 324                                 user for authentication for privileged
 325                                 operations.</para></listitem>
 326                         </varlistentry>
 327
 328                         <varlistentry>
 329                                 <term><option>--kill-who=</option></term>
 330
 331                                 <listitem><para>When used with
 332                                 <command>kill</command>, choose which
 333                                 processes to kill. Must be one of
 334                                 <option>main</option>,
 335                                 <option>control</option> or
 336                                 <option>all</option> to select whether
 337                                 to kill only the main process of the
 338                                 unit, the control process or all
 339                                 processes of the unit. If omitted
 340                                 defaults to
 341                                 <option>all</option>.</para></listitem>
 342                         </varlistentry>
 343
 344                         <varlistentry>
 345                                 <term><option>--signal=</option></term>
 346                                 <term><option>-s</option></term>
 347
 348                                 <listitem><para>When used with
 349                                 <command>kill</command>, choose which
 350                                 signal to send to selected
 351                                 processes. Must be one of the well
 352                                 known signal specifiers such as
 353                                 SIGTERM, SIGINT or SIGSTOP. If
 354                                 omitted defaults to
 355                                 <option>SIGTERM</option>.</para></listitem>
 356                         </varlistentry>
 357
 358                         <varlistentry>
 359                                 <term><option>--force</option></term>
 360                                 <term><option>-f</option></term>
 361
 362                                 <listitem><para>When used with
 363                                 <command>enable</command>, overwrite any
 364                                 existing conflicting
 365                                 symlinks.</para></listitem>
 366
 367                                 <listitem><para>When used with
 368                                 <command>halt</command>,
 369                                 <command>poweroff</command>,
 370                                 <command>reboot</command> or
 371                                 <command>kexec</command> execute the
 372                                 selected operation without shutting
 373                                 down all units. However, all processes
 374                                 will be killed forcibly and all file
 375                                 systems are unmounted or remounted
 376                                 read-only. This is hence a drastic but
 377                                 relatively safe option to request an
 378                                 immediate reboot. If
 379                                 <option>--force</option> is specified
 380                                 twice for these operations, they will
 381                                 be executed immediately without
 382                                 terminating any processes or umounting
 383                                 any file systems. Warning: specifying
 384                                 <option>--force</option> twice with
 385                                 any of these operations might result
 386                                 in data loss.</para></listitem>
 387                         </varlistentry>
 388
 389                         <varlistentry>
 390                                 <term><option>--root=</option></term>
 391
 392                                 <listitem><para>When used with
 393                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and
 394                                 related commands), use alternative
 395                                 root path when looking for unit
 396                                 files.</para></listitem>
 397                         </varlistentry>
 398
 399                         <varlistentry>
 400                                 <term><option>--runtime</option></term>
 401
 402                                 <listitem><para>When used with
 403                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and related commands), make
 404                                 changes only temporarily, so that they
 405                                 are dropped on the next reboot. This
 406                                 will have the effect that changes are
 407                                 not made in subdirectories of
 408                                 <filename>/etc</filename> but in
 409                                 <filename>/run</filename>, with
 410                                 identical immediate effects, however,
 411                                 since the latter is lost on reboot,
 412                                 the changes are lost
 413                                 too.</para></listitem>
 414                         </varlistentry>
 415
 416                         <varlistentry>
 417                                 <term><option>-H</option></term>
 418                                 <term><option>--host</option></term>
 419
 420                                 <listitem><para>Execute operation
 421                                 remotely. Specify a hostname, or
 422                                 username and hostname separated by @,
 423                                 to connect to. This will use SSH to
 424                                 talk to the remote systemd
 425                                 instance.</para></listitem>
 426                         </varlistentry>
 427
 428                         <varlistentry>
 429                                 <term><option>-P</option></term>
 430                                 <term><option>--privileged</option></term>
 431
 432                                 <listitem><para>Acquire privileges via
 433                                 PolicyKit before executing the
 434                                 operation.</para></listitem>
 435                         </varlistentry>
 436
 437                         <varlistentry>
 438                                 <term><option>--lines=</option></term>
 439                                 <term><option>-n</option></term>
 440
 441                                 <listitem><para>When used with
 442                                 <command>status</command> controls the
