man/systemctl.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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   6   This file is part of systemd.
   7
   8   Copyright 2010 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
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  18   Lesser General Public License for more details.
  19
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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>The argument should
  91                                 be a unit type name such as
  92                                 <option>service</option> and
  93                                 <option>socket</option>,
  94                                 or a unit load state such as
  95                                 <option>loaded</option> and
  96                                 <option>masked</option>.
  97                                 </para>
  98
  99                                 <para>If the argument is a unit type,
 100                                 when listing units, limit display to
 101                                 certain unit types. If not specified
 102                                 units of all types will be shown.</para>
 103
 104                                 <para>If the argument is a unit load state,
 105                                 when listing units, limit display to
 106                                 certain unit types. If not specified
 107                                 units of in all load states will be
 108                                 shown.</para>
 109                                 </listitem>
 110                         </varlistentry>
 111
 112                         <varlistentry>
 113                                 <term><option>--property=</option></term>
 114                                 <term><option>-p</option></term>
 115
 116                                 <listitem><para>When showing
 117                                 unit/job/manager properties, limit
 118                                 display to certain properties as
 119                                 specified as argument. If not
 120                                 specified all set properties are
 121                                 shown. The argument should be a
 122                                 property name, such as
 123                                 <literal>MainPID</literal>. If
 124                                 specified more than once all
 125                                 properties with the specified names
 126                                 are shown.</para></listitem>
 127                         </varlistentry>
 128
 129                         <varlistentry>
 130                                 <term><option>--all</option></term>
 131                                 <term><option>-a</option></term>
 132
 133                                 <listitem><para>When listing units,
 134                                 show all units, regardless of their
 135                                 state, including inactive units. When
 136                                 showing unit/job/manager properties,
 137                                 show all properties regardless whether
 138                                 they are set or not.</para></listitem>
 139                         </varlistentry>
 140
 141                         <varlistentry>
 142                                 <term><option>--failed</option></term>
 143
 144                                 <listitem><para>When listing units,
 145                                 show only failed units. Do not confuse
 146                                 with
 147                                 <option>--fail</option>.</para></listitem>
 148                         </varlistentry>
 149
 150                         <varlistentry>
 151                                 <term><option>--full</option></term>
 152
 153                                 <listitem><para>Do not ellipsize unit
 154                                 names and truncate unit descriptions
 155                                 in the output of
 156                                 <command>list-units</command> and
 157                                 <command>list-jobs</command>.</para></listitem>
 158                         </varlistentry>
 159
 160                         <varlistentry>
 161                                 <term><option>--fail</option></term>
 162
 163                                 <listitem><para>If the requested
 164                                 operation conflicts with a pending
 165                                 unfinished job, fail the command. If
 166                                 this is not specified the requested
 167                                 operation will replace the pending job,
 168                                 if necessary. Do not confuse
 169                                 with
 170                                 <option>--failed</option>.</para></listitem>
 171                         </varlistentry>
 172
 173                         <varlistentry>
 174                                 <term><option>--ignore-dependencies</option></term>
 175
 176                                 <listitem><para>When enqueuing a new
 177                                 job ignore all its dependencies and
 178                                 execute it immediately. If passed no
 179                                 required units of the unit passed will
 180                                 be pulled in, and no ordering
 181                                 dependencies will be honored. This is
 182                                 mostly a debugging and rescue tool for
 183                                 the administrator and should not be
 184                                 used by
 185                                 applications.</para></listitem>
 186                         </varlistentry>
 187
 188                         <varlistentry>
 189                                 <term><option>--quiet</option></term>
 190                                 <term><option>-q</option></term>
 191
 192                                 <listitem><para>Suppress output to
 193                                 STDOUT in
 194                                 <command>snapshot</command>,
 195                                 <command>is-active</command>,
 196                                 <command>enable</command> and
 197                                 <command>disable</command>.</para></listitem>
 198                         </varlistentry>
 199
 200                         <varlistentry>
 201                                 <term><option>--no-block</option></term>
 202
 203                                 <listitem><para>Do not synchronously wait for
 204                                 the requested operation to finish. If this is
 205                                 not specified the job will be verified,
 206                                 enqueued and <command>systemctl</command> will
 207                                 wait until it is completed. By passing this
 208                                 argument it is only verified and
 209                                 enqueued.</para></listitem>
 210                         </varlistentry>
 211
 212                         <varlistentry>
 213                                 <term><option>--no-legend</option></term>
 214
 215                                 <listitem><para>Do not print a legend, i.e.
 216                                 the column headers and the footer with hints.
