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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.
8 Copyright 2010 Lennart Poettering
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.
15 systemd is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
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/>.
24 <refentry id="systemctl">
27 <title>systemctl</title>
28 <productname>systemd</productname>
32 <contrib>Developer</contrib>
33 <firstname>Lennart</firstname>
34 <surname>Poettering</surname>
35 <email>lennart@poettering.net</email>
41 <refentrytitle>systemctl</refentrytitle>
42 <manvolnum>1</manvolnum>
46 <refname>systemctl</refname>
47 <refpurpose>Control the systemd system and service manager</refpurpose>
52 <command>systemctl</command>
53 <arg choice="opt" rep="repeat">OPTIONS</arg>
54 <arg choice="plain">COMMAND</arg>
55 <arg choice="opt" rep="repeat">NAME</arg>
60 <title>Description</title>
62 <para><command>systemctl</command> may be used to
63 introspect and control the state of the
64 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
65 system and service manager.</para>
69 <title>Options</title>
71 <para>The following options are understood:</para>
75 <term><option>-h</option></term>
76 <term><option>--help</option></term>
78 <listitem><para>Prints a short help
79 text and exits.</para></listitem>
83 <term><option>--version</option></term>
86 <para>Prints a short version string and exits.</para>
91 <term><option>-t</option></term>
92 <term><option>--type=</option></term>
95 <para>The argument should be a comma-separated list of unit
96 types such as <option>service</option> and
97 <option>socket</option>.
100 <para>If one of the arguments is a unit type, when listing
101 units, limit display to certain unit types. Otherwise, units
102 of all types will be shown.</para>
104 <para>As a special case, if one of the arguments is
105 <option>help</option>, a list of allowed values will be
106 printed and the program will exit.</para>
111 <term><option>--state=</option></term>
114 <para>The argument should be a comma-separated list of unit LOAD,
115 SUB, or ACTIVE states. When listing units, show only those
116 in specified states.</para>
121 <term><option>-p</option></term>
122 <term><option>--property=</option></term>
125 <para>When showing unit/job/manager properties with the
126 <command>show</command> command, limit display to certain
127 properties as specified as argument. If not specified, all
128 set properties are shown. The argument should be a
129 comma-separated list of property names, such as
130 <literal>MainPID</literal>. If specified more than once, all
131 properties with the specified names are shown.</para>
136 <term><option>-a</option></term>
137 <term><option>--all</option></term>
140 <para>When listing units, show all loaded units, regardless
141 of their state, including inactive units. When showing
142 unit/job/manager properties, show all properties regardless
143 whether they are set or not.</para>
144 <para>To list all units installed on the system, use the
145 <command>list-unit-files</command> command instead.</para>
150 <term><option>--reverse</option></term>
153 <para>Show reverse dependencies between units with
154 <command>list-dependencies</command>, i.e. units with
155 dependencies of type <varname>Wants=</varname> or
156 <varname>Requires=</varname> on the given unit.
162 <term><option>--after</option></term>
163 <term><option>--before</option></term>
166 <para>Show which units are started after or before
167 with <command>list-dependencies</command>, respectively.
173 <term><option>-l</option></term>
174 <term><option>--full</option></term>
177 <para>Do not ellipsize unit names, process tree entries, and
178 truncate unit descriptions in the output of
179 <command>list-units</command> and
180 <command>list-jobs</command>.</para>
185 <term><option>--fail</option></term>
188 <para>If the requested operation conflicts with a pending
189 unfinished job, fail the command. If this is not specified,
190 the requested operation will replace the pending job, if
191 necessary. Do not confuse with
192 <option>--failed</option>.</para>
197 <term><option>--show-types</option></term>
200 <para>When showing sockets, show the type of the socket.</para>
205 <term><option>--irreversible</option></term>
208 <para>Mark this transaction's jobs as irreversible. This prevents
209 future conflicting transactions from replacing these jobs.
