man/systemctl.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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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                                 </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 honoured. 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>--follow</option></term>
 447                                 <term><option>-f</option></term>
 448
 449                                 <listitem><para>When used with
 450                                 <command>status</command> continously
 451                                 prints new journal entries as they are
 452                                 appended to the
 453                                 journal.</para></listitem>
 454                         </varlistentry>
 455
 456                         <varlistentry>
 457                                 <term><option>--output=</option></term>
 458                                 <term><option>-o</option></term>
 459
 460                                 <listitem><para>When used with
 461                                 <command>status</command> controls the
 462                                 formatting of the journal entries that
 463                                 are shown. For the available choices
 464                                 see
 465                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Defaults
 466                                 to
 467                                 <literal>short</literal>.</para></listitem>
 468                         </varlistentry>
 469
 470                 </variablelist>
 471
 472                 <para>The following commands are understood:</para>
 473
 474                 <variablelist>
 475                         <varlistentry>
 476                                 <term><command>list-units</command></term>
 477
 478                                 <listitem><para>List known units.</para></listitem>
 479                         </varlistentry>
 480                         <varlistentry>
 481                                 <term><command>start [NAME...]</command></term>
 482
 483                                 <listitem><para>Start (activate) one
 484                                 or more units specified on the command
 485                                 line.</para></listitem>
 486                         </varlistentry>
 487                         <varlistentry>
 488                                 <term><command>stop [NAME...]</command></term>
 489
 490                                 <listitem><para>Stop (deactivate) one
 491                                 or more units specified on the command
 492                                 line.</para></listitem>
 493                         </varlistentry>
 494                         <varlistentry>
 495                                 <term><command>reload [NAME...]</command></term>
 496
 497                                 <listitem><para>Asks all units listed
 498                                 on the command line to reload their
 499                                 configuration. Note that this will
 500                                 reload the service-specific
 501                                 configuration, not the unit
 502                                 configuration file of systemd. If you
 503                                 want systemd to reload the
 504                                 configuration file of a unit use the
 505                                 <command>daemon-reload</command>
 506                                 command. In other words: for the
 507                                 example case of Apache, this will
 508                                 reload Apache's
 509                                 <filename>httpd.conf</filename> in the
 510                                 web server, not the
 511                                 <filename>apache.service</filename>
 512                                 systemd unit file. </para>
 513
 514                                 <para>This command should not be
 515                                 confused with the
 516                                 <command>daemon-reload</command> or
 517                                 <command>load</command>
 518                                 commands.</para></listitem>
 519
 520                         </varlistentry>
 521                         <varlistentry>
 522                                 <term><command>restart [NAME...]</command></term>
 523
 524                                 <listitem><para>Restart one or more
 525                                 units specified on the command
 526                                 line. If the units are not running yet
 527                                 they will be
 528                                 started.</para></listitem>
 529                         </varlistentry>
 530                         <varlistentry>
 531                                 <term><command>try-restart [NAME...]</command></term>
 532
 533                                 <listitem><para>Restart one or more
 534                                 units specified on the command
 535                                 line if the units are running. Do
 536                                 nothing if units are not running.