 217                                 </para></listitem>
 218                         </varlistentry>
 219
 220                         <varlistentry>
 221                                 <term><option>--no-pager</option></term>
 222
 223                                 <listitem><para>Do not pipe output into a
 224                                 pager.</para></listitem>
 225                         </varlistentry>
 226
 227                         <varlistentry>
 228                                 <term><option>--system</option></term>
 229
 230                                 <listitem><para>Talk to the systemd
 231                                 system manager. (Default)</para></listitem>
 232                         </varlistentry>
 233
 234                         <varlistentry>
 235                                 <term><option>--user</option></term>
 236
 237                                 <listitem><para>Talk to the systemd
 238                                 manager of the calling user.</para></listitem>
 239                         </varlistentry>
 240
 241                         <varlistentry>
 242                                 <term><option>--order</option></term>
 243                                 <term><option>--require</option></term>
 244
 245                                 <listitem><para>When used in
 246                                 conjunction with the
 247                                 <command>dot</command> command (see
 248                                 below), selects which dependencies are
 249                                 shown in the dependency graph. If
 250                                 <option>--order</option> is passed
 251                                 only dependencies of type
 252                                 <varname>After=</varname> or
 253                                 <varname>Before=</varname> are
 254                                 shown. If <option>--require</option>
 255                                 is passed only dependencies of type
 256                                 <varname>Requires=</varname>,
 257                                 <varname>RequiresOverridable=</varname>,
 258                                 <varname>Requisite=</varname>,
 259                                 <varname>RequisiteOverridable=</varname>,
 260                                 <varname>Wants=</varname> and
 261                                 <varname>Conflicts=</varname> are
 262                                 shown. If neither is passed, shows
 263                                 dependencies of all these
 264                                 types.</para></listitem>
 265                         </varlistentry>
 266
 267                         <varlistentry>
 268                                 <term><option>--no-wall</option></term>
 269
 270                                 <listitem><para>Don't send wall
 271                                 message before
 272                                 halt, power-off, reboot.</para></listitem>
 273                         </varlistentry>
 274
 275                         <varlistentry>
 276                                 <term><option>--global</option></term>
 277
 278                                 <listitem><para>When used with
 279                                 <command>enable</command> and
 280                                 <command>disable</command>, operate on the
 281                                 global user configuration
 282                                 directory, thus enabling or disabling
 283                                 a unit file globally for all future
 284                                 logins of all users.</para></listitem>
 285                         </varlistentry>
 286
 287                         <varlistentry>
 288                                 <term><option>--no-reload</option></term>
 289
 290                                 <listitem><para>When used with
 291                                 <command>enable</command> and
 292                                 <command>disable</command>, do not
 293                                 implicitly reload daemon configuration
 294                                 after executing the
 295                                 changes.</para></listitem>
 296                         </varlistentry>
 297
 298                         <varlistentry>
 299                                 <term><option>--no-ask-password</option></term>
 300
 301                                 <listitem><para>When used with
 302                                 <command>start</command> and related
 303                                 commands, disables asking for
 304                                 passwords. Background services may
 305                                 require input of a password or
 306                                 passphrase string, for example to
 307                                 unlock system hard disks or
 308                                 cryptographic certificates. Unless
 309                                 this option is specified and the
 310                                 command is invoked from a terminal
 311                                 <command>systemctl</command> will
 312                                 query the user on the terminal for the
 313                                 necessary secrets. Use this option to
 314                                 switch this behavior off. In this case
 315                                 the password must be supplied by some
 316                                 other means (for example graphical
 317                                 password agents) or the service might
 318                                 fail. This also disables querying the
 319                                 user for authentication for privileged
 320                                 operations.</para></listitem>
 321                         </varlistentry>
 322
 323                         <varlistentry>
 324                                 <term><option>--kill-who=</option></term>
 325
 326                                 <listitem><para>When used with
 327                                 <command>kill</command>, choose which
 328                                 processes to kill. Must be one of
 329                                 <option>main</option>,
 330                                 <option>control</option> or
 331                                 <option>all</option> to select whether
 332                                 to kill only the main process of the
 333                                 unit, the control process or all
 334                                 processes of the unit. If omitted
 335                                 defaults to
 336                                 <option>all</option>.</para></listitem>
 337                         </varlistentry>
 338
 339                         <varlistentry>
 340                                 <term><option>--signal=</option></term>
 341                                 <term><option>-s</option></term>
 342
 343                                 <listitem><para>When used with
 344                                 <command>kill</command>, choose which
 345                                 signal to send to selected
 346                                 processes. Must be one of the well
 347                                 known signal specifiers such as
 348                                 SIGTERM, SIGINT or SIGSTOP. If
 349                                 omitted defaults to
 350                                 <option>SIGTERM</option>.</para></listitem>
 351                         </varlistentry>
 352
 353                         <varlistentry>
 354                                 <term><option>--force</option></term>
 355                                 <term><option>-f</option></term>
 356
 357                                 <listitem><para>When used with
 358                                 <command>enable</command>, overwrite any
 359                                 existing conflicting
 360                                 symlinks.</para></listitem>
 361
 362                                 <listitem><para>When used with
 363                                 <command>halt</command>,
 364                                 <command>poweroff</command>,
 365                                 <command>reboot</command> or
 366                                 <command>kexec</command> execute the
 367                                 selected operation without shutting
 368                                 down all units. However, all processes
 369                                 will be killed forcibly and all file
 370                                 systems are unmounted or remounted