210 The jobs can still be cancelled using the <command>cancel</command>
216 <term><option>--ignore-dependencies</option></term>
219 <para>When enqueuing a new job, ignore all its dependencies
220 and execute it immediately. If passed, no required units of
221 the unit passed will be pulled in, and no ordering
222 dependencies will be honored. This is mostly a debugging and
223 rescue tool for the administrator and should not be used by
229 <term><option>-i</option></term>
230 <term><option>--ignore-inhibitors</option></term>
233 <para>When system shutdown or a sleep state is requested,
234 ignore inhibitor locks. Applications can establish inhibitor
235 locks to avoid that certain important operations (such as CD
236 burning or suchlike) are interrupted by system shutdown or a
237 sleep state. Any user may take these locks and privileged
238 users may override these locks. If any locks are taken,
239 shutdown and sleep state requests will normally fail
240 (regardless if privileged or not) and a list of active locks
241 is printed. However, if <option>--ignore-inhibitors</option>
242 is specified, the locks are ignored and not printed, and the
243 operation attempted anyway, possibly requiring additional
249 <term><option>-q</option></term>
250 <term><option>--quiet</option></term>
253 <para>Suppress output to standard output in
254 <command>snapshot</command>,
255 <command>is-active</command>,
256 <command>is-failed</command>,
257 <command>enable</command> and
258 <command>disable</command>.</para>
263 <term><option>--no-block</option></term>
266 <para>Do not synchronously wait for the requested operation
267 to finish. If this is not specified, the job will be
268 verified, enqueued and <command>systemctl</command> will
269 wait until it is completed. By passing this argument, it is
270 only verified and enqueued.</para>
275 <term><option>--no-legend</option></term>
278 <para>Do not print a legend, i.e. the column headers and
279 the footer with hints.</para>
284 <term><option>--no-pager</option></term>
287 <para>Do not pipe output into a pager.</para>
292 <term><option>--system</option></term>
295 <para>Talk to the systemd system manager. (Default)</para>
300 <term><option>--user</option></term>
303 <para>Talk to the systemd manager of the calling
309 <term><option>--no-wall</option></term>
312 <para>Do not send wall message before halt, power-off,
318 <term><option>--global</option></term>
321 <para>When used with <command>enable</command> and
322 <command>disable</command>, operate on the global user
323 configuration directory, thus enabling or disabling a unit
324 file globally for all future logins of all users.</para>
329 <term><option>--no-reload</option></term>
332 <para>When used with <command>enable</command> and
333 <command>disable</command>, do not implicitly reload daemon
334 configuration after executing the changes.</para>
339 <term><option>--no-ask-password</option></term>
342 <para>When used with <command>start</command> and related
343 commands, disables asking for passwords. Background services
344 may require input of a password or passphrase string, for
345 example to unlock system hard disks or cryptographic
346 certificates. Unless this option is specified and the
347 command is invoked from a terminal,
348 <command>systemctl</command> will query the user on the
349 terminal for the necessary secrets. Use this option to
350 switch this behavior off. In this case, the password must be
351 supplied by some other means (for example graphical password
352 agents) or the service might fail. This also disables
353 querying the user for authentication for privileged
360 <term><option>--kill-who=</option></term>
363 <para>When used with <command>kill</command>, choose which
364 processes to kill. Must be one of <option>main</option>,
365 <option>control</option> or <option>all</option> to select
366 whether to kill only the main process of the unit, the
367 control process or all processes of the unit. If omitted,
368 defaults to <option>all</option>.</para>
374 <term><option>-s</option></term>