 537                                 Note that for compatibility
 538                                 with Red Hat init scripts
 539                                 <command>condrestart</command> is
 540                                 equivalent to this command.</para></listitem>
 541                         </varlistentry>
 542                         <varlistentry>
 543                                 <term><command>reload-or-restart [NAME...]</command></term>
 544
 545                                 <listitem><para>Reload one or more
 546                                 units if they support it. If not,
 547                                 restart them instead. If the units
 548                                 are not running yet they will be
 549                                 started.</para></listitem>
 550                         </varlistentry>
 551                         <varlistentry>
 552                                 <term><command>reload-or-try-restart [NAME...]</command></term>
 553
 554                                 <listitem><para>Reload one or more
 555                                 units if they support it. If not,
 556                                 restart them instead. Do nothing if
 557                                 the units are not running. Note that
 558                                 for compatibility with SysV init
 559                                 scripts
 560                                 <command>force-reload</command> is
 561                                 equivalent to this
 562                                 command.</para></listitem>
 563                         </varlistentry>
 564                         <varlistentry>
 565                                 <term><command>isolate [NAME]</command></term>
 566
 567                                 <listitem><para>Start the unit
 568                                 specified on the command line and its
 569                                 dependencies and stop all others.</para>
 570
 571                                 <para>This is similar to changing the
 572                                 runlevel in a traditional init system. The
 573                                 <command>isolate</command> command will
 574                                 immediately stop processes that are not
 575                                 enabled in the new unit, possibly including
 576                                 the graphical environment or terminal you
 577                                 are currently using.</para>
 578
 579                                 <para>Note that this works only on units
 580                                 where <option>AllowIsolate=</option> is
 581                                 enabled. See
 582                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 583                                 for details.</para></listitem>
 584                         </varlistentry>
 585                         <varlistentry>
 586                                 <term><command>kill [NAME...]</command></term>
 587
 588                                 <listitem><para>Send a signal to one
 589                                 or more processes of the unit. Use
 590                                 <option>--kill-who=</option> to select
 591                                 which process to kill. Use
 592                                 <option>--kill-mode=</option> to
 593                                 select the kill mode and
 594                                 <option>--signal=</option> to select
 595                                 the signal to send.</para></listitem>
 596                         </varlistentry>
 597                         <varlistentry>
 598                                 <term><command>is-active [NAME...]</command></term>
 599
 600                                 <listitem><para>Check whether any of
 601                                 the specified units are active
 602                                 (i.e. running). Returns an exit code
 603                                 0 if at least one is active, non-zero
 604                                 otherwise. Unless
 605                                 <option>--quiet</option> is specified
 606                                 this will also print the current unit
 607                                 state to STDOUT.</para></listitem>
 608                         </varlistentry>
 609                         <varlistentry>
 610                                 <term><command>status [NAME...|PID...]</command></term>
 611
 612                                 <listitem><para>Show terse runtime
 613                                 status information about one or more
 614                                 units, followed by its most recent log
 615                                 data from the journal. This function
 616                                 is intended to generate human-readable
 617                                 output. If you are looking for
 618                                 computer-parsable output, use
 619                                 <command>show</command> instead. If a
 620                                 PID is passed information about the
 621                                 unit the process of the PID belongs to
 622                                 is shown.</para></listitem>
 623                         </varlistentry>
 624                         <varlistentry>
 625                                 <term><command>show [NAME...|JOB...]</command></term>
 626
 627                                 <listitem><para>Show properties of one
 628                                 or more units, jobs or the manager
 629                                 itself. If no argument is specified
 630                                 properties of the manager will be
 631                                 shown. If a unit name is specified
 632                                 properties of the unit is shown, and
 633                                 if a job id is specified properties of
 634                                 the job is shown. By default, empty
 635                                 properties are suppressed. Use
 636                                 <option>--all</option> to show those
 637                                 too. To select specific properties to
 638                                 show use
 639                                 <option>--property=</option>. This
 640                                 command is intended to be used
 641                                 whenever computer-parsable output is
 642                                 required. Use
 643                                 <command>status</command> if you are
 644                                 looking for formatted human-readable
 645                                 output.</para></listitem>
 646                         </varlistentry>
 647                         <varlistentry>
 648                                 <term><command>help [NAME...|PID...]</command></term>
 649
 650                                 <listitem><para>Show manual pages for
 651                                 one or more units, if available. If a
 652                                 PID is passed the manual pages for the
 653                                 unit the process of the PID belongs to
 654                                 is shown.</para></listitem>
 655                         </varlistentry>
 656                         <varlistentry>
 657                                 <term><command>reset-failed [NAME...]</command></term>
 658
 659                                 <listitem><para>Reset the
 660                                 '<literal>failed</literal>' state of the
 661                                 specified units, or if no unit name is
 662                                 passed of all units. When a unit fails
 663                                 in some way (i.e. process exiting with
 664                                 non-zero error code, terminating
 665                                 abnormally or timing out) it will
 666                                 automatically enter the
 667                                 '<literal>failed</literal>' state and
 668                                 its exit code and status is recorded
 669                                 for introspection by the administrator
 670                                 until the service is restarted or
 671                                 reset with this
 672                                 command.</para></listitem>
 673                         </varlistentry>
 674
 675                         <varlistentry>
 676                                 <term><command>list-unit-files</command></term>
 677
 678                                 <listitem><para>List installed unit files.