 371                                 read-only. This is hence a drastic but
 372                                 relatively safe option to request an
 373                                 immediate reboot. If
 374                                 <option>--force</option> is specified
 375                                 twice for these operations, they will
 376                                 be executed immediately without
 377                                 terminating any processes or umounting
 378                                 any file systems. Warning: specifying
 379                                 <option>--force</option> twice with
 380                                 any of these operations might result
 381                                 in data loss.</para></listitem>
 382                         </varlistentry>
 383
 384                         <varlistentry>
 385                                 <term><option>--root=</option></term>
 386
 387                                 <listitem><para>When used with
 388                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and
 389                                 related commands), use alternative
 390                                 root path when looking for unit
 391                                 files.</para></listitem>
 392                         </varlistentry>
 393
 394                         <varlistentry>
 395                                 <term><option>--runtime</option></term>
 396
 397                                 <listitem><para>When used with
 398                                 <command>enable</command>/<command>disable</command>/<command>is-enabled</command> (and related commands), make
 399                                 changes only temporarily, so that they
 400                                 are dropped on the next reboot. This
 401                                 will have the effect that changes are
 402                                 not made in subdirectories of
 403                                 <filename>/etc</filename> but in
 404                                 <filename>/run</filename>, with
 405                                 identical immediate effects, however,
 406                                 since the latter is lost on reboot,
 407                                 the changes are lost
 408                                 too.</para></listitem>
 409                         </varlistentry>
 410
 411                         <varlistentry>
 412                                 <term><option>-H</option></term>
 413                                 <term><option>--host</option></term>
 414
 415                                 <listitem><para>Execute operation
 416                                 remotely. Specify a hostname, or
 417                                 username and hostname separated by @,
 418                                 to connect to. This will use SSH to
 419                                 talk to the remote systemd
 420                                 instance.</para></listitem>
 421                         </varlistentry>
 422
 423                         <varlistentry>
 424                                 <term><option>-P</option></term>
 425                                 <term><option>--privileged</option></term>
 426
 427                                 <listitem><para>Acquire privileges via
 428                                 PolicyKit before executing the
 429                                 operation.</para></listitem>
 430                         </varlistentry>
 431
 432                         <varlistentry>
 433                                 <term><option>--lines=</option></term>
 434                                 <term><option>-n</option></term>
 435
 436                                 <listitem><para>When used with
 437                                 <command>status</command> controls the
 438                                 number of journal lines to show,
 439                                 counting from the most recent
 440                                 ones. Takes a positive integer
 441                                 argument. Defaults to
 442                                 10.</para></listitem>
 443                         </varlistentry>
 444
 445                         <varlistentry>
 446                                 <term><option>--output=</option></term>
 447                                 <term><option>-o</option></term>
 448
 449                                 <listitem><para>When used with
 450                                 <command>status</command> controls the
 451                                 formatting of the journal entries that
 452                                 are shown. For the available choices
 453                                 see
 454                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Defaults
 455                                 to
 456                                 <literal>short</literal>.</para></listitem>
 457                         </varlistentry>
 458
 459                 </variablelist>
 460
 461                 <para>The following commands are understood:</para>
 462
 463                 <variablelist>
 464                         <varlistentry>
 465                                 <term><command>list-units</command></term>
 466
 467                                 <listitem><para>List known units.</para></listitem>
 468                         </varlistentry>
 469                         <varlistentry>
 470                                 <term><command>start [NAME...]</command></term>
 471
 472                                 <listitem><para>Start (activate) one
 473                                 or more units specified on the command
 474                                 line.</para></listitem>
 475                         </varlistentry>
 476                         <varlistentry>
 477                                 <term><command>stop [NAME...]</command></term>
 478
 479                                 <listitem><para>Stop (deactivate) one
 480                                 or more units specified on the command
 481                                 line.</para></listitem>
 482                         </varlistentry>
 483                         <varlistentry>
 484                                 <term><command>reload [NAME...]</command></term>
 485
 486                                 <listitem><para>Asks all units listed
 487                                 on the command line to reload their
 488                                 configuration. Note that this will
 489                                 reload the service-specific
 490                                 configuration, not the unit
 491                                 configuration file of systemd. If you
 492                                 want systemd to reload the
 493                                 configuration file of a unit use the
 494                                 <command>daemon-reload</command>
 495                                 command. In other words: for the
 496                                 example case of Apache, this will
 497                                 reload Apache's
 498                                 <filename>httpd.conf</filename> in the
 499                                 web server, not the
 500                                 <filename>apache.service</filename>
 501                                 systemd unit file. </para>
 502
 503                                 <para>This command should not be
 504                                 confused with the
 505                                 <command>daemon-reload</command> or
 506                                 <command>load</command>
 507                                 commands.</para></listitem>
 508
 509                         </varlistentry>
 510                         <varlistentry>
 511                                 <term><command>restart [NAME...]</command></term>
 512
 513                                 <listitem><para>Restart one or more
 514                                 units specified on the command
 515                                 line. If the units are not running yet
 516                                 they will be
 517                                 started.</para></listitem>
 518                         </varlistentry>
 519                         <varlistentry>
 520                                 <term><command>try-restart [NAME...]</command></term>
 521
 522                                 <listitem><para>Restart one or more
 523                                 units specified on the command
 524                                 line if the units are running. Do
 525                                 nothing if units are not running.
