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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>
67 <para>For Unit Commands the <replaceable>NAME</replaceable> represents full name of unit.
69 systemctl start foo.service
71 For Unit File Commands the <replaceable>NAME</replaceable> represents full name of the unit file, or absolute path to the unit file.
73 systemctl start /path/to/foo.service
75 While working with services/service files, <command>systemctl</command> is able to append .service suffix when it is missing.
78 </programlisting></para>
82 <title>Options</title>
84 <para>The following options are understood:</para>
88 <term><option>-h</option></term>
89 <term><option>--help</option></term>
91 <listitem><para>Prints a short help
92 text and exits.</para></listitem>
96 <term><option>--version</option></term>
99 <para>Prints a short version string and exits.</para>
104 <term><option>-t</option></term>
105 <term><option>--type=</option></term>
108 <para>The argument should be a comma-separated list of unit
109 types such as <option>service</option> and
110 <option>socket</option>.
113 <para>If one of the arguments is a unit type, when listing
114 units, limit display to certain unit types. Otherwise, units
115 of all types will be shown.</para>
117 <para>As a special case, if one of the arguments is
118 <option>help</option>, a list of allowed values will be
119 printed and the program will exit.</para>
124 <term><option>--state=</option></term>
127 <para>The argument should be a comma-separated list of unit LOAD,
128 SUB, or ACTIVE states. When listing units, show only those
129 in specified states.</para>
134 <term><option>-p</option></term>
135 <term><option>--property=</option></term>
138 <para>When showing unit/job/manager properties with the
139 <command>show</command> command, limit display to certain
140 properties as specified as argument. If not specified, all
141 set properties are shown. The argument should be a
142 comma-separated list of property names, such as
143 <literal>MainPID</literal>. If specified more than once, all
144 properties with the specified names are shown.</para>
149 <term><option>-a</option></term>
150 <term><option>--all</option></term>
153 <para>When listing units, show all loaded units, regardless
154 of their state, including inactive units. When showing
155 unit/job/manager properties, show all properties regardless
156 whether they are set or not.</para>
157 <para>To list all units installed on the system, use the
158 <command>list-unit-files</command> command instead.</para>
163 <term><option>--reverse</option></term>
166 <para>Show reverse dependencies between units with
167 <command>list-dependencies</command>, i.e. units with
168 dependencies of type <varname>Wants=</varname> or
169 <varname>Requires=</varname> on the given unit.
175 <term><option>--after</option></term>
176 <term><option>--before</option></term>
179 <para>Show which units are started after or before
180 with <command>list-dependencies</command>, respectively.
186 <term><option>-l</option></term>
187 <term><option>--full</option></term>
190 <para>Do not ellipsize unit names, process tree entries, and
191 truncate unit descriptions in the output of
192 <command>list-units</command> and
193 <command>list-jobs</command>.</para>
198 <term><option>--fail</option></term>
201 <para>If the requested operation conflicts with a pending
202 unfinished job, fail the command. If this is not specified,
203 the requested operation will replace the pending job, if
204 necessary. Do not confuse with
205 <option>--failed</option>.</para>
210 <term><option>--show-types</option></term>
213 <para>When showing sockets, show the type of the socket.</para>
218 <term><option>--irreversible</option></term>
221 <para>Mark this transaction's jobs as irreversible. This prevents
222 future conflicting transactions from replacing these jobs.