375 <term><option>--signal=</option></term>
378 <para>When used with <command>kill</command>, choose which
379 signal to send to selected processes. Must be one of the
380 well known signal specifiers such as <constant>SIGTERM</constant>, <constant>SIGINT</constant> or
381 <constant>SIGSTOP</constant>. If omitted, defaults to
382 <option>SIGTERM</option>.</para>
387 <term><option>-f</option></term>
388 <term><option>--force</option></term>
391 <para>When used with <command>enable</command>, overwrite
392 any existing conflicting symlinks.</para>
394 <para>When used with <command>halt</command>,
395 <command>poweroff</command>, <command>reboot</command> or
396 <command>kexec</command>, execute the selected operation
397 without shutting down all units. However, all processes will
398 be killed forcibly and all file systems are unmounted or
399 remounted read-only. This is hence a drastic but relatively
400 safe option to request an immediate reboot. If
401 <option>--force</option> is specified twice for these
402 operations, they will be executed immediately without
403 terminating any processes or umounting any file
404 systems. Warning: specifying <option>--force</option> twice
405 with any of these operations might result in data
411 <term><option>--root=</option></term>
415 <command>enable</command>/<command>disable</command>/<command>is-enabled</command>
416 (and related commands), use alternative root path when
417 looking for unit files.</para>
423 <term><option>--runtime</option></term>
426 <para>When used with <command>enable</command>,
427 <command>disable</command>, <command>is-enabled</command>
428 (and related commands), make changes only temporarily, so
429 that they are lost on the next reboot. This will have the
430 effect that changes are not made in subdirectories of
431 <filename>/etc</filename> but in <filename>/run</filename>,
432 with identical immediate effects, however, since the latter
433 is lost on reboot, the changes are lost too.</para>
435 <para>Similar, when used with
436 <command>set-property</command>, make changes only
437 temporarily, so that they are lost on the next
443 <term><option>-H</option></term>
444 <term><option>--host</option></term>
447 <para>Execute operation remotely. Specify a hostname, or
448 username and hostname separated by <literal>@</literal>, to connect to. This
449 will use SSH to talk to the remote systemd
455 <term><option>-P</option></term>
456 <term><option>--privileged</option></term>
459 <para>Acquire privileges via PolicyKit before executing the
465 <term><option>-n</option></term>
466 <term><option>--lines=</option></term>
469 <para>When used with <command>status</command>, controls the
470 number of journal lines to show, counting from the most
471 recent ones. Takes a positive integer argument. Defaults to
477 <term><option>-o</option></term>
478 <term><option>--output=</option></term>
481 <para>When used with <command>status</command>, controls the
482 formatting of the journal entries that are shown. For the
483 available choices, see
484 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
485 Defaults to <literal>short</literal>.</para>
490 <term><option>--plain</option></term>
493 <para>When used with <command>list-dependencies</command>,
494 the output is printed as a list instead of a tree.</para>
502 <title>Commands</title>
504 <para>The following commands are understood:</para>
507 <title>Unit Commands</title>
511 <term><command>list-units</command></term>
514 <para>List known units (subject to limitations specified
515 with <option>-t</option>).</para>
517 <para>This is the default command.</para>
522 <term><command>list-sockets</command></term>
525 <para>List socket units ordered by the listening address. Produces output
528 LISTEN UNIT ACTIVATES
529 /dev/initctl systemd-initctl.socket systemd-initctl.service
531 [::]:22 sshd.socket sshd.service
532 kobject-uevent 1 systemd-udevd-kernel.socket systemd-udevd.service
536 Note: because the addresses might contains spaces, this output
537 is not suitable for programmatic consumption.