 443                                 number of journal lines to show,
 444                                 counting from the most recent
 445                                 ones. Takes a positive integer
 446                                 argument. Defaults to
 447                                 10.</para></listitem>
 448                         </varlistentry>
 449
 450                         <varlistentry>
 451                                 <term><option>--output=</option></term>
 452                                 <term><option>-o</option></term>
 453
 454                                 <listitem><para>When used with
 455                                 <command>status</command> controls the
 456                                 formatting of the journal entries that
 457                                 are shown. For the available choices
 458                                 see
 459                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Defaults
 460                                 to
 461                                 <literal>short</literal>.</para></listitem>
 462                         </varlistentry>
 463
 464                 </variablelist>
 465
 466                 <para>The following commands are understood:</para>
 467
 468                 <variablelist>
 469                         <varlistentry>
 470                                 <term><command>list-units</command></term>
 471
 472                                 <listitem><para>List known units.</para></listitem>
 473                         </varlistentry>
 474                         <varlistentry>
 475                                 <term><command>start [NAME...]</command></term>
 476
 477                                 <listitem><para>Start (activate) one
 478                                 or more units specified on the command
 479                                 line.</para></listitem>
 480                         </varlistentry>
 481                         <varlistentry>
 482                                 <term><command>stop [NAME...]</command></term>
 483
 484                                 <listitem><para>Stop (deactivate) one
 485                                 or more units specified on the command
 486                                 line.</para></listitem>
 487                         </varlistentry>
 488                         <varlistentry>
 489                                 <term><command>reload [NAME...]</command></term>
 490
 491                                 <listitem><para>Asks all units listed
 492                                 on the command line to reload their
 493                                 configuration. Note that this will
 494                                 reload the service-specific
 495                                 configuration, not the unit
 496                                 configuration file of systemd. If you
 497                                 want systemd to reload the
 498                                 configuration file of a unit use the
 499                                 <command>daemon-reload</command>
 500                                 command. In other words: for the
 501                                 example case of Apache, this will
 502                                 reload Apache's
 503                                 <filename>httpd.conf</filename> in the
 504                                 web server, not the
 505                                 <filename>apache.service</filename>
 506                                 systemd unit file. </para>
 507
 508                                 <para>This command should not be
 509                                 confused with the
 510                                 <command>daemon-reload</command> or
 511                                 <command>load</command>
 512                                 commands.</para></listitem>
 513
 514                         </varlistentry>
 515                         <varlistentry>
 516                                 <term><command>restart [NAME...]</command></term>
 517
 518                                 <listitem><para>Restart one or more
 519                                 units specified on the command
 520                                 line. If the units are not running yet
 521                                 they will be
 522                                 started.</para></listitem>
 523                         </varlistentry>
 524                         <varlistentry>
 525                                 <term><command>try-restart [NAME...]</command></term>
 526
 527                                 <listitem><para>Restart one or more
 528                                 units specified on the command
 529                                 line if the units are running. Do
 530                                 nothing if units are not running.
 531                                 Note that for compatibility
 532                                 with Red Hat init scripts
 533                                 <command>condrestart</command> is
 534                                 equivalent to this command.</para></listitem>
 535                         </varlistentry>
 536                         <varlistentry>
 537                                 <term><command>reload-or-restart [NAME...]</command></term>
 538
 539                                 <listitem><para>Reload one or more
 540                                 units if they support it. If not,
 541                                 restart them instead. If the units
 542                                 are not running yet they will be
 543                                 started.</para></listitem>
 544                         </varlistentry>
 545                         <varlistentry>
 546                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 547
 548                                 <listitem><para>Reload one or more
 549                                 units if they support it. If not,
 550                                 restart them instead. Do nothing if
 551                                 the units are not running. Note that
 552                                 for compatibility with SysV init
 553                                 scripts
 554                                 <command>force-reload</command> is
 555                                 equivalent to this
 556                                 command.</para></listitem>
 557                         </varlistentry>
 558                         <varlistentry>
 559                                 <term><command>isolate [NAME]</command></term>
 560
 561                                 <listitem><para>Start the unit
 562                                 specified on the command line and its
 563                                 dependencies and stop all others.</para>