223 The jobs can still be cancelled using the <command>cancel</command>
229 <term><option>--ignore-dependencies</option></term>
232 <para>When enqueuing a new job, ignore all its dependencies
233 and execute it immediately. If passed, no required units of
234 the unit passed will be pulled in, and no ordering
235 dependencies will be honored. This is mostly a debugging and
236 rescue tool for the administrator and should not be used by
242 <term><option>-i</option></term>
243 <term><option>--ignore-inhibitors</option></term>
246 <para>When system shutdown or a sleep state is requested,
247 ignore inhibitor locks. Applications can establish inhibitor
248 locks to avoid that certain important operations (such as CD
249 burning or suchlike) are interrupted by system shutdown or a
250 sleep state. Any user may take these locks and privileged
251 users may override these locks. If any locks are taken,
252 shutdown and sleep state requests will normally fail
253 (regardless if privileged or not) and a list of active locks
254 is printed. However, if <option>--ignore-inhibitors</option>
255 is specified, the locks are ignored and not printed, and the
256 operation attempted anyway, possibly requiring additional
262 <term><option>-q</option></term>
263 <term><option>--quiet</option></term>
266 <para>Suppress output to standard output in
267 <command>snapshot</command>,
268 <command>is-active</command>,
269 <command>is-failed</command>,
270 <command>enable</command> and
271 <command>disable</command>.</para>
276 <term><option>--no-block</option></term>
279 <para>Do not synchronously wait for the requested operation
280 to finish. If this is not specified, the job will be
281 verified, enqueued and <command>systemctl</command> will
282 wait until it is completed. By passing this argument, it is
283 only verified and enqueued.</para>
288 <term><option>--no-legend</option></term>
291 <para>Do not print a legend, i.e. the column headers and
292 the footer with hints.</para>
297 <term><option>--no-pager</option></term>
300 <para>Do not pipe output into a pager.</para>
305 <term><option>--system</option></term>
308 <para>Talk to the systemd system manager. (Default)</para>
313 <term><option>--user</option></term>
316 <para>Talk to the systemd manager of the calling
322 <term><option>--no-wall</option></term>
325 <para>Do not send wall message before halt, power-off,
331 <term><option>--global</option></term>
334 <para>When used with <command>enable</command> and
335 <command>disable</command>, operate on the global user
336 configuration directory, thus enabling or disabling a unit
337 file globally for all future logins of all users.</para>
342 <term><option>--no-reload</option></term>
345 <para>When used with <command>enable</command> and
346 <command>disable</command>, do not implicitly reload daemon
347 configuration after executing the changes.</para>
352 <term><option>--no-ask-password</option></term>
355 <para>When used with <command>start</command> and related
356 commands, disables asking for passwords. Background services
357 may require input of a password or passphrase string, for
358 example to unlock system hard disks or cryptographic
359 certificates. Unless this option is specified and the
360 command is invoked from a terminal,
361 <command>systemctl</command> will query the user on the
362 terminal for the necessary secrets. Use this option to
363 switch this behavior off. In this case, the password must be
364 supplied by some other means (for example graphical password
365 agents) or the service might fail. This also disables
366 querying the user for authentication for privileged
373 <term><option>--kill-who=</option></term>
376 <para>When used with <command>kill</command>, choose which
377 processes to kill. Must be one of <option>main</option>,
378 <option>control</option> or <option>all</option> to select
379 whether to kill only the main process of the unit, the
380 control process or all processes of the unit. If omitted,
381 defaults to <option>all</option>.</para>
387 <term><option>-s</option></term>
388 <term><option>--signal=</option></term>
391 <para>When used with <command>kill</command>, choose which
392 signal to send to selected processes. Must be one of the
393 well known signal specifiers such as <constant>SIGTERM</constant>, <constant>SIGINT</constant> or
394 <constant>SIGSTOP</constant>. If omitted, defaults to
395 <option>SIGTERM</option>.</para>
400 <term><option>-f</option></term>
401 <term><option>--force</option></term>
404 <para>When used with <command>enable</command>, overwrite
405 any existing conflicting symlinks.</para>
407 <para>When used with <command>halt</command>,
408 <command>poweroff</command>, <command>reboot</command> or
409 <command>kexec</command>, execute the selected operation
410 without shutting down all units. However, all processes will