540 <para>See also the options <option>--show-types</option>,
541 <option>--all</option>, and <option>--failed</option>.</para>
546 <term><command>start <replaceable>NAME</replaceable>...</command></term>
549 <para>Start (activate) one or more units specified on the
554 <term><command>stop <replaceable>NAME</replaceable>...</command></term>
557 <para>Stop (deactivate) one or more units specified on the
562 <term><command>reload <replaceable>NAME</replaceable>...</command></term>
565 <para>Asks all units listed on the command line to reload
566 their configuration. Note that this will reload the
567 service-specific configuration, not the unit configuration
568 file of systemd. If you want systemd to reload the
569 configuration file of a unit, use the
570 <command>daemon-reload</command> command. In other words:
571 for the example case of Apache, this will reload Apache's
572 <filename>httpd.conf</filename> in the web server, not the
573 <filename>apache.service</filename> systemd unit
576 <para>This command should not be confused with the
577 <command>daemon-reload</command> or <command>load</command>
583 <term><command>restart <replaceable>NAME</replaceable>...</command></term>
586 <para>Restart one or more units specified on the command
587 line. If the units are not running yet, they will be
592 <term><command>try-restart <replaceable>NAME</replaceable>...</command></term>
595 <para>Restart one or more units specified on the command
596 line if the units are running. This does nothing if units are not
597 running. Note that, for compatibility with Red Hat init
598 scripts, <command>condrestart</command> is equivalent to this
603 <term><command>reload-or-restart <replaceable>NAME</replaceable>...</command></term>
606 <para>Reload one or more units if they support it. If not,
607 restart them instead. If the units are not running yet, they
608 will be started.</para>
612 <term><command>reload-or-try-restart <replaceable>NAME</replaceable>...</command></term>
615 <para>Reload one or more units if they support it. If not,
616 restart them instead. This does nothing if the units are not
617 running. Note that, for compatibility with SysV init scripts,
618 <command>force-reload</command> is equivalent to this
623 <term><command>isolate <replaceable>NAME</replaceable></command></term>
626 <para>Start the unit specified on the command line and its
627 dependencies and stop all others.</para>
629 <para>This is similar to changing the runlevel in a
630 traditional init system. The <command>isolate</command>
631 command will immediately stop processes that are not enabled
632 in the new unit, possibly including the graphical
633 environment or terminal you are currently using.</para>
635 <para>Note that this is allowed only on units where
636 <option>AllowIsolate=</option> is enabled. See
637 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
642 <term><command>kill <replaceable>NAME</replaceable>...</command></term>
645 <para>Send a signal to one or more processes of the
646 unit. Use <option>--kill-who=</option> to select which
647 process to kill. Use <option>--kill-mode=</option> to select
648 the kill mode and <option>--signal=</option> to select the
649 signal to send.</para>
653 <term><command>is-active <replaceable>NAME</replaceable>...</command></term>
656 <para>Check whether any of the specified units are active
657 (i.e. running). Returns an exit code 0 if at least one is
658 active, non-zero otherwise. Unless <option>--quiet</option>
659 is specified, this will also print the current unit state to
664 <term><command>is-failed <replaceable>NAME</replaceable>...</command></term>
667 <para>Check whether any of the specified units are in a "failed" state.
668 Returns an exit code 0 if at least one has failed, non-zero
669 otherwise. Unless <option>--quiet</option> is specified, this
670 will also print the current unit state to
675 <term><command>status [<replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...]</command></term>
678 <para>Show terse runtime status information about one or
679 more units, followed by most recent log data from the
680 journal. If no units are specified, show all units (subject
681 to limitations specified with <option>-t</option>). If a PID
682 is passed, show information about the unit the process
685 <para>This function is intended to generate human-readable
686 output. If you are looking for computer-parsable output, use
687 <command>show</command> instead.</para>
691 <term><command>show [<replaceable>NAME</replaceable>...|<replaceable>JOB</replaceable>...]</command></term>
694 <para>Show properties of one or more units, jobs, or the