 526                                 Note that for compatibility
 527                                 with Red Hat init scripts
 528                                 <command>condrestart</command> is
 529                                 equivalent to this command.</para></listitem>
 530                         </varlistentry>
 531                         <varlistentry>
 532                                 <term><command>reload-or-restart [NAME...]</command></term>
 533
 534                                 <listitem><para>Reload one or more
 535                                 units if they support it. If not,
 536                                 restart them instead. If the units
 537                                 are not running yet they will be
 538                                 started.</para></listitem>
 539                         </varlistentry>
 540                         <varlistentry>
 541                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 542
 543                                 <listitem><para>Reload one or more
 544                                 units if they support it. If not,
 545                                 restart them instead. Do nothing if
 546                                 the units are not running. Note that
 547                                 for compatibility with SysV init
 548                                 scripts
 549                                 <command>force-reload</command> is
 550                                 equivalent to this
 551                                 command.</para></listitem>
 552                         </varlistentry>
 553                         <varlistentry>
 554                                 <term><command>isolate [NAME]</command></term>
 555
 556                                 <listitem><para>Start the unit
 557                                 specified on the command line and its
 558                                 dependencies and stop all others.</para>
 559
 560                                 <para>This is similar to changing the
 561                                 runlevel in a traditional init system. The
 562                                 <command>isolate</command> command will
 563                                 immediately stop processes that are not
 564                                 enabled in the new unit, possibly including
 565                                 the graphical environment or terminal you
 566                                 are currently using.</para>
 567
 568                                 <para>Note that this works only on units
 569                                 where <option>AllowIsolate=</option> is
 570                                 enabled. See
 571                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 572                                 for details.</para></listitem>
 573                         </varlistentry>
 574                         <varlistentry>
 575                                 <term><command>kill [NAME...]</command></term>
 576
 577                                 <listitem><para>Send a signal to one
 578                                 or more processes of the unit. Use
 579                                 <option>--kill-who=</option> to select
 580                                 which process to kill. Use
 581                                 <option>--kill-mode=</option> to
 582                                 select the kill mode and
 583                                 <option>--signal=</option> to select
 584                                 the signal to send.</para></listitem>
 585                         </varlistentry>
 586                         <varlistentry>
 587                                 <term><command>is-active [NAME...]</command></term>
 588
 589                                 <listitem><para>Check whether any of
 590                                 the specified units are active
 591                                 (i.e. running). Returns an exit code
 592                                 0 if at least one is active, non-zero
 593                                 otherwise. Unless
 594                                 <option>--quiet</option> is specified
 595                                 this will also print the current unit
 596                                 state to STDOUT.</para></listitem>
 597                         </varlistentry>
 598                         <varlistentry>
 599                                 <term><command>status [NAME...|PID...]</command></term>
 600
 601                                 <listitem><para>Show terse runtime
 602                                 status information about one or more
 603                                 units, followed by its most recent log
 604                                 data from the journal. This function
 605                                 is intended to generate human-readable
 606                                 output. If you are looking for
 607                                 computer-parsable output, use
 608                                 <command>show</command> instead. If a
 609                                 PID is passed information about the
 610                                 unit the process of the PID belongs to
 611                                 is shown.</para></listitem>
 612                         </varlistentry>
 613                         <varlistentry>
 614                                 <term><command>show [NAME...|JOB...]</command></term>
 615
 616                                 <listitem><para>Show properties of one
 617                                 or more units, jobs or the manager
 618                                 itself. If no argument is specified
 619                                 properties of the manager will be
 620                                 shown. If a unit name is specified
 621                                 properties of the unit is shown, and
 622                                 if a job id is specified properties of
 623                                 the job is shown. By default, empty
 624                                 properties are suppressed. Use
 625                                 <option>--all</option> to show those
 626                                 too. To select specific properties to
 627                                 show use
 628                                 <option>--property=</option>. This
 629                                 command is intended to be used
 630                                 whenever computer-parsable output is
 631                                 required. Use
 632                                 <command>status</command> if you are
 633                                 looking for formatted human-readable
 634                                 output.</para></listitem>
 635                         </varlistentry>
 636                         <varlistentry>
 637                                 <term><command>help [NAME...|PID...]</command></term>
 638
 639                                 <listitem><para>Show manual pages for
 640                                 one or more units, if available. If a
 641                                 PID is passed the manual pages for the
 642                                 unit the process of the PID belongs to
 643                                 is shown.</para></listitem>
 644                         </varlistentry>
 645                         <varlistentry>
 646                                 <term><command>reset-failed [NAME...]</command></term>
 647
 648                                 <listitem><para>Reset the
 649                                 '<literal>failed</literal>' state of the
 650                                 specified units, or if no unit name is
 651                                 passed of all units. When a unit fails
 652                                 in some way (i.e. process exiting with
 653                                 non-zero error code, terminating
 654                                 abnormally or timing out) it will
 655                                 automatically enter the
 656                                 '<literal>failed</literal>' state and
 657                                 its exit code and status is recorded
 658                                 for introspection by the administrator
 659                                 until the service is restarted or
 660                                 reset with this
 661                                 command.</para></listitem>
 662                         </varlistentry>
 663
 664                         <varlistentry>
 665                                 <term><command>list-unit-files</command></term>
 666
 667                                 <listitem><para>List installed unit files.