411 be killed forcibly and all file systems are unmounted or
412 remounted read-only. This is hence a drastic but relatively
413 safe option to request an immediate reboot. If
414 <option>--force</option> is specified twice for these
415 operations, they will be executed immediately without
416 terminating any processes or umounting any file
417 systems. Warning: specifying <option>--force</option> twice
418 with any of these operations might result in data
424 <term><option>--root=</option></term>
428 <command>enable</command>/<command>disable</command>/<command>is-enabled</command>
429 (and related commands), use alternative root path when
430 looking for unit files.</para>
436 <term><option>--runtime</option></term>
439 <para>When used with <command>enable</command>,
440 <command>disable</command>, <command>is-enabled</command>
441 (and related commands), make changes only temporarily, so
442 that they are lost on the next reboot. This will have the
443 effect that changes are not made in subdirectories of
444 <filename>/etc</filename> but in <filename>/run</filename>,
445 with identical immediate effects, however, since the latter
446 is lost on reboot, the changes are lost too.</para>
448 <para>Similar, when used with
449 <command>set-property</command>, make changes only
450 temporarily, so that they are lost on the next
456 <term><option>-H</option></term>
457 <term><option>--host</option></term>
460 <para>Execute operation remotely. Specify a hostname, or
461 username and hostname separated by <literal>@</literal>, to connect to. This
462 will use SSH to talk to the remote systemd
468 <term><option>-P</option></term>
469 <term><option>--privileged</option></term>
472 <para>Acquire privileges via PolicyKit before executing the
478 <term><option>-n</option></term>
479 <term><option>--lines=</option></term>
482 <para>When used with <command>status</command>, controls the
483 number of journal lines to show, counting from the most
484 recent ones. Takes a positive integer argument. Defaults to
490 <term><option>-o</option></term>
491 <term><option>--output=</option></term>
494 <para>When used with <command>status</command>, controls the
495 formatting of the journal entries that are shown. For the
496 available choices, see
497 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
498 Defaults to <literal>short</literal>.</para>
503 <term><option>--plain</option></term>
506 <para>When used with <command>list-dependencies</command>,
507 the output is printed as a list instead of a tree.</para>
515 <title>Commands</title>
517 <para>The following commands are understood:</para>
520 <title>Unit Commands</title>
524 <term><command>list-units</command></term>
527 <para>List known units (subject to limitations specified
528 with <option>-t</option>).</para>
530 <para>This is the default command.</para>
535 <term><command>list-sockets</command></term>
538 <para>List socket units ordered by the listening address. Produces output
541 LISTEN UNIT ACTIVATES
542 /dev/initctl systemd-initctl.socket systemd-initctl.service
544 [::]:22 sshd.socket sshd.service
545 kobject-uevent 1 systemd-udevd-kernel.socket systemd-udevd.service
549 Note: because the addresses might contains spaces, this output
550 is not suitable for programmatic consumption.
553 <para>See also the options <option>--show-types</option>,
554 <option>--all</option>, and <option>--failed</option>.</para>
559 <term><command>start <replaceable>NAME</replaceable>...</command></term>
562 <para>Start (activate) one or more units specified on the
567 <term><command>stop <replaceable>NAME</replaceable>...</command></term>
570 <para>Stop (deactivate) one or more units specified on the
575 <term><command>reload <replaceable>NAME</replaceable>...</command></term>
578 <para>Asks all units listed on the command line to reload
579 their configuration. Note that this will reload the
580 service-specific configuration, not the unit configuration
581 file of systemd. If you want systemd to reload the
582 configuration file of a unit, use the
583 <command>daemon-reload</command> command. In other words:
584 for the example case of Apache, this will reload Apache's
585 <filename>httpd.conf</filename> in the web server, not the
586 <filename>apache.service</filename> systemd unit
589 <para>This command should not be confused with the
590 <command>daemon-reload</command> or <command>load</command>
596 <term><command>restart <replaceable>NAME</replaceable>...</command></term>
599 <para>Restart one or more units specified on the command
600 line. If the units are not running yet, they will be
605 <term><command>try-restart <replaceable>NAME</replaceable>...</command></term>
608 <para>Restart one or more units specified on the command
609 line if the units are running. This does nothing if units are not
610 running. Note that, for compatibility with Red Hat init