 679                                 </para></listitem>
 680                         </varlistentry>
 681
 682                         <varlistentry>
 683                                 <term><command>enable [NAME...]</command></term>
 684
 685                                 <listitem><para>Enable one or more
 686                                 unit files, as specified on the
 687                                 command line. This will create a
 688                                 number of symlinks as encoded in the
 689                                 <literal>[Install]</literal> sections
 690                                 of the unit files. After the symlinks
 691                                 have been created the systemd
 692                                 configuration is reloaded (in a way
 693                                 that is equivalent to
 694                                 <command>daemon-reload</command>) to
 695                                 ensure the changes are taken into
 696                                 account immediately. Note that this
 697                                 does not have the effect that any of
 698                                 the units enabled are also started at
 699                                 the same time. If this is desired a
 700                                 separate <command>start</command>
 701                                 command must be invoked for the
 702                                 unit.</para>
 703
 704                                 <para>This command will
 705                                 print the actions executed. This
 706                                 output may be suppressed by passing
 707                                 <option>--quiet</option>.</para>
 708
 709                                 <para>Note that this operation creates
 710                                 only the suggested symlinks for the
 711                                 units. While this command is the
 712                                 recommended way to manipulate the unit
 713                                 configuration directory, the
 714                                 administrator is free to make
 715                                 additional changes manually, by
 716                                 placing or removing symlinks in the
 717                                 directory. This is particularly useful
 718                                 to create configurations that deviate
 719                                 from the suggested default
 720                                 installation. In this case the
 721                                 administrator must make sure to invoke
 722                                 <command>daemon-reload</command>
 723                                 manually as necessary, to ensure his
 724                                 changes are taken into account.</para>
 725
 726                                 <para>Enabling units should not be
 727                                 confused with starting (activating)
 728                                 units, as done by the
 729                                 <command>start</command>
 730                                 command. Enabling and starting units
 731                                 is orthogonal: units may be enabled
 732                                 without being started and started
 733                                 without being enabled. Enabling simply
 734                                 hooks the unit into various suggested
 735                                 places (for example, so that the unit
 736                                 is automatically started on boot or
 737                                 when a particular kind of hardware is
 738                                 plugged in). Starting actually spawns
 739                                 the daemon process (in case of service
 740                                 units), or binds the socket (in case
 741                                 of socket units), and so
 742                                 on.</para>
 743
 744                                 <para>Depending on whether
 745                                 <option>--system</option>,
 746                                 <option>--user</option> or
 747                                 <option>--global</option> is specified
 748                                 this enables the unit for the system,
 749                                 for the calling user only
 750                                 or for all future logins of all
 751                                 users. Note that in the latter case no
 752                                 systemd daemon configuration is
 753                                 reloaded.</para>
 754                                 </listitem>
 755                         </varlistentry>
 756
 757                         <varlistentry>
 758                                 <term><command>disable [NAME...]</command></term>
 759
 760                                 <listitem><para>Disables one or more
 761                                 units. This removes all symlinks to
 762                                 the specified unit files from the unit
 763                                 configuration directory, and hence
 764                                 undoes the changes made by
 765                                 <command>enable</command>. Note
 766                                 however that this removes
 767                                 all symlinks to the unit files
 768                                 (i.e. including manual additions), not
 769                                 just those actually created by
 770                                 <command>enable</command>. This call
 771                                 implicitly reloads the systemd daemon
 772                                 configuration after completing the
 773                                 disabling of the units. Note that this
 774                                 command does not implicitly stop the
 775                                 units that is being disabled. If this
 776                                 is desired an additional
 777                                 <command>stop</command> command should
 778                                 be executed afterwards.</para>
 779
 780                                 <para>This command will print the
 781                                 actions executed. This output may be
 782                                 suppressed by passing
 783                                 <option>--quiet</option>.</para>
 784                                 </listitem>
 785
 786                                 <para>This command honors
 787                                 <option>--system</option>,
 788                                 <option>--user</option>,
 789                                 <option>--global</option> in a similar
 790                                 way as