 668                                 </para></listitem>
 669                         </varlistentry>
 670
 671                         <varlistentry>
 672                                 <term><command>enable [NAME...]</command></term>
 673
 674                                 <listitem><para>Enable one or
 675                                 more unit files or unit file
 676                                 instances, as specified on the
 677                                 command line. This will create a
 678                                 number of symlinks as encoded in
 679                                 the <literal>[Install]</literal>
 680                                 sections of the unit files. After
 681                                 the symlinks have been created the
 682                                 systemd configuration is reloaded
 683                                 (in a way that is equivalent to
 684                                 <command>daemon-reload</command>)
 685                                 to ensure the changes are taken into
 686                                 account immediately. Note that this
 687                                 does not have the effect that any of
 688                                 the units enabled are also started at
 689                                 the same time.  If this is desired
 690                                 a separate <command>start</command>
 691                                 command must be invoked for the unit.
 692                                 Also note that in case of instance
 693                                 enablement, symlinks named same as
 694                                 instances are created in install
 695                                 location, however they all point to
 696                                 the same template unit file.</para>
 697
 698                                 <para>This command will
 699                                 print the actions executed. This
 700                                 output may be suppressed by passing
 701                                 <option>--quiet</option>.</para>
 702
 703                                 <para>Note that this operation creates
 704                                 only the suggested symlinks for the
 705                                 units. While this command is the
 706                                 recommended way to manipulate the unit
 707                                 configuration directory, the
 708                                 administrator is free to make
 709                                 additional changes manually, by
 710                                 placing or removing symlinks in the
 711                                 directory. This is particularly useful
 712                                 to create configurations that deviate
 713                                 from the suggested default
 714                                 installation. In this case the
 715                                 administrator must make sure to invoke
 716                                 <command>daemon-reload</command>
 717                                 manually as necessary, to ensure his
 718                                 changes are taken into account.</para>
 719
 720                                 <para>Enabling units should not be
 721                                 confused with starting (activating)
 722                                 units, as done by the
 723                                 <command>start</command>
 724                                 command. Enabling and starting units
 725                                 is orthogonal: units may be enabled
 726                                 without being started and started
 727                                 without being enabled. Enabling simply
 728                                 hooks the unit into various suggested
 729                                 places (for example, so that the unit
 730                                 is automatically started on boot or
 731                                 when a particular kind of hardware is
 732                                 plugged in). Starting actually spawns
 733                                 the daemon process (in case of service
 734                                 units), or binds the socket (in case
 735                                 of socket units), and so
 736                                 on.</para>
 737
 738                                 <para>Depending on whether
 739                                 <option>--system</option>,
 740                                 <option>--user</option> or
 741                                 <option>--global</option> is specified
 742                                 this enables the unit for the system,
 743                                 for the calling user only
 744                                 or for all future logins of all
 745                                 users. Note that in the latter case no
 746                                 systemd daemon configuration is
 747                                 reloaded.</para>
 748                                 </listitem>
 749                         </varlistentry>
 750
 751                         <varlistentry>
 752                                 <term><command>disable [NAME...]</command></term>
 753
 754                                 <listitem><para>Disables one or more
 755                                 units. This removes all symlinks to
 756                                 the specified unit files from the unit
 757                                 configuration directory, and hence
 758                                 undoes the changes made by
 759                                 <command>enable</command>. Note
 760                                 however that this removes
 761                                 all symlinks to the unit files
 762                                 (i.e. including manual additions), not
 763                                 just those actually created by
 764                                 <command>enable</command>. This call
 765                                 implicitly reloads the systemd daemon
 766                                 configuration after completing the
 767                                 disabling of the units. Note that this
 768                                 command does not implicitly stop the
 769                                 units that are being disabled. If this
 770                                 is desired an additional
 771                                 <command>stop</command> command should
 772                                 be executed afterwards.</para>
 773
 774                                 <para>This command will print the
 775                                 actions executed. This output may be
 776                                 suppressed by passing
 777                                 <option>--quiet</option>.</para>
 778                                 </listitem>
 779
 780                                 <para>This command honors
 781                                 <option>--system</option>,
 782                                 <option>--user</option>,
 783                                 <option>--global</option> in a similar
 784                                 way as
 785                                 <command>enable</command>.</para>
 786                         </varlistentry>
 787
 788                         <varlistentry>
 789                                 <term><command>is-enabled [NAME...]</command></term>
 790
 791                                 <listitem><para>Checks whether any of
 792                                 the specified unit files are enabled
 793                                 (as with
 794                                 <command>enable</command>). Returns an
 795                                 exit code of 0 if at least one is
 796                                 enabled, non-zero otherwise. Prints
 797                                 the current enable status. To suppress
 798                                 this output use
 799                                 <option>--quiet</option>.</para></listitem>
 800                         </varlistentry>
 801
 802                         <varlistentry>
 803                                 <term><command>reenable [NAME...]</command></term>
 804
 805                                 <listitem><para>Reenable one or more
 806                                 unit files, as specified on the
 807                                 command line. This is a combination of
 808                                 <command>disable</command> and
 809                                 <command>enable</command> and is
 810                                 useful to reset the symlinks a unit is