611 scripts, <command>condrestart</command> is equivalent to this
616 <term><command>reload-or-restart <replaceable>NAME</replaceable>...</command></term>
619 <para>Reload one or more units if they support it. If not,
620 restart them instead. If the units are not running yet, they
621 will be started.</para>
625 <term><command>reload-or-try-restart <replaceable>NAME</replaceable>...</command></term>
628 <para>Reload one or more units if they support it. If not,
629 restart them instead. This does nothing if the units are not
630 running. Note that, for compatibility with SysV init scripts,
631 <command>force-reload</command> is equivalent to this
636 <term><command>isolate <replaceable>NAME</replaceable></command></term>
639 <para>Start the unit specified on the command line and its
640 dependencies and stop all others.</para>
642 <para>This is similar to changing the runlevel in a
643 traditional init system. The <command>isolate</command>
644 command will immediately stop processes that are not enabled
645 in the new unit, possibly including the graphical
646 environment or terminal you are currently using.</para>
648 <para>Note that this is allowed only on units where
649 <option>AllowIsolate=</option> is enabled. See
650 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
655 <term><command>kill <replaceable>NAME</replaceable>...</command></term>
658 <para>Send a signal to one or more processes of the
659 unit. Use <option>--kill-who=</option> to select which
660 process to kill. Use <option>--kill-mode=</option> to select
661 the kill mode and <option>--signal=</option> to select the
662 signal to send.</para>
666 <term><command>is-active <replaceable>NAME</replaceable>...</command></term>
669 <para>Check whether any of the specified units are active
670 (i.e. running). Returns an exit code 0 if at least one is
671 active, non-zero otherwise. Unless <option>--quiet</option>
672 is specified, this will also print the current unit state to
677 <term><command>is-failed <replaceable>NAME</replaceable>...</command></term>
680 <para>Check whether any of the specified units are in a "failed" state.
681 Returns an exit code 0 if at least one has failed, non-zero
682 otherwise. Unless <option>--quiet</option> is specified, this
683 will also print the current unit state to
688 <term><command>status [<replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...]</command></term>
691 <para>Show terse runtime status information about one or
692 more units, followed by most recent log data from the
693 journal. If no units are specified, show all units (subject
694 to limitations specified with <option>-t</option>). If a PID
695 is passed, show information about the unit the process
698 <para>This function is intended to generate human-readable
699 output. If you are looking for computer-parsable output, use
700 <command>show</command> instead.</para>
704 <term><command>show [<replaceable>NAME</replaceable>...|<replaceable>JOB</replaceable>...]</command></term>
707 <para>Show properties of one or more units, jobs, or the
708 manager itself. If no argument is specified, properties of
709 the manager will be shown. If a unit name is specified,
710 properties of the unit is shown, and if a job id is
711 specified, properties of the job is shown. By default, empty
712 properties are suppressed. Use <option>--all</option> to
713 show those too. To select specific properties to show, use
714 <option>--property=</option>. This command is intended to be
715 used whenever computer-parsable output is required. Use
716 <command>status</command> if you are looking for formatted
717 human-readable output.</para>
722 <term><command>set-property <replaceable>NAME</replaceable> <replaceable>ASSIGNMENT</replaceable>...</command></term>
725 <para>Set the specified unit properties at runtime where
726 this is supported. This allows changing configuration
727 parameter properties such as resource control settings at
728 runtime. Not all properties may be changed at runtime, but
729 many resource control settings (primarily those in
730 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
731 may. The changes are applied instantly, and stored on disk
732 for future boots, unless <option>--runtime</option> is
733 passed, in which case the settings only apply until the
734 next reboot. The syntax of the property assignment follows
735 closely the syntax of assignments in unit files.</para>
737 <para>Example: <command>systemctl set-property foobar.service CPUShares=777</command></para>
739 <para>Note that this command allows changing multiple
740 properties at the same time, which is preferable over
741 setting them individually. Like unit file configuration
742 settings, assigning the empty list to list parameters will
743 reset the list.</para>