 791                                 <command>enable</command>.</para>
 792                         </varlistentry>
 793
 794                         <varlistentry>
 795                                 <term><command>is-enabled [NAME...]</command></term>
 796
 797                                 <listitem><para>Checks whether any of
 798                                 the specified unit files is enabled
 799                                 (as with
 800                                 <command>enable</command>). Returns an
 801                                 exit code of 0 if at least one is
 802                                 enabled, non-zero otherwise. Prints
 803                                 the current enable status. To suppress
 804                                 this output use
 805                                 <option>--quiet</option>.</para></listitem>
 806                         </varlistentry>
 807
 808                         <varlistentry>
 809                                 <term><command>reenable [NAME...]</command></term>
 810
 811                                 <listitem><para>Reenable one or more
 812                                 unit files, as specified on the
 813                                 command line. This is a combination of
 814                                 <command>disable</command> and
 815                                 <command>enable</command> and is
 816                                 useful to reset the symlinks a unit is
 817                                 enabled with to the defaults
 818                                 configured in the
 819                                 <literal>[Install]</literal> section
 820                                 of the unit file.</para>
 821                                 </listitem>
 822                         </varlistentry>
 823
 824                         <varlistentry>
 825                                 <term><command>preset [NAME...]</command></term>
 826
 827                                 <listitem><para>Reset one or more unit
 828                                 files, as specified on the command
 829                                 line, to the defaults configured in
 830                                 the preset policy files. This has the
 831                                 same effect as
 832                                 <command>disable</command> or
 833                                 <command>enable</command>, depending
 834                                 how the unit is listed in the preset
 835                                 files. For more information on preset
 836                                 policy format see
 837                                 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 838                                 more information on the concept of
 839                                 presets please consult the <ulink
 840                                 url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
 841                                 document.</para>
 842                                 </listitem>
 843                         </varlistentry>
 844
 845                         <varlistentry>
 846                                 <term><command>mask [NAME...]</command></term>
 847
 848                                 <listitem><para>Mask one or more unit
 849                                 files, as specified on the command
 850                                 line. This will link these units to
 851                                 <filename>/dev/null</filename>, making
 852                                 it impossible to start them. This is a stronger version
 853                                 of <command>disable</command>, since
 854                                 it prohibits all kinds of activation
 855                                 of the unit, including manual
 856                                 activation. Use this option with
 857                                 care.</para>
 858                                 </listitem>
 859                         </varlistentry>
 860
 861                         <varlistentry>
 862                                 <term><command>unmask [NAME...]</command></term>
 863
 864                                 <listitem><para>Unmask one or more
 865                                 unit files, as specified on the
 866                                 command line. This will undo the
 867                                 effect of
 868                                 <command>mask</command>.</para>
 869                                 </listitem>
 870                         </varlistentry>
 871
 872                         <varlistentry>
 873                                 <term><command>link [NAME...]</command></term>
 874
 875                                 <listitem><para>Link a unit file that
 876                                 is not in the unit file search paths
 877                                 into the unit file search path. This
 878                                 requires an absolute path to a unit
 879                                 file. The effect of this can be undone
 880                                 with <command>disable</command>. The
 881                                 effect of this command is that a unit
 882                                 file is available for
 883                                 <command>start</command> and other
 884                                 commands although it isn't installed
 885                                 directly in the unit search
 886                                 path.</para>
 887                                 </listitem>
 888                         </varlistentry>
 889
 890                         <varlistentry>
 891                                 <term><command>load [NAME...]</command></term>
 892
 893                                 <listitem><para>Load one or more units
 894                                 specified on the command line. This
 895                                 will simply load their configuration
 896                                 from disk, but not start them. To
 897                                 start them you need to use the
 898                                 <command>start</command> command which
 899                                 will implicitly load a unit that has
 900                                 not been loaded yet. Note that systemd
 901                                 garbage collects loaded units that are
 902                                 not active or referenced by an active
 903                                 unit. This means that units loaded
 904                                 this way will usually not stay loaded
 905                                 for long. Also note that this command
 906                                 cannot be used to reload unit
 907                                 configuration. Use the
 908                                 <command>daemon-reload</command>