 811                                 enabled with to the defaults
 812                                 configured in the
 813                                 <literal>[Install]</literal> section
 814                                 of the unit file.</para>
 815                                 </listitem>
 816                         </varlistentry>
 817
 818                         <varlistentry>
 819                                 <term><command>preset [NAME...]</command></term>
 820
 821                                 <listitem><para>Reset one or more unit
 822                                 files, as specified on the command
 823                                 line, to the defaults configured in
 824                                 the preset policy files. This has the
 825                                 same effect as
 826                                 <command>disable</command> or
 827                                 <command>enable</command>, depending
 828                                 how the unit is listed in the preset
 829                                 files. For more information on preset
 830                                 policy format see
 831                                 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 832                                 more information on the concept of
 833                                 presets please consult the <ulink
 834                                 url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
 835                                 document.</para>
 836                                 </listitem>
 837                         </varlistentry>
 838
 839                         <varlistentry>
 840                                 <term><command>mask [NAME...]</command></term>
 841
 842                                 <listitem><para>Mask one or more unit
 843                                 files, as specified on the command
 844                                 line. This will link these units to
 845                                 <filename>/dev/null</filename>, making
 846                                 it impossible to start them. This is a stronger version
 847                                 of <command>disable</command>, since
 848                                 it prohibits all kinds of activation
 849                                 of the unit, including manual
 850                                 activation. Use this option with
 851                                 care.</para>
 852                                 </listitem>
 853                         </varlistentry>
 854
 855                         <varlistentry>
 856                                 <term><command>unmask [NAME...]</command></term>
 857
 858                                 <listitem><para>Unmask one or more
 859                                 unit files, as specified on the
 860                                 command line. This will undo the
 861                                 effect of
 862                                 <command>mask</command>.</para>
 863                                 </listitem>
 864                         </varlistentry>
 865
 866                         <varlistentry>
 867                                 <term><command>link [NAME...]</command></term>
 868
 869                                 <listitem><para>Link a unit file that
 870                                 is not in the unit file search paths
 871                                 into the unit file search path. This
 872                                 requires an absolute path to a unit
 873                                 file. The effect of this can be undone
 874                                 with <command>disable</command>. The
 875                                 effect of this command is that a unit
 876                                 file is available for
 877                                 <command>start</command> and other
 878                                 commands although it isn't installed
 879                                 directly in the unit search
 880                                 path.</para>
 881                                 </listitem>
 882                         </varlistentry>
 883
 884                         <varlistentry>
 885                                 <term><command>load [NAME...]</command></term>
 886
 887                                 <listitem><para>Load one or more units
 888                                 specified on the command line. This
 889                                 will simply load their configuration
 890                                 from disk, but not start them. To
 891                                 start them you need to use the
 892                                 <command>start</command> command which
 893                                 will implicitly load a unit that has
 894                                 not been loaded yet. Note that systemd
 895                                 garbage collects loaded units that are
 896                                 not active or referenced by an active
 897                                 unit. This means that units loaded
 898                                 this way will usually not stay loaded
 899                                 for long. Also note that this command
 900                                 cannot be used to reload unit
 901                                 configuration. Use the
 902                                 <command>daemon-reload</command>
 903                                 command for that. All in all, this
 904                                 command is of little use except for
 905                                 debugging.</para>
 906                                 <para>This command should not be
 907                                 confused with the
 908                                 <command>daemon-reload</command> or
 909                                 <command>reload</command>
 910                                 commands.</para></listitem>
 911                         </varlistentry>
 912                         <varlistentry>
 913                                 <term><command>list-jobs</command></term>
 914
 915                                 <listitem><para>List jobs that are in progress.</para></listitem>
 916                         </varlistentry>
 917                         <varlistentry>
 918                                 <term><command>cancel [JOB...]</command></term>
 919
 920                                 <listitem><para>Cancel one or more
 921                                 jobs specified on the command line by
 922                                 their numeric job
 923                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 924                         </varlistentry>
 925                         <varlistentry>
 926                                 <term><command>dump</command></term>
 927
 928                                 <listitem><para>Dump server
 929                                 status. This will output a (usually
 930                                 very long) human readable manager
 931                                 status dump. Its format is subject to
 932                                 change without notice and should not
 933                                 be parsed by
 934                                 applications.</para></listitem>
 935                         </varlistentry>
 936                         <varlistentry>
 937                                 <term><command>dot</command></term>
 938
 939                                 <listitem><para>Generate textual
 940                                 dependency graph description in dot
 941                                 format for further processing with the
 942                                 GraphViz
 943                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 944                                 tool. Use a command line like
 945                                 <command>systemctl dot | dot -Tsvg >
 946                                 systemd.svg</command> to generate a
 947                                 graphical dependency tree. Unless
 948                                 <option>--order</option> or
 949                                 <option>--require</option> is passed
 950                                 the generated graph will show both
 951                                 ordering and requirement
 952                                 dependencies.</para></listitem>
 953                         </varlistentry>
 954                         <varlistentry>
 955                                 <term><command>snapshot [NAME]</command></term>
 956
 957                                 <listitem><para>Create a snapshot. If
 958                                 a snapshot name is specified, the new
 959                                 snapshot will be named after it. If