 564
 565                                 <para>This is similar to changing the
 566                                 runlevel in a traditional init system. The
 567                                 <command>isolate</command> command will
 568                                 immediately stop processes that are not
 569                                 enabled in the new unit, possibly including
 570                                 the graphical environment or terminal you
 571                                 are currently using.</para>
 572
 573                                 <para>Note that this works only on units
 574                                 where <option>AllowIsolate=</option> is
 575                                 enabled. See
 576                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 577                                 for details.</para></listitem>
 578                         </varlistentry>
 579                         <varlistentry>
 580                                 <term><command>kill [NAME...]</command></term>
 581
 582                                 <listitem><para>Send a signal to one
 583                                 or more processes of the unit. Use
 584                                 <option>--kill-who=</option> to select
 585                                 which process to kill. Use
 586                                 <option>--kill-mode=</option> to
 587                                 select the kill mode and
 588                                 <option>--signal=</option> to select
 589                                 the signal to send.</para></listitem>
 590                         </varlistentry>
 591                         <varlistentry>
 592                                 <term><command>is-active [NAME...]</command></term>
 593
 594                                 <listitem><para>Check whether any of
 595                                 the specified units are active
 596                                 (i.e. running). Returns an exit code
 597                                 0 if at least one is active, non-zero
 598                                 otherwise. Unless
 599                                 <option>--quiet</option> is specified
 600                                 this will also print the current unit
 601                                 state to STDOUT.</para></listitem>
 602                         </varlistentry>
 603                         <varlistentry>
 604                                 <term><command>status [NAME...|PID...]</command></term>
 605
 606                                 <listitem><para>Show terse runtime
 607                                 status information about one or more
 608                                 units, followed by its most recent log
 609                                 data from the journal. This function
 610                                 is intended to generate human-readable
 611                                 output. If you are looking for
 612                                 computer-parsable output, use
 613                                 <command>show</command> instead. If a
 614                                 PID is passed information about the
 615                                 unit the process of the PID belongs to
 616                                 is shown.</para></listitem>
 617                         </varlistentry>
 618                         <varlistentry>
 619                                 <term><command>show [NAME...|JOB...]</command></term>
 620
 621                                 <listitem><para>Show properties of one
 622                                 or more units, jobs or the manager
 623                                 itself. If no argument is specified
 624                                 properties of the manager will be
 625                                 shown. If a unit name is specified
 626                                 properties of the unit is shown, and
 627                                 if a job id is specified properties of
 628                                 the job is shown. By default, empty
 629                                 properties are suppressed. Use
 630                                 <option>--all</option> to show those
 631                                 too. To select specific properties to
 632                                 show use
 633                                 <option>--property=</option>. This
 634                                 command is intended to be used
 635                                 whenever computer-parsable output is
 636                                 required. Use
 637                                 <command>status</command> if you are
 638                                 looking for formatted human-readable
 639                                 output.</para></listitem>
 640                         </varlistentry>
 641                         <varlistentry>
 642                                 <term><command>help [NAME...|PID...]</command></term>
 643
 644                                 <listitem><para>Show manual pages for
 645                                 one or more units, if available. If a
 646                                 PID is passed the manual pages for the
 647                                 unit the process of the PID belongs to
 648                                 is shown.</para></listitem>
 649                         </varlistentry>
 650                         <varlistentry>
 651                                 <term><command>reset-failed [NAME...]</command></term>
 652
 653                                 <listitem><para>Reset the
 654                                 '<literal>failed</literal>' state of the
 655                                 specified units, or if no unit name is
 656                                 passed of all units. When a unit fails
 657                                 in some way (i.e. process exiting with
 658                                 non-zero error code, terminating
 659                                 abnormally or timing out) it will
 660                                 automatically enter the
 661                                 '<literal>failed</literal>' state and
 662                                 its exit code and status is recorded
 663                                 for introspection by the administrator
 664                                 until the service is restarted or
 665                                 reset with this
 666                                 command.</para></listitem>
 667                         </varlistentry>
 668
 669                         <varlistentry>
 670                                 <term><command>list-unit-files</command></term>
 671
 672                                 <listitem><para>List installed unit files.