 909                                 command for that. All in all, this
 910                                 command is of little use except for
 911                                 debugging.</para>
 912                                 <para>This command should not be
 913                                 confused with the
 914                                 <command>daemon-reload</command> or
 915                                 <command>reload</command>
 916                                 commands.</para></listitem>
 917                         </varlistentry>
 918                         <varlistentry>
 919                                 <term><command>list-jobs</command></term>
 920
 921                                 <listitem><para>List jobs that are in progress.</para></listitem>
 922                         </varlistentry>
 923                         <varlistentry>
 924                                 <term><command>cancel [JOB...]</command></term>
 925
 926                                 <listitem><para>Cancel one or more
 927                                 jobs specified on the command line by
 928                                 their numeric job
 929                                 IDs. If no job id is specified, cancel all pending jobs.</para></listitem>
 930                         </varlistentry>
 931                         <varlistentry>
 932                                 <term><command>dump</command></term>
 933
 934                                 <listitem><para>Dump server
 935                                 status. This will output a (usually
 936                                 very long) human readable manager
 937                                 status dump. Its format is subject to
 938                                 change without notice and should not
 939                                 be parsed by
 940                                 applications.</para></listitem>
 941                         </varlistentry>
 942                         <varlistentry>
 943                                 <term><command>dot</command></term>
 944
 945                                 <listitem><para>Generate textual
 946                                 dependency graph description in dot
 947                                 format for further processing with the
 948                                 GraphViz
 949                                 <citerefentry><refentrytitle>dot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 950                                 tool. Use a command line like
 951                                 <command>systemctl dot | dot -Tsvg >
 952                                 systemd.svg</command> to generate a
 953                                 graphical dependency tree. Unless
 954                                 <option>--order</option> or
 955                                 <option>--require</option> is passed
 956                                 the generated graph will show both
 957                                 ordering and requirement
 958                                 dependencies.</para></listitem>
 959                         </varlistentry>
 960                         <varlistentry>
 961                                 <term><command>snapshot [NAME]</command></term>
 962
 963                                 <listitem><para>Create a snapshot. If
 964                                 a snapshot name is specified, the new
 965                                 snapshot will be named after it. If
 966                                 none is specified an automatic
 967                                 snapshot name is generated. In either
 968                                 case, the snapshot name used is
 969                                 printed to STDOUT, unless
 970                                 <option>--quiet</option> is
 971                                 specified.</para>
 972
 973                                 <para>A snapshot refers to a saved
 974                                 state of the systemd manager. It is
 975                                 implemented itself as a unit that is
 976                                 generated dynamically with this
 977                                 command and has dependencies on all
 978                                 units active at the time. At a later
 979                                 time the user may return to this state
 980                                 by using the
 981                                 <command>isolate</command> command on
 982                                 the snapshot unit.</para></listitem>
 983
 984                                 <para>Snapshots are only useful for
 985                                 saving and restoring which units are
 986                                 running or are stopped, they do not
 987                                 save/restore any other
 988                                 state. Snapshots are dynamic and lost
 989                                 on reboot.</para>
 990                         </varlistentry>
 991                         <varlistentry>
 992                                 <term><command>delete [NAME...]</command></term>
 993
 994                                 <listitem><para>Remove a snapshot
 995                                 previously created with
 996                                 <command>snapshot</command>.</para></listitem>
 997                         </varlistentry>
 998                         <varlistentry>
 999                                 <term><command>daemon-reload</command></term>
1000
1001                                 <listitem><para>Reload systemd manager
1002                                 configuration. This will reload all
1003                                 unit files and recreate the entire
1004                                 dependency tree. While the daemon is
1005                                 reloaded, all sockets systemd listens
1006                                 on on behalf of user configuration will
1007                                 stay accessible.</para> <para>This
1008                                 command should not be confused with
1009                                 the <command>load</command> or
1010                                 <command>reload</command>
1011                                 commands.</para></listitem>
1012                         </varlistentry>
1013                         <varlistentry>
1014                                 <term><command>daemon-reexec</command></term>
1015
1016                                 <listitem><para>Reexecute the systemd
1017                                 manager. This will serialize the
1018                                 manager state, reexecute the process
1019                                 and deserialize the state again. This
1020                                 command is of little use except for
1021                                 debugging and package