 960                                 none is specified an automatic
 961                                 snapshot name is generated. In either
 962                                 case, the snapshot name used is
 963                                 printed to STDOUT, unless
 964                                 <option>--quiet</option> is
 965                                 specified.</para>
 966
 967                                 <para>A snapshot refers to a saved
 968                                 state of the systemd manager. It is
 969                                 implemented itself as a unit that is
 970                                 generated dynamically with this
 971                                 command and has dependencies on all
 972                                 units active at the time. At a later
 973                                 time the user may return to this state
 974                                 by using the
 975                                 <command>isolate</command> command on
 976                                 the snapshot unit.</para></listitem>
 977
 978                                 <para>Snapshots are only useful for
 979                                 saving and restoring which units are
 980                                 running or are stopped, they do not
 981                                 save/restore any other
 982                                 state. Snapshots are dynamic and lost
 983                                 on reboot.</para>
 984                         </varlistentry>
 985                         <varlistentry>
 986                                 <term><command>delete [NAME...]</command></term>
 987
 988                                 <listitem><para>Remove a snapshot
 989                                 previously created with
 990                                 <command>snapshot</command>.</para></listitem>
 991                         </varlistentry>
 992                         <varlistentry>
 993                                 <term><command>daemon-reload</command></term>
 994
 995                                 <listitem><para>Reload systemd manager
 996                                 configuration. This will reload all
 997                                 unit files and recreate the entire
 998                                 dependency tree. While the daemon is
 999                                 reloaded, all sockets systemd listens
1000                                 on on behalf of user configuration will
1001                                 stay accessible.</para> <para>This
1002                                 command should not be confused with
1003                                 the <command>load</command> or
1004                                 <command>reload</command>
1005                                 commands.</para></listitem>
1006                         </varlistentry>
1007                         <varlistentry>
1008                                 <term><command>daemon-reexec</command></term>
1009
1010                                 <listitem><para>Reexecute the systemd
1011                                 manager. This will serialize the
1012                                 manager state, reexecute the process
1013                                 and deserialize the state again. This
1014                                 command is of little use except for
1015                                 debugging and package
1016                                 upgrades. Sometimes it might be
1017                                 helpful as a heavy-weight
1018                                 <command>daemon-reload</command>. While
1019                                 the daemon is reexecuted all sockets
1020                                 systemd listens on on behalf of user
1021                                 configuration will stay
1022                                 accessible.</para></listitem>
1023                         </varlistentry>
1024                         <varlistentry>
1025                                 <term><command>show-environment</command></term>
1026
1027                                 <listitem><para>Dump the systemd
1028                                 manager environment block. The
1029                                 environment block will be dumped in
1030                                 straight-forward form suitable for
1031                                 sourcing into a shell script. This
1032                                 environment block will be passed to
1033                                 all processes the manager
1034                                 spawns.</para></listitem>
1035                         </varlistentry>
1036                         <varlistentry>
1037                                 <term><command>set-environment [NAME=VALUE...]</command></term>
1038
1039                                 <listitem><para>Set one or more
1040                                 systemd manager environment variables,
1041                                 as specified on the command
1042                                 line.</para></listitem>
1043                         </varlistentry>
1044                         <varlistentry>
1045                                 <term><command>unset-environment [NAME...]</command></term>
1046
1047                                 <listitem><para>Unset one or more
1048                                 systemd manager environment
1049                                 variables. If only a variable name is
1050                                 specified it will be removed
1051                                 regardless of its value. If a variable
1052                                 and a value are specified the variable
1053                                 is only removed if it has the
1054                                 specified value.</para></listitem>
1055                         </varlistentry>
1056                         <varlistentry>
1057                                 <term><command>default</command></term>
1058
1059                                 <listitem><para>Enter default
1060                                 mode. This is mostly equivalent to
1061                                 <command>start
1062                                 default.target</command>.</para></listitem>
1063                         </varlistentry>
1064                         <varlistentry>
1065                                 <term><command>rescue</command></term>
1066
1067                                 <listitem><para>Enter rescue
1068                                 mode. This is mostly equivalent to
1069                                 <command>isolate
1070                                 rescue.target</command> but also
1071                                 prints a wall message to all
1072                                 users.</para></listitem>
1073                         </varlistentry>
1074                         <varlistentry>
1075                                 <term><command>emergency</command></term>
1076
1077                                 <listitem><para>Enter emergency
1078                                 mode. This is mostly equivalent to
1079                                 <command>isolate
1080                                 emergency.target</command> but also
1081                                 prints a wall message to all
1082                                 users.</para></listitem>
1083                         </varlistentry>
1084                         <varlistentry>
1085                                 <term><command>halt</command></term>
1086
1087                                 <listitem><para>Shut down and halt the
1088                                 system. This is mostly equivalent to
1089                                 <command>start halt.target</command>
1090                                 but also prints a wall message to all
1091                                 users.  If combined with
1092                                 <option>--force</option> shutdown of
1093                                 all running services is skipped,
1094                                 however all processes are killed and
1095                                 all file systems are unmounted or
1096                                 mounted read-only, immediately
1097                                 followed by the system halt.  If
1098                                 <option>--force</option> is specified
1099                                 twice the operation is immediately
1100                                 executed without terminating any
1101                                 processes or unmounting any file
1102                                 systems. This may result in data
1103                                 loss.</para></listitem>
1104                         </varlistentry>
1105                         <varlistentry>