 673                                 </para></listitem>
 674                         </varlistentry>
 675
 676                         <varlistentry>
 677                                 <term><command>enable [NAME...]</command></term>
 678
 679                                 <listitem><para>Enable one or
 680                                 more unit files or unit file
 681                                 instances, as specified on the
 682                                 command line. This will create a
 683                                 number of symlinks as encoded in
 684                                 the <literal>[Install]</literal>
 685                                 sections of the unit files. After
 686                                 the symlinks have been created the
 687                                 systemd configuration is reloaded
 688                                 (in a way that is equivalent to
 689                                 <command>daemon-reload</command>)
 690                                 to ensure the changes are taken into
 691                                 account immediately. Note that this
 692                                 does not have the effect that any of
 693                                 the units enabled are also started at
 694                                 the same time.  If this is desired
 695                                 a separate <command>start</command>
 696                                 command must be invoked for the unit.
 697                                 Also note that in case of instance
 698                                 enablement, symlinks named same as
 699                                 instances are created in install
 700                                 location, however they all point to
 701                                 the same template unit file.</para>
 702
 703                                 <para>This command will
 704                                 print the actions executed. This
 705                                 output may be suppressed by passing
 706                                 <option>--quiet</option>.</para>
 707
 708                                 <para>Note that this operation creates
 709                                 only the suggested symlinks for the
 710                                 units. While this command is the
 711                                 recommended way to manipulate the unit
 712                                 configuration directory, the
 713                                 administrator is free to make
 714                                 additional changes manually, by
 715                                 placing or removing symlinks in the
 716                                 directory. This is particularly useful
 717                                 to create configurations that deviate
 718                                 from the suggested default
 719                                 installation. In this case the
 720                                 administrator must make sure to invoke
 721                                 <command>daemon-reload</command>
 722                                 manually as necessary, to ensure his
 723                                 changes are taken into account.</para>
 724
 725                                 <para>Enabling units should not be
 726                                 confused with starting (activating)
 727                                 units, as done by the
 728                                 <command>start</command>
 729                                 command. Enabling and starting units
 730                                 is orthogonal: units may be enabled
 731                                 without being started and started
 732                                 without being enabled. Enabling simply
 733                                 hooks the unit into various suggested
 734                                 places (for example, so that the unit
 735                                 is automatically started on boot or
 736                                 when a particular kind of hardware is
 737                                 plugged in). Starting actually spawns
 738                                 the daemon process (in case of service
 739                                 units), or binds the socket (in case
 740                                 of socket units), and so
 741                                 on.</para>
 742
 743                                 <para>Depending on whether
 744                                 <option>--system</option>,
 745                                 <option>--user</option> or
 746                                 <option>--global</option> is specified
 747                                 this enables the unit for the system,
 748                                 for the calling user only
 749                                 or for all future logins of all
 750                                 users. Note that in the latter case no
 751                                 systemd daemon configuration is
 752                                 reloaded.</para>
 753                                 </listitem>
 754                         </varlistentry>
 755
 756                         <varlistentry>
 757                                 <term><command>disable [NAME...]</command></term>
 758
 759                                 <listitem><para>Disables one or more
 760                                 units. This removes all symlinks to
 761                                 the specified unit files from the unit
 762                                 configuration directory, and hence
 763                                 undoes the changes made by
 764                                 <command>enable</command>. Note
 765                                 however that this removes
 766                                 all symlinks to the unit files
 767                                 (i.e. including manual additions), not
 768                                 just those actually created by
 769                                 <command>enable</command>. This call
 770                                 implicitly reloads the systemd daemon
 771                                 configuration after completing the
 772                                 disabling of the units. Note that this
 773                                 command does not implicitly stop the
 774                                 units that are being disabled. If this
 775                                 is desired an additional
 776                                 <command>stop</command> command should
 777                                 be executed afterwards.</para>
 778
 779                                 <para>This command will print the
 780                                 actions executed. This output may be
 781                                 suppressed by passing
 782                                 <option>--quiet</option>.</para>
 783                                 </listitem>
 784
 785                                 <para>This command honors
 786                                 <option>--system</option>,
 787                                 <option>--user</option>,