1022                                 upgrades. Sometimes it might be
1023                                 helpful as a heavy-weight
1024                                 <command>daemon-reload</command>. While
1025                                 the daemon is reexecuted all sockets
1026                                 systemd listens on on behalf of user
1027                                 configuration will stay
1028                                 accessible.</para></listitem>
1029                         </varlistentry>
1030                         <varlistentry>
1031                                 <term><command>show-environment</command></term>
1032
1033                                 <listitem><para>Dump the systemd
1034                                 manager environment block. The
1035                                 environment block will be dumped in
1036                                 straight-forward form suitable for
1037                                 sourcing into a shell script. This
1038                                 environment block will be passed to
1039                                 all processes the manager
1040                                 spawns.</para></listitem>
1041                         </varlistentry>
1042                         <varlistentry>
1043                                 <term><command>set-environment [NAME=VALUE...]</command></term>
1044
1045                                 <listitem><para>Set one or more
1046                                 systemd manager environment variables,
1047                                 as specified on the command
1048                                 line.</para></listitem>
1049                         </varlistentry>
1050                         <varlistentry>
1051                                 <term><command>unset-environment [NAME...]</command></term>
1052
1053                                 <listitem><para>Unset one or more
1054                                 systemd manager environment
1055                                 variables. If only a variable name is
1056                                 specified it will be removed
1057                                 regardless of its value. If a variable
1058                                 and a value are specified the variable
1059                                 is only removed if it has the
1060                                 specified value.</para></listitem>
1061                         </varlistentry>
1062                         <varlistentry>
1063                                 <term><command>default</command></term>
1064
1065                                 <listitem><para>Enter default
1066                                 mode. This is mostly equivalent to
1067                                 <command>start
1068                                 default.target</command>.</para></listitem>
1069                         </varlistentry>
1070                         <varlistentry>
1071                                 <term><command>rescue</command></term>
1072
1073                                 <listitem><para>Enter rescue
1074                                 mode. This is mostly equivalent to
1075                                 <command>isolate
1076                                 rescue.target</command> but also
1077                                 prints a wall message to all
1078                                 users.</para></listitem>
1079                         </varlistentry>
1080                         <varlistentry>
1081                                 <term><command>emergency</command></term>
1082
1083                                 <listitem><para>Enter emergency
1084                                 mode. This is mostly equivalent to
1085                                 <command>isolate
1086                                 emergency.target</command> but also
1087                                 prints a wall message to all
1088                                 users.</para></listitem>
1089                         </varlistentry>
1090                         <varlistentry>
1091                                 <term><command>halt</command></term>
1092
1093                                 <listitem><para>Shut down and halt the
1094                                 system. This is mostly equivalent to
1095                                 <command>start halt.target</command>
1096                                 but also prints a wall message to all
1097                                 users.  If combined with
1098                                 <option>--force</option> shutdown of
1099                                 all running services is skipped,
1100                                 however all processes are killed and
1101                                 all file systems are unmounted or
1102                                 mounted read-only, immediately
1103                                 followed by the system halt.  If
1104                                 <option>--force</option> is specified
1105                                 twice the the operation is immediately
1106                                 executed without terminating any
1107                                 processes or unmounting any file
1108                                 systems. This may result in data
1109                                 loss.</para></listitem>
1110                         </varlistentry>
1111                         <varlistentry>
1112                                 <term><command>poweroff</command></term>
1113
1114                                 <listitem><para>Shut down and
1115                                 power-off the system. This is mostly
1116                                 equivalent to <command>start
1117                                 poweroff.target</command> but also
1118                                 prints a wall message to all users. If
1119                                 combined with <option>--force</option>
1120                                 shutdown of all running services is
1121                                 skipped, however all processes are
1122                                 killed and all file systems are
1123                                 unmounted or mounted read-only,
1124                                 immediately followed by the powering
1125                                 off. If <option>--force</option> is
1126                                 specified twice the the operation is
1127                                 immediately executed without
1128                                 terminating any processes or
1129                                 unmounting any file systems. This may
1130                                 result in data loss.</para></listitem>
1131                         </varlistentry>
1132                         <varlistentry>
1133                                 <term><command>reboot</command></term>
1134
1135                                 <listitem><para>Shut down and reboot
1136                                 the system. This is mostly equivalent