1106                                 <term><command>poweroff</command></term>
1107
1108                                 <listitem><para>Shut down and
1109                                 power-off the system. This is mostly
1110                                 equivalent to <command>start
1111                                 poweroff.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 powering
1119                                 off. If <option>--force</option> is
1120                                 specified twice the operation is
1121                                 immediately executed without
1122                                 terminating any processes or
1123                                 unmounting any file systems. This may
1124                                 result in data loss.</para></listitem>
1125                         </varlistentry>
1126                         <varlistentry>
1127                                 <term><command>reboot</command></term>
1128
1129                                 <listitem><para>Shut down and reboot
1130                                 the system. This is mostly equivalent
1131                                 to <command>start
1132                                 reboot.target</command> but also
1133                                 prints 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
1137                                 killed and all file systems are
1138                                 unmounted or mounted read-only,
1139                                 immediately followed by the reboot. If
1140                                 <option>--force</option> is specified
1141                                 twice the operation is immediately
1142                                 executed without terminating any
1143                                 processes or unmounting any file
1144                                 systems. This may result in data
1145                                 loss.</para></listitem>
1146                         </varlistentry>
1147                         <varlistentry>
1148                                 <term><command>kexec</command></term>
1149
1150                                 <listitem><para>Shut down and reboot
1151                                 the system via kexec. This is mostly
1152                                 equivalent to <command>start
1153                                 kexec.target</command> but also prints
1154                                 a wall message to all users. If
1155                                 combined with <option>--force</option>
1156                                 shutdown of all running services is
1157                                 skipped, however all processes are killed
1158                                 and all file systems are unmounted or
1159                                 mounted read-only, immediately
1160                                 followed by the
1161                                 reboot.</para></listitem>
1162                         </varlistentry>
1163                         <varlistentry>
1164                                 <term><command>exit</command></term>
1165
1166                                 <listitem><para>Ask the systemd
1167                                 manager to quit. This is only
1168                                 supported for user service managers
1169                                 (i.e. in conjunction with the
1170                                 <option>--user</option> option) and
1171                                 will fail otherwise.</para></listitem>
1172                         </varlistentry>
1173                         <varlistentry>
1174                                 <term><command>suspend</command></term>
1175
1176                                 <listitem><para>Suspend the
1177                                 system. This will trigger activation
1178                                 of the special
1179                                 <filename>suspend.target</filename>
1180                                 target.</para></listitem>
1181                         </varlistentry>
1182                         <varlistentry>
1183                                 <term><command>hibernate</command></term>
1184
1185                                 <listitem><para>Hibernate the
1186                                 system. This will trigger activation
1187                                 of the special
1188                                 <filename>hibernate.target</filename>
1189                                 target.</para></listitem>
1190                         </varlistentry>
1191                         <varlistentry>
1192                                 <term><command>hybrid-sleep</command></term>
1193
1194                                 <listitem><para>Hibernate and suspend
1195                                 the system. This will trigger
1196                                 activation of the special
1197                                 <filename>hybrid-sleep.target</filename>
1198                                 target.</para></listitem>
1199                         </varlistentry>
1200                         <varlistentry>
1201                                 <term><command>switch-root [ROOT] [INIT]</command></term>
1202
1203                                 <listitem><para>Switches to a
1204                                 different root directory and executes
1205                                 a new system manager process below
1206                                 it. This is intended for usage in
1207                                 initial RAM disks ("initrd"), and will
1208                                 transition from the initrd's system
1209                                 manager process (a.k.a "init" process)
1210                                 to the main system manager
1211                                 process. Takes two arguments: the
1212                                 directory to make the new root
1213                                 directory, and the path to the new
1214                                 system manager binary below it to
1215                                 execute as PID 1. If the latter is
1216                                 omitted or the empty string, a
1217                                 systemd binary will automatically be
1218                                 searched for and used as init. If the
1219                                 system manager path is omitted or
1220                                 equal the empty string the state of
1221                                 the initrd's system manager process is
1222                                 passed to the main system manager,
1223                                 which allows later introspection of the
1224                                 state of the services involved in the
1225                                 initrd boot.</para></listitem>
1226                         </varlistentry>
1227                 </variablelist>
1228
1229         </refsect1>
1230
1231         <refsect1>
1232                 <title>Exit status</title>
1233
1234                 <para>On success 0 is returned, a non-zero failure
1235                 code otherwise.</para>
1236         </refsect1>
1237
1238         <refsect1>
1239                 <title>Environment</title>
1240
1241                 <variablelist>
1242                         <varlistentry>
1243                                 <term><varname>$SYSTEMD_PAGER</varname></term>
1244                                 <listitem><para>Pager to use when
1245                                 <option>--no-pager</option> is not given;
1246                                 overrides <varname>$PAGER</varname>.  Setting
1247                                 this to an empty string or the value
1248                                 <literal>cat</literal> is equivalent to passing
1249                                 <option>--no-pager</option>.</para></listitem>
1250                         </varlistentry>
1251                 </variablelist>
1252         </refsect1>
1253
1254         <refsect1>
1255                 <title>See Also</title>
1256                 <para>
1257                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1258                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1259                         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1260                         <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1261                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1262                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1263                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1264                         <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1265                 </para>
1266         </refsect1>
1267
1268 </refentry>