 788                                 <option>--global</option> in a similar
 789                                 way as
 790                                 <command>enable</command>.</para>
 791                         </varlistentry>
 792
 793                         <varlistentry>
 794                                 <term><command>is-enabled [NAME...]</command></term>
 795
 796                                 <listitem><para>Checks whether any of
 797                                 the specified unit files are enabled
 798                                 (as with
 799                                 <command>enable</command>). Returns an
 800                                 exit code of 0 if at least one is
 801                                 enabled, non-zero otherwise. Prints
 802                                 the current enable status. To suppress
 803                                 this output use
 804                                 <option>--quiet</option>.</para></listitem>
 805                         </varlistentry>
 806
 807                         <varlistentry>
 808                                 <term><command>reenable [NAME...]</command></term>
 809
 810                                 <listitem><para>Reenable one or more
 811                                 unit files, as specified on the
 812                                 command line. This is a combination of
 813                                 <command>disable</command> and
 814                                 <command>enable</command> and is
 815                                 useful to reset the symlinks a unit is
 816                                 enabled with to the defaults
 817                                 configured in the
 818                                 <literal>[Install]</literal> section
 819                                 of the unit file.</para>
 820                                 </listitem>
 821                         </varlistentry>
 822
 823                         <varlistentry>
 824                                 <term><command>preset [NAME...]</command></term>
 825
 826                                 <listitem><para>Reset one or more unit
 827                                 files, as specified on the command
 828                                 line, to the defaults configured in
 829                                 the preset policy files. This has the
 830                                 same effect as
 831                                 <command>disable</command> or
 832                                 <command>enable</command>, depending
 833                                 how the unit is listed in the preset
 834                                 files. For more information on preset
 835                                 policy format see
 836                                 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 837                                 more information on the concept of
 838                                 presets please consult the <ulink
 839                                 url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
 840                                 document.</para>
 841                                 </listitem>
 842                         </varlistentry>
 843
 844                         <varlistentry>
 845                                 <term><command>mask [NAME...]</command></term>
 846
 847                                 <listitem><para>Mask one or more unit
 848                                 files, as specified on the command
 849                                 line. This will link these units to
 850                                 <filename>/dev/null</filename>, making
 851                                 it impossible to start them. This is a stronger version
 852                                 of <command>disable</command>, since
 853                                 it prohibits all kinds of activation
 854                                 of the unit, including manual
 855                                 activation. Use this option with
 856                                 care.</para>
 857                                 </listitem>
 858                         </varlistentry>
 859
 860                         <varlistentry>
 861                                 <term><command>unmask [NAME...]</command></term>
 862
 863                                 <listitem><para>Unmask one or more
 864                                 unit files, as specified on the
 865                                 command line. This will undo the
 866                                 effect of
 867                                 <command>mask</command>.</para>
 868                                 </listitem>
 869                         </varlistentry>
 870
 871                         <varlistentry>
 872                                 <term><command>link [NAME...]</command></term>
 873
 874                                 <listitem><para>Link a unit file that
 875                                 is not in the unit file search paths
 876                                 into the unit file search path. This
 877                                 requires an absolute path to a unit
 878                                 file. The effect of this can be undone
 879                                 with <command>disable</command>. The
 880                                 effect of this command is that a unit
 881                                 file is available for
 882                                 <command>start</command> and other
 883                                 commands although it isn't installed
 884                                 directly in the unit search
 885                                 path.</para>
 886                                 </listitem>
 887                         </varlistentry>
 888
 889                         <varlistentry>
 890                                 <term><command>load [NAME...]</command></term>
 891
 892                                 <listitem><para>Load one or more units
 893                                 specified on the command line. This
 894                                 will simply load their configuration
 895                                 from disk, but not start them. To
 896                                 start them you need to use the
 897                                 <command>start</command> command which
 898                                 will implicitly load a unit that has
 899                                 not been loaded yet. Note that systemd
 900                                 garbage collects loaded units that are
 901                                 not active or referenced by an active
 902                                 unit. This means that units loaded
 903                                 this way will usually not stay loaded
 904                                 for long. Also note that this command
 905                                 cannot be used to reload unit
 906                                 configuration. Use the
 907                                 <command>daemon-reload</command>
 908                                 command for that. All in all, this
 909                                 command is of little use except for