1137                                 to <command>start
1138                                 reboot.target</command> but also
1139                                 prints a wall message to all users. If
1140                                 combined with <option>--force</option>
1141                                 shutdown of all running services is
1142                                 skipped, however all processes are
1143                                 killed and all file systems are
1144                                 unmounted or mounted read-only,
1145                                 immediately followed by the reboot. If
1146                                 <option>--force</option> is specified
1147                                 twice the the operation is immediately
1148                                 executed without terminating any
1149                                 processes or unmounting any file
1150                                 systems. This may result in data
1151                                 loss.</para></listitem>
1152                         </varlistentry>
1153                         <varlistentry>
1154                                 <term><command>kexec</command></term>
1155
1156                                 <listitem><para>Shut down and reboot
1157                                 the system via kexec. This is mostly
1158                                 equivalent to <command>start
1159                                 kexec.target</command> but also prints
1160                                 a wall message to all users. If
1161                                 combined with <option>--force</option>
1162                                 shutdown of all running services is
1163                                 skipped, however all processes are killed
1164                                 and all file systems are unmounted or
1165                                 mounted read-only, immediately
1166                                 followed by the
1167                                 reboot.</para></listitem>
1168                         </varlistentry>
1169                         <varlistentry>
1170                                 <term><command>exit</command></term>
1171
1172                                 <listitem><para>Ask the systemd
1173                                 manager to quit. This is only
1174                                 supported for user service managers
1175                                 (i.e. in conjunction with the
1176                                 <option>--user</option> option) and
1177                                 will fail otherwise.</para></listitem>
1178                         </varlistentry>
1179                         <varlistentry>
1180                                 <term><command>suspend</command></term>
1181
1182                                 <listitem><para>Suspend the system.</para></listitem>
1183                         </varlistentry>
1184                         <varlistentry>
1185                                 <term><command>hibernate</command></term>
1186
1187                                 <listitem><para>Hibernate the system.</para></listitem>
1188                         </varlistentry>
1189                         <varlistentry>
1190                                 <term><command>switch-root [ROOT] [INIT]</command></term>
1191
1192                                 <listitem><para>Switches to a
1193                                 different root directory and executes
1194                                 a new system manager process below
1195                                 it. This is intended for usage in
1196                                 initial RAM disks ("initrd"), and will
1197                                 transition from the initrd's system
1198                                 manager process (a.k.a "init" process)
1199                                 to the main system manager
1200                                 process. Takes two arguments: the
1201                                 directory to make the new root
1202                                 directory, and the path to the new
1203                                 system manager binary below it to
1204                                 execute as PID 1. If the latter is
1205                                 ommitted or the empty string, a
1206                                 systemd binary will automatically be
1207                                 searched for and used as init. If the
1208                                 system manager path is ommitted or
1209                                 equal the empty string the state of
1210                                 the initrd's system manager process is
1211                                 passed to the main system manager,
1212                                 which allows later introspection of the
1213                                 state of the services involved in the
1214                                 initrd boot.</para></listitem>
1215                         </varlistentry>
1216                 </variablelist>
1217
1218         </refsect1>
1219
1220         <refsect1>
1221                 <title>Exit status</title>
1222
1223                 <para>On success 0 is returned, a non-zero failure
1224                 code otherwise.</para>
1225         </refsect1>
1226
1227         <refsect1>
1228                 <title>Environment</title>
1229
1230                 <variablelist>
1231                         <varlistentry>
1232                                 <term><varname>$SYSTEMD_PAGER</varname></term>
1233                                 <listitem><para>Pager to use when
1234                                 <option>--no-pager</option> is not given;
1235                                 overrides <varname>$PAGER</varname>.  Setting
1236                                 this to an empty string or the value
1237                                 <literal>cat</literal> is equivalent to passing
1238                                 <option>--no-pager</option>.</para></listitem>
1239                         </varlistentry>
1240                 </variablelist>
1241         </refsect1>
1242
1243         <refsect1>
1244                 <title>See Also</title>
1245                 <para>
1246                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1247                         <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1248                         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1249                         <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1250                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1251                         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1252                         <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1253                         <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1254                 </para>
1255         </refsect1>
1256
1257 </refentry>