695 manager itself. If no argument is specified, properties of
696 the manager will be shown. If a unit name is specified,
697 properties of the unit is shown, and if a job id is
698 specified, properties of the job is shown. By default, empty
699 properties are suppressed. Use <option>--all</option> to
700 show those too. To select specific properties to show, use
701 <option>--property=</option>. This command is intended to be
702 used whenever computer-parsable output is required. Use
703 <command>status</command> if you are looking for formatted
704 human-readable output.</para>
709 <term><command>set-property <replaceable>NAME</replaceable> <replaceable>ASSIGNMENT</replaceable>...</command></term>
712 <para>Set the specified unit properties at runtime where
713 this is supported. This allows changing configuration
714 parameter properties such as resource control settings at
715 runtime. Not all properties may be changed at runtime, but
716 many resource control settings (primarily those in
717 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
718 may. The changes are applied instantly, and stored on disk
719 for future boots, unless <option>--runtime</option> is
720 passed, in which case the settings only apply until the
721 next reboot. The syntax of the property assignment follows
722 closely the syntax of assignments in unit files.</para>
724 <para>Example: <command>systemctl set-property foobar.service CPUShares=777</command></para>
726 <para>Note that this command allows changing multiple
727 properties at the same time, which is preferable over
728 setting them individually. Like unit file configuration
729 settings, assigning the empty list to list parameters will
730 reset the list.</para>
735 <term><command>help <replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...</command></term>
738 <para>Show manual pages for one or more units, if
739 available. If a PID is given, the manual pages for the unit
740 the process belongs to are shown.</para>
745 <term><command>reset-failed [<replaceable>NAME</replaceable>...]</command></term>
748 <para>Reset the <literal>failed</literal> state of the
749 specified units, or if no unit name is passed, reset the state of all
750 units. When a unit fails in some way (i.e. process exiting
751 with non-zero error code, terminating abnormally or timing
752 out), it will automatically enter the
753 <literal>failed</literal> state and its exit code and status
754 is recorded for introspection by the administrator until the
755 service is restarted or reset with this command.</para>
760 <term><command>list-dependencies <replaceable>NAME</replaceable></command></term>
763 <para>Shows required and wanted units of the specified
764 unit. If no unit is specified,
765 <filename>default.target</filename> is implied. Target units
766 are recursively expanded. When <option>--all</option> is
767 passed, all other units are recursively expanded as
775 <title>Unit File Commands</title>
779 <term><command>list-unit-files</command></term>
782 <para>List installed unit files.</para>
787 <term><command>enable <replaceable>NAME</replaceable>...</command></term>
790 <para>Enable one or more unit files or unit file instances,
791 as specified on the command line. This will create a number
792 of symlinks as encoded in the <literal>[Install]</literal>
793 sections of the unit files. After the symlinks have been
794 created, the systemd configuration is reloaded (in a way that
795 is equivalent to <command>daemon-reload</command>) to ensure
796 the changes are taken into account immediately. Note that
797 this does <emphasis>not</emphasis> have the effect of also
798 starting any of the units being enabled. If this
799 is desired, a separate <command>start</command> command must
800 be invoked for the unit. Also note that in case of instance
801 enablement, symlinks named the same as instances are created in
802 the install location, however they all point to the same
803 template unit file.</para>
805 <para>This command will print the actions executed. This
806 output may be suppressed by passing <option>--quiet</option>.
809 <para>Note that this operation creates only the suggested
810 symlinks for the units. While this command is the
811 recommended way to manipulate the unit configuration
812 directory, the administrator is free to make additional
813 changes manually by placing or removing symlinks in the
814 directory. This is particularly useful to create
815 configurations that deviate from the suggested default
816 installation. In this case, the administrator must make sure
817 to invoke <command>daemon-reload</command> manually as
818 necessary to ensure the changes are taken into account.