 910                                 debugging.</para>
 911                                 <para>This command should not be
 912                                 confused with the
 913                                 <command>daemon-reload</command> or
 914                                 <command>reload</command>
 915                                 commands.</para></listitem>
 916                         </varlistentry>
 917                         <varlistentry>
 918                                 <term><command>list-jobs</command></term>
 919
 920                                 <listitem><para>List jobs that are in progress.</para></listitem>
 921                         </varlistentry>
 922                         <varlistentry>
 923                                 <term><command>cancel [JOB...]</command></term>
 924
 925                                 <listitem><para>Cancel one or more
 926                                 jobs specified on the command line by
 927                                 their numeric job
 928                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 929                         </varlistentry>
 930                         <varlistentry>
 931                                 <term><command>dump</command></term>
 932
 933                                 <listitem><para>Dump server
 934                                 status. This will output a (usually
 935                                 very long) human readable manager
 936                                 status dump. Its format is subject to
 937                                 change without notice and should not
 938                                 be parsed by
 939                                 applications.</para></listitem>
 940                         </varlistentry>
 941                         <varlistentry>
 942                                 <term><command>dot</command></term>
 943
 944                                 <listitem><para>Generate textual
 945                                 dependency graph description in dot
 946                                 format for further processing with the
 947                                 GraphViz
 948                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 949                                 tool. Use a command line like
 950                                 <command>systemctl dot | dot -Tsvg >
 951                                 systemd.svg</command> to generate a
 952                                 graphical dependency tree. Unless
 953                                 <option>--order</option> or
 954                                 <option>--require</option> is passed
 955                                 the generated graph will show both
 956                                 ordering and requirement
 957                                 dependencies.</para></listitem>
 958                         </varlistentry>
 959                         <varlistentry>
 960                                 <term><command>snapshot [NAME]</command></term>
 961
 962                                 <listitem><para>Create a snapshot. If
 963                                 a snapshot name is specified, the new
 964                                 snapshot will be named after it. If
 965                                 none is specified an automatic
 966                                 snapshot name is generated. In either
 967                                 case, the snapshot name used is
 968                                 printed to STDOUT, unless
 969                                 <option>--quiet</option> is
 970                                 specified.</para>
 971
 972                                 <para>A snapshot refers to a saved
 973                                 state of the systemd manager. It is
 974                                 implemented itself as a unit that is
 975                                 generated dynamically with this
 976                                 command and has dependencies on all
 977                                 units active at the time. At a later
 978                                 time the user may return to this state
 979                                 by using the
 980                                 <command>isolate</command> command on
 981                                 the snapshot unit.</para></listitem>
 982
 983                                 <para>Snapshots are only useful for
 984                                 saving and restoring which units are
 985                                 running or are stopped, they do not
 986                                 save/restore any other
 987                                 state. Snapshots are dynamic and lost
 988                                 on reboot.</para>
 989                         </varlistentry>
 990                         <varlistentry>
 991                                 <term><command>delete [NAME...]</command></term>
 992
 993                                 <listitem><para>Remove a snapshot
 994                                 previously created with
 995                                 <command>snapshot</command>.</para></listitem>
 996                         </varlistentry>
 997                         <varlistentry>
 998                                 <term><command>daemon-reload</command></term>
 999
1000                                 <listitem><para>Reload systemd manager
1001                                 configuration. This will reload all
1002                                 unit files and recreate the entire
1003                                 dependency tree. While the daemon is
1004                                 reloaded, all sockets systemd listens
1005                                 on on behalf of user configuration will
1006                                 stay accessible.</para> <para>This
1007                                 command should not be confused with
1008                                 the <command>load</command> or
1009                                 <command>reload</command>
1010                                 commands.</para></listitem>
1011                         </varlistentry>
1012                         <varlistentry>
1013                                 <term><command>daemon-reexec</command></term>
1014
1015                                 <listitem><para>Reexecute the systemd
1016                                 manager. This will serialize the
1017                                 manager state, reexecute the process
1018                                 and deserialize the state again. This
1019                                 command is of little use except for
1020                                 debugging and package
1021                                 upgrades. Sometimes it might be
1022                                 helpful as a heavy-weight
1023                                 <command>daemon-reload</command>. While
1024                                 the daemon is reexecuted all sockets
1025                                 systemd listens on on behalf of user
1026                                 configuration will stay
1027                                 accessible.</para></listitem>