748 <term><command>help <replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...</command></term>
751 <para>Show manual pages for one or more units, if
752 available. If a PID is given, the manual pages for the unit
753 the process belongs to are shown.</para>
758 <term><command>reset-failed [<replaceable>NAME</replaceable>...]</command></term>
761 <para>Reset the <literal>failed</literal> state of the
762 specified units, or if no unit name is passed, reset the state of all
763 units. When a unit fails in some way (i.e. process exiting
764 with non-zero error code, terminating abnormally or timing
765 out), it will automatically enter the
766 <literal>failed</literal> state and its exit code and status
767 is recorded for introspection by the administrator until the
768 service is restarted or reset with this command.</para>
773 <term><command>list-dependencies <replaceable>NAME</replaceable></command></term>
776 <para>Shows required and wanted units of the specified
777 unit. If no unit is specified,
778 <filename>default.target</filename> is implied. Target units
779 are recursively expanded. When <option>--all</option> is
780 passed, all other units are recursively expanded as
788 <title>Unit File Commands</title>
792 <term><command>list-unit-files</command></term>
795 <para>List installed unit files.</para>
800 <term><command>enable <replaceable>NAME</replaceable>...</command></term>
803 <para>Enable one or more unit files or unit file instances,
804 as specified on the command line. This will create a number
805 of symlinks as encoded in the <literal>[Install]</literal>
806 sections of the unit files. After the symlinks have been
807 created, the systemd configuration is reloaded (in a way that
808 is equivalent to <command>daemon-reload</command>) to ensure
809 the changes are taken into account immediately. Note that
810 this does <emphasis>not</emphasis> have the effect of also
811 starting any of the units being enabled. If this
812 is desired, a separate <command>start</command> command must
813 be invoked for the unit. Also note that in case of instance
814 enablement, symlinks named the same as instances are created in
815 the install location, however they all point to the same
816 template unit file.</para>
818 <para>This command will print the actions executed. This
819 output may be suppressed by passing <option>--quiet</option>.
822 <para>Note that this operation creates only the suggested
823 symlinks for the units. While this command is the
824 recommended way to manipulate the unit configuration
825 directory, the administrator is free to make additional
826 changes manually by placing or removing symlinks in the
827 directory. This is particularly useful to create
828 configurations that deviate from the suggested default
829 installation. In this case, the administrator must make sure
830 to invoke <command>daemon-reload</command> manually as
831 necessary to ensure the changes are taken into account.
834 <para>Enabling units should not be confused with starting
835 (activating) units, as done by the <command>start</command>
836 command. Enabling and starting units is orthogonal: units
837 may be enabled without being started and started without
838 being enabled. Enabling simply hooks the unit into various
839 suggested places (for example, so that the unit is
840 automatically started on boot or when a particular kind of
841 hardware is plugged in). Starting actually spawns the daemon
842 process (in case of service units), or binds the socket (in
843 case of socket units), and so on.</para>
845 <para>Depending on whether <option>--system</option>,
846 <option>--user</option>, <option>--runtime</option>,
847 or <option>--global</option> is specified, this enables the unit
848 for the system, for the calling user only, for only this boot of
849 the system, or for all future logins of all users, or only this
850 boot. Note that in the last case, no systemd daemon
851 configuration is reloaded.</para>
856 <term><command>disable <replaceable>NAME</replaceable>...</command></term>
859 <para>Disables one or more units. This removes all symlinks
860 to the specified unit files from the unit configuration
861 directory, and hence undoes the changes made by
862 <command>enable</command>. Note however that this removes
863 all symlinks to the unit files (i.e. including manual
864 additions), not just those actually created by
865 <command>enable</command>. This call implicitly reloads the
866 systemd daemon configuration after completing the disabling
867 of the units. Note that this command does not implicitly
868 stop the units that are being disabled. If this is desired,
869 an additional <command>stop</command> command should be
870 executed afterwards.</para>
872 <para>This command will print the actions executed. This
873 output may be suppressed by passing <option>--quiet</option>.