821 <para>Enabling units should not be confused with starting
822 (activating) units, as done by the <command>start</command>
823 command. Enabling and starting units is orthogonal: units
824 may be enabled without being started and started without
825 being enabled. Enabling simply hooks the unit into various
826 suggested places (for example, so that the unit is
827 automatically started on boot or when a particular kind of
828 hardware is plugged in). Starting actually spawns the daemon
829 process (in case of service units), or binds the socket (in
830 case of socket units), and so on.</para>
832 <para>Depending on whether <option>--system</option>,
833 <option>--user</option>, <option>--runtime</option>,
834 or <option>--global</option> is specified, this enables the unit
835 for the system, for the calling user only, for only this boot of
836 the system, or for all future logins of all users, or only this
837 boot. Note that in the last case, no systemd daemon
838 configuration is reloaded.</para>
843 <term><command>disable <replaceable>NAME</replaceable>...</command></term>
846 <para>Disables one or more units. This removes all symlinks
847 to the specified unit files from the unit configuration
848 directory, and hence undoes the changes made by
849 <command>enable</command>. Note however that this removes
850 all symlinks to the unit files (i.e. including manual
851 additions), not just those actually created by
852 <command>enable</command>. This call implicitly reloads the
853 systemd daemon configuration after completing the disabling
854 of the units. Note that this command does not implicitly
855 stop the units that are being disabled. If this is desired,
856 an additional <command>stop</command> command should be
857 executed afterwards.</para>
859 <para>This command will print the actions executed. This
860 output may be suppressed by passing <option>--quiet</option>.
863 <para>This command honors <option>--system</option>,
864 <option>--user</option>, <option>--runtime</option> and
865 <option>--global</option> in a similar way as
866 <command>enable</command>.</para>
871 <term><command>is-enabled <replaceable>NAME</replaceable>...</command></term>
874 <para>Checks whether any of the specified unit files are
875 enabled (as with <command>enable</command>). Returns an exit
876 code of 0 if at least one is enabled, non-zero
877 otherwise. Prints the current enable status. To suppress
878 this output, use <option>--quiet</option>.</para>
883 <term><command>reenable <replaceable>NAME</replaceable>...</command></term>
886 <para>Reenable one or more unit files, as specified on the
887 command line. This is a combination of
888 <command>disable</command> and <command>enable</command> and
889 is useful to reset the symlinks a unit is enabled with to
890 the defaults configured in the <literal>[Install]</literal>
891 section of the unit file.</para>
896 <term><command>preset <replaceable>NAME</replaceable>...</command></term>
899 <para>Reset one or more unit files, as specified on the
900 command line, to the defaults configured in the preset
901 policy files. This has the same effect as
902 <command>disable</command> or <command>enable</command>,
903 depending how the unit is listed in the preset files. For
904 more information on the preset policy format, see
905 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
906 For more information on the concept of presets, please
908 <ulink url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
914 <term><command>mask <replaceable>NAME</replaceable>...</command></term>
917 <para>Mask one or more unit files, as specified on the
918 command line. This will link these units to
919 <filename>/dev/null</filename>, making it impossible to
920 start them. This is a stronger version of
921 <command>disable</command>, since it prohibits all kinds of
922 activation of the unit, including manual activation. Use
923 this option with care. This honors the
924 <option>--runtime</option> option to only mask temporarily
925 until the next reoobt of the system.</para>
930 <term><command>unmask <replaceable>NAME</replaceable>...</command></term>
933 <para>Unmask one or more unit files, as specified on the
934 command line. This will undo the effect of
935 <command>mask</command>.</para>
940 <term><command>link <replaceable>FILENAME</replaceable>...</command></term>
943 <para>Link a unit file that is not in the unit file search
944 paths into the unit file search path. This requires an
945 absolute path to a unit file. The effect of this can be
946 undone with <command>disable</command>. The effect of this
947 command is that a unit file is available for
948 <command>start</command> and other commands although it
949 is not installed directly in the unit search path.</para>
954 <term><command>get-default</command></term>
957 <para>Get the default target specified
958 via <filename>default.target</filename> link.</para>
963 <term><command>set-default <replaceable>NAME</replaceable></command></term>
966 <para>Set the default target to boot into. Command links
967 <filename>default.target</filename> to the given unit.</para>
974 <title>Job Commands</title>
978 <term><command>list-jobs</command></term>
981 <para>List jobs that are in progress.</para>
985 <term><command>cancel <replaceable>JOB</replaceable>...</command></term>
988 <para>Cancel one or more jobs specified on the command line
989 by their numeric job IDs. If no job ID is specified, cancel
990 all pending jobs.</para>
997 <title>Snapshot Commands</title>
1001 <term><command>snapshot [<replaceable>NAME</replaceable>]</command></term>
1004 <para>Create a snapshot. If a snapshot name is specified,
1005 the new snapshot will be named after it. If none is
1006 specified, an automatic snapshot name is generated. In either
1007 case, the snapshot name used is printed to STDOUT, unless
1008 <option>--quiet</option> is specified.</para>
1010 <para>A snapshot refers to a saved state of the systemd
1011 manager. It is implemented itself as a unit that is
1012 generated dynamically with this command and has dependencies
1013 on all units active at the time. At a later time, the user
1014 may return to this state by using the
1015 <command>isolate</command> command on the snapshot unit.