1028                         </varlistentry>
1029                         <varlistentry>
1030                                 <term><command>show-environment</command></term>
1031
1032                                 <listitem><para>Dump the systemd
1033                                 manager environment block. The
1034                                 environment block will be dumped in
1035                                 straight-forward form suitable for
1036                                 sourcing into a shell script. This
1037                                 environment block will be passed to
1038                                 all processes the manager
1039                                 spawns.</para></listitem>
1040                         </varlistentry>
1041                         <varlistentry>
1042                                 <term><command>set-environment [NAME=VALUE...]</command></term>
1043
1044                                 <listitem><para>Set one or more
1045                                 systemd manager environment variables,
1046                                 as specified on the command
1047                                 line.</para></listitem>
1048                         </varlistentry>
1049                         <varlistentry>
1050                                 <term><command>unset-environment [NAME...]</command></term>
1051
1052                                 <listitem><para>Unset one or more
1053                                 systemd manager environment
1054                                 variables. If only a variable name is
1055                                 specified it will be removed
1056                                 regardless of its value. If a variable
1057                                 and a value are specified the variable
1058                                 is only removed if it has the
1059                                 specified value.</para></listitem>
1060                         </varlistentry>
1061                         <varlistentry>
1062                                 <term><command>default</command></term>
1063
1064                                 <listitem><para>Enter default
1065                                 mode. This is mostly equivalent to
1066                                 <command>start
1067                                 default.target</command>.</para></listitem>
1068                         </varlistentry>
1069                         <varlistentry>
1070                                 <term><command>rescue</command></term>
1071
1072                                 <listitem><para>Enter rescue
1073                                 mode. This is mostly equivalent to
1074                                 <command>isolate
1075                                 rescue.target</command> but also
1076                                 prints a wall message to all
1077                                 users.</para></listitem>
1078                         </varlistentry>
1079                         <varlistentry>
1080                                 <term><command>emergency</command></term>
1081
1082                                 <listitem><para>Enter emergency
1083                                 mode. This is mostly equivalent to
1084                                 <command>isolate
1085                                 emergency.target</command> but also
1086                                 prints a wall message to all
1087                                 users.</para></listitem>
1088                         </varlistentry>
1089                         <varlistentry>
1090                                 <term><command>halt</command></term>
1091
1092                                 <listitem><para>Shut down and halt the
1093                                 system. This is mostly equivalent to
1094                                 <command>start halt.target</command>
1095                                 but also prints a wall message to all
1096                                 users.  If combined with
1097                                 <option>--force</option> shutdown of
1098                                 all running services is skipped,
1099                                 however all processes are killed and
1100                                 all file systems are unmounted or
1101                                 mounted read-only, immediately
1102                                 followed by the system halt.  If
1103                                 <option>--force</option> is specified
1104                                 twice the operation is immediately
1105                                 executed without terminating any
1106                                 processes or unmounting any file
1107                                 systems. This may result in data
1108                                 loss.</para></listitem>
1109                         </varlistentry>
1110                         <varlistentry>
1111                                 <term><command>poweroff</command></term>
1112
1113                                 <listitem><para>Shut down and
1114                                 power-off the system. This is mostly
1115                                 equivalent to <command>start
1116                                 poweroff.target</command> but also
1117                                 prints a wall message to all users. If
1118                                 combined with <option>--force</option>
1119                                 shutdown of all running services is
1120                                 skipped, however all processes are
1121                                 killed and all file systems are
1122                                 unmounted or mounted read-only,
1123                                 immediately followed by the powering
1124                                 off. If <option>--force</option> is
1125                                 specified twice the operation is
1126                                 immediately executed without
1127                                 terminating any processes or
1128                                 unmounting any file systems. This may
1129                                 result in data loss.</para></listitem>
1130                         </varlistentry>
1131                         <varlistentry>
1132                                 <term><command>reboot</command></term>
1133
1134                                 <listitem><para>Shut down and reboot
1135                                 the system. This is mostly equivalent
1136                                 to <command>start
1137                                 reboot.target</command> but also
1138                                 prints a wall message to all users. If
1139                                 combined with <option>--force</option>
1140                                 shutdown of all running services is
1141                                 skipped, however all processes are
1142                                 killed and all file systems are
1143                                 unmounted or mounted read-only,
1144                                 immediately followed by the reboot. If
1145                                 <option>--force</option> is specified