876 <para>This command honors <option>--system</option>,
877 <option>--user</option>, <option>--runtime</option> and
878 <option>--global</option> in a similar way as
879 <command>enable</command>.</para>
884 <term><command>is-enabled <replaceable>NAME</replaceable>...</command></term>
887 <para>Checks whether any of the specified unit files are
888 enabled (as with <command>enable</command>). Returns an exit
889 code of 0 if at least one is enabled, non-zero
890 otherwise. Prints the current enable status. To suppress
891 this output, use <option>--quiet</option>.</para>
896 <term><command>reenable <replaceable>NAME</replaceable>...</command></term>
899 <para>Reenable one or more unit files, as specified on the
900 command line. This is a combination of
901 <command>disable</command> and <command>enable</command> and
902 is useful to reset the symlinks a unit is enabled with to
903 the defaults configured in the <literal>[Install]</literal>
904 section of the unit file.</para>
909 <term><command>preset <replaceable>NAME</replaceable>...</command></term>
912 <para>Reset one or more unit files, as specified on the
913 command line, to the defaults configured in the preset
914 policy files. This has the same effect as
915 <command>disable</command> or <command>enable</command>,
916 depending how the unit is listed in the preset files. For
917 more information on the preset policy format, see
918 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
919 For more information on the concept of presets, please
921 <ulink url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
927 <term><command>mask <replaceable>NAME</replaceable>...</command></term>
930 <para>Mask one or more unit files, as specified on the
931 command line. This will link these units to
932 <filename>/dev/null</filename>, making it impossible to
933 start them. This is a stronger version of
934 <command>disable</command>, since it prohibits all kinds of
935 activation of the unit, including manual activation. Use
936 this option with care. This honors the
937 <option>--runtime</option> option to only mask temporarily
938 until the next reoobt of the system.</para>
943 <term><command>unmask <replaceable>NAME</replaceable>...</command></term>
946 <para>Unmask one or more unit files, as specified on the
947 command line. This will undo the effect of
948 <command>mask</command>.</para>
953 <term><command>link <replaceable>FILENAME</replaceable>...</command></term>
956 <para>Link a unit file that is not in the unit file search
957 paths into the unit file search path. This requires an
958 absolute path to a unit file. The effect of this can be
959 undone with <command>disable</command>. The effect of this
960 command is that a unit file is available for
961 <command>start</command> and other commands although it
962 is not installed directly in the unit search path.</para>
967 <term><command>get-default</command></term>
970 <para>Get the default target specified
971 via <filename>default.target</filename> link.</para>
976 <term><command>set-default <replaceable>NAME</replaceable></command></term>
979 <para>Set the default target to boot into. Command links
980 <filename>default.target</filename> to the given unit.</para>
987 <title>Job Commands</title>
991 <term><command>list-jobs</command></term>
994 <para>List jobs that are in progress.</para>
998 <term><command>cancel <replaceable>JOB</replaceable>...</command></term>
1001 <para>Cancel one or more jobs specified on the command line
1002 by their numeric job IDs. If no job ID is specified, cancel
1003 all pending jobs.</para>
1010 <title>Snapshot Commands</title>
1014 <term><command>snapshot [<replaceable>NAME</replaceable>]</command></term>
1017 <para>Create a snapshot. If a snapshot name is specified,
1018 the new snapshot will be named after it. If none is
1019 specified, an automatic snapshot name is generated. In either
1020 case, the snapshot name used is printed to STDOUT, unless
1021 <option>--quiet</option> is specified.</para>
1023 <para>A snapshot refers to a saved state of the systemd
1024 manager. It is implemented itself as a unit that is
1025 generated dynamically with this command and has dependencies
1026 on all units active at the time. At a later time, the user
1027 may return to this state by using the
1028 <command>isolate</command> command on the snapshot unit.