1018 <para>Snapshots are only useful for saving and restoring
1019 which units are running or are stopped, they do not
1020 save/restore any other state. Snapshots are dynamic and lost
1025 <term><command>delete <replaceable>NAME</replaceable>...</command></term>
1028 <para>Remove a snapshot previously created with
1029 <command>snapshot</command>.</para>
1036 <title>Environment Commands</title>
1040 <term><command>show-environment</command></term>
1043 <para>Dump the systemd manager environment block. The
1044 environment block will be dumped in straight-forward form
1045 suitable for sourcing into a shell script. This environment
1046 block will be passed to all processes the manager
1051 <term><command>set-environment <replaceable>VARIABLE=VALUE</replaceable>...</command></term>
1054 <para>Set one or more systemd manager environment variables,
1055 as specified on the command line.</para>
1059 <term><command>unset-environment <replaceable>VARIABLE</replaceable>...</command></term>
1062 <para>Unset one or more systemd manager environment
1063 variables. If only a variable name is specified, it will be
1064 removed regardless of its value. If a variable and a value
1065 are specified, the variable is only removed if it has the
1066 specified value.</para>
1073 <title>Manager Lifecycle Commands</title>
1077 <term><command>daemon-reload</command></term>
1080 <para>Reload systemd manager configuration. This will reload
1081 all unit files and recreate the entire dependency
1082 tree. While the daemon is being reloaded, all sockets systemd
1083 listens on on behalf of user configuration will stay
1084 accessible.</para> <para>This command should not be confused
1085 with the <command>load</command> or
1086 <command>reload</command> commands.</para>
1090 <term><command>daemon-reexec</command></term>
1093 <para>Reexecute the systemd manager. This will serialize the
1094 manager state, reexecute the process and deserialize the
1095 state again. This command is of little use except for
1096 debugging and package upgrades. Sometimes, it might be
1097 helpful as a heavy-weight <command>daemon-reload</command>.
1098 While the daemon is being reexecuted, all sockets systemd listening
1099 on behalf of user configuration will stay accessible.