1146                                 twice the operation is immediately
1147                                 executed without terminating any
1148                                 processes or unmounting any file
1149                                 systems. This may result in data
1150                                 loss.</para></listitem>
1151                         </varlistentry>
1152                         <varlistentry>
1153                                 <term><command>kexec</command></term>
1154
1155                                 <listitem><para>Shut down and reboot
1156                                 the system via kexec. This is mostly
1157                                 equivalent to <command>start
1158                                 kexec.target</command> but also prints
1159                                 a wall message to all users. If
1160                                 combined with <option>--force</option>
1161                                 shutdown of all running services is
1162                                 skipped, however all processes are killed
1163                                 and all file systems are unmounted or
1164                                 mounted read-only, immediately
1165                                 followed by the
1166                                 reboot.</para></listitem>
1167                         </varlistentry>
1168                         <varlistentry>
1169                                 <term><command>exit</command></term>
1170
1171                                 <listitem><para>Ask the systemd
1172                                 manager to quit. This is only
1173                                 supported for user service managers
1174                                 (i.e. in conjunction with the
1175                                 <option>--user</option> option) and
1176                                 will fail otherwise.</para></listitem>
1177                         </varlistentry>
1178                         <varlistentry>
1179                                 <term><command>suspend</command></term>
1180
1181                                 <listitem><para>Suspend the
1182                                 system. This will trigger activation
1183                                 of the special
1184                                 <filename>suspend.target</filename>
1185                                 target.</para></listitem>
1186                         </varlistentry>
1187                         <varlistentry>
1188                                 <term><command>hibernate</command></term>
1189
1190                                 <listitem><para>Hibernate the
1191                                 system. This will trigger activation
1192                                 of the special
1193                                 <filename>hibernate.target</filename>
1194                                 target.</para></listitem>
1195                         </varlistentry>
1196                         <varlistentry>
1197                                 <term><command>hybrid-sleep</command></term>
1198
1199                                 <listitem><para>Hibernate and suspend
1200                                 the system. This will trigger
1201                                 activation of the special
1202                                 <filename>hybrid-sleep.target</filename>
1203                                 target.</para></listitem>
1204                         </varlistentry>
1205                         <varlistentry>
1206                                 <term><command>switch-root [ROOT] [INIT]</command></term>
1207
1208                                 <listitem><para>Switches to a
1209                                 different root directory and executes
1210                                 a new system manager process below
1211                                 it. This is intended for usage in
1212                                 initial RAM disks ("initrd"), and will
1213                                 transition from the initrd's system
1214                                 manager process (a.k.a "init" process)
1215                                 to the main system manager
1216                                 process. Takes two arguments: the
1217                                 directory to make the new root
1218                                 directory, and the path to the new
1219                                 system manager binary below it to
1220                                 execute as PID 1. If the latter is
1221                                 omitted or the empty string, a
1222                                 systemd binary will automatically be
1223                                 searched for and used as init. If the
1224                                 system manager path is omitted or
1225                                 equal the empty string the state of
1226                                 the initrd's system manager process is
1227                                 passed to the main system manager,
1228                                 which allows later introspection of the
1229                                 state of the services involved in the
1230                                 initrd boot.</para></listitem>
1231                         </varlistentry>
1232                 </variablelist>
1233
1234         </refsect1>
1235
1236         <refsect1>
1237                 <title>Exit status</title>
1238
1239                 <para>On success 0 is returned, a non-zero failure
1240                 code otherwise.</para>
1241         </refsect1>
1242
1243         <refsect1>
1244                 <title>Environment</title>
1245
1246                 <variablelist>
1247                         <varlistentry>
1248                                 <term><varname>$SYSTEMD_PAGER</varname></term>
1249                                 <listitem><para>Pager to use when
1250                                 <option>--no-pager</option> is not given;
1251                                 overrides <varname>$PAGER</varname>.  Setting
1252                                 this to an empty string or the value
1253                                 <literal>cat</literal> is equivalent to passing
1254                                 <option>--no-pager</option>.</para></listitem>
1255                         </varlistentry>
1256                 </variablelist>
1257         </refsect1>
1258
1259         <refsect1>
1260                 <title>See Also</title>
1261                 <para>
1262                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1263                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1264                         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1265                         <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1266                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1267                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1268                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1269                         <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1270                 </para>
1271         </refsect1>
1272
1273 </refentry>