1031 <para>Snapshots are only useful for saving and restoring
1032 which units are running or are stopped, they do not
1033 save/restore any other state. Snapshots are dynamic and lost
1038 <term><command>delete <replaceable>NAME</replaceable>...</command></term>
1041 <para>Remove a snapshot previously created with
1042 <command>snapshot</command>.</para>
1049 <title>Environment Commands</title>
1053 <term><command>show-environment</command></term>
1056 <para>Dump the systemd manager environment block. The
1057 environment block will be dumped in straight-forward form
1058 suitable for sourcing into a shell script. This environment
1059 block will be passed to all processes the manager
1064 <term><command>set-environment <replaceable>VARIABLE=VALUE</replaceable>...</command></term>
1067 <para>Set one or more systemd manager environment variables,
1068 as specified on the command line.</para>
1072 <term><command>unset-environment <replaceable>VARIABLE</replaceable>...</command></term>
1075 <para>Unset one or more systemd manager environment
1076 variables. If only a variable name is specified, it will be
1077 removed regardless of its value. If a variable and a value
1078 are specified, the variable is only removed if it has the
1079 specified value.</para>
1086 <title>Manager Lifecycle Commands</title>
1090 <term><command>daemon-reload</command></term>
1093 <para>Reload systemd manager configuration. This will reload
1094 all unit files and recreate the entire dependency
1095 tree. While the daemon is being reloaded, all sockets systemd
1096 listens on on behalf of user configuration will stay
1097 accessible.</para> <para>This command should not be confused
1098 with the <command>load</command> or
1099 <command>reload</command> commands.</para>
1103 <term><command>daemon-reexec</command></term>
1106 <para>Reexecute the systemd manager. This will serialize the
1107 manager state, reexecute the process and deserialize the
1108 state again. This command is of little use except for
1109 debugging and package upgrades. Sometimes, it might be
1110 helpful as a heavy-weight <command>daemon-reload</command>.
1111 While the daemon is being reexecuted, all sockets systemd listening
1112 on behalf of user configuration will stay accessible.
1120 <title>System Commands</title>
1124 <term><command>default</command></term>
1127 <para>Enter default mode. This is mostly equivalent to
1128 <command>isolate default.target</command>.</para>
1132 <term><command>rescue</command></term>
1135 <para>Enter rescue mode. This is mostly equivalent to
1136 <command>isolate rescue.target</command>, but also prints a
1137 wall message to all users.</para>
1141 <term><command>emergency</command></term>
1144 <para>Enter emergency mode. This is mostly equivalent to
1145 <command>isolate emergency.target</command>, but also prints
1146 a wall message to all users.</para>
1150 <term><command>halt</command></term>
1153 <para>Shut down and halt the system. This is mostly equivalent to
1154 <command>start halt.target --irreversible</command>, but also
1155 prints a wall message to all users. If combined with
1156 <option>--force</option>, shutdown of all running services is
1157 skipped, however all processes are killed and all file
1158 systems are unmounted or mounted read-only, immediately
1159 followed by the system halt. If <option>--force</option> is
1160 specified twice, the operation is immediately executed
1161 without terminating any processes or unmounting any file
1162 systems. This may result in data loss.</para>
1166 <term><command>poweroff</command></term>
1169 <para>Shut down and power-off the system. This is mostly
1170 equivalent to <command>start poweroff.target --irreversible</command>,
1171 but also prints a wall message to all users. If combined with
1172 <option>--force</option>, shutdown of all running services is
1173 skipped, however all processes are killed and all file
1174 systems are unmounted or mounted read-only, immediately
1175 followed by the powering off. If <option>--force</option> is
1176 specified twice, the operation is immediately executed
1177 without terminating any processes or unmounting any file
1178 systems. This may result in data loss.</para>
1182 <term><command>reboot</command></term>
1185 <para>Shut down and reboot the system. This is mostly
1186 equivalent to <command>start reboot.target --irreversible</command>,
1187 but also prints a wall message to all users. If combined with
1188 <option>--force</option>, shutdown of all running services is
1189 skipped, however all processes are killed and all file
1190 systems are unmounted or mounted read-only, immediately
1191 followed by the reboot. If <option>--force</option> is
1192 specified twice, the operation is immediately executed
1193 without terminating any processes or unmounting any file
1194 systems. This may result in data loss.</para>
1198 <term><command>kexec</command></term>
1201 <para>Shut down and reboot the system via kexec. This is
1202 mostly equivalent to <command>start kexec.target --irreversible</command>