1107 <title>System Commands</title>
1111 <term><command>default</command></term>
1114 <para>Enter default mode. This is mostly equivalent to
1115 <command>isolate default.target</command>.</para>
1119 <term><command>rescue</command></term>
1122 <para>Enter rescue mode. This is mostly equivalent to
1123 <command>isolate rescue.target</command>, but also prints a
1124 wall message to all users.</para>
1128 <term><command>emergency</command></term>
1131 <para>Enter emergency mode. This is mostly equivalent to
1132 <command>isolate emergency.target</command>, but also prints
1133 a wall message to all users.</para>
1137 <term><command>halt</command></term>
1140 <para>Shut down and halt the system. This is mostly equivalent to
1141 <command>start halt.target --irreversible</command>, but also
1142 prints a wall message to all users. If combined with
1143 <option>--force</option>, shutdown of all running services is
1144 skipped, however all processes are killed and all file
1145 systems are unmounted or mounted read-only, immediately
1146 followed by the system halt. If <option>--force</option> is
1147 specified twice, the operation is immediately executed
1148 without terminating any processes or unmounting any file
1149 systems. This may result in data loss.</para>
1153 <term><command>poweroff</command></term>
1156 <para>Shut down and power-off the system. This is mostly
1157 equivalent to <command>start poweroff.target --irreversible</command>,
1158 but also prints a wall message to all users. If combined with
1159 <option>--force</option>, shutdown of all running services is
1160 skipped, however all processes are killed and all file
1161 systems are unmounted or mounted read-only, immediately
1162 followed by the powering off. If <option>--force</option> is
1163 specified twice, the operation is immediately executed
1164 without terminating any processes or unmounting any file
1165 systems. This may result in data loss.</para>
1169 <term><command>reboot</command></term>
1172 <para>Shut down and reboot the system. This is mostly
1173 equivalent to <command>start reboot.target --irreversible</command>,
1174 but also prints a wall message to all users. If combined with
1175 <option>--force</option>, shutdown of all running services is
1176 skipped, however all processes are killed and all file
1177 systems are unmounted or mounted read-only, immediately
1178 followed by the reboot. If <option>--force</option> is
1179 specified twice, the operation is immediately executed
1180 without terminating any processes or unmounting any file
1181 systems. This may result in data loss.</para>
1185 <term><command>kexec</command></term>
1188 <para>Shut down and reboot the system via kexec. This is
1189 mostly equivalent to <command>start kexec.target --irreversible</command>,
1190 but also prints a wall message to all users. If combined
1191 with <option>--force</option>, shutdown of all running
1192 services is skipped, however all processes are killed and
1193 all file systems are unmounted or mounted read-only,
1194 immediately followed by the reboot.</para>
1198 <term><command>exit</command></term>
1201 <para>Ask the systemd manager to quit. This is only
1202 supported for user service managers (i.e. in conjunction
1203 with the <option>--user</option> option) and will fail
1209 <term><command>suspend</command></term>
1212 <para>Suspend the system. This will trigger activation of
1213 the special <filename>suspend.target</filename> target.
1218 <term><command>hibernate</command></term>
1221 <para>Hibernate the system. This will trigger activation of
1222 the special <filename>hibernate.target</filename> target.
1227 <term><command>hybrid-sleep</command></term>
1230 <para>Hibernate and suspend the system. This will trigger
1231 activation of the special
1232 <filename>hybrid-sleep.target</filename> target.</para>
1236 <term><command>switch-root <replaceable>ROOT</replaceable> [<replaceable>INIT</replaceable>]</command></term>
1239 <para>Switches to a different root directory and executes a
1240 new system manager process below it. This is intended for
1241 usage in initial RAM disks ("initrd"), and will transition
1242 from the initrd's system manager process (a.k.a "init"
1243 process) to the main system manager process. This call takes two
1244 arguments: the directory that is to become the new root directory, and
1245 the path to the new system manager binary below it to
1246 execute as PID 1. If the latter is omitted or the empty
1247 string, a systemd binary will automatically be searched for
1248 and used as init. If the system manager path is omitted or
1249 equal to the empty string, the state of the initrd's system
1250 manager process is passed to the main system manager, which
1251 allows later introspection of the state of the services
1252 involved in the initrd boot.</para>
1261 <title>Exit status</title>
1263 <para>On success, 0 is returned, a non-zero failure
1264 code otherwise.</para>
1268 <title>Environment</title>
1270 <variablelist class='environment-variables'>
1272 <term><varname>$SYSTEMD_PAGER</varname></term>
1275 <para>Pager to use when <option>--no-pager</option> is not
1276 given; overrides <varname>$PAGER</varname>. Setting this to
1277 an empty string or the value <literal>cat</literal> is
1278 equivalent to passing
1279 <option>--no-pager</option>.</para>
1286 <title>See Also</title>
1288 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1289 <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1290 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1291 <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1292 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1293 <citerefentry><refentrytitle>systemd.resource-management</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1294 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1295 <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1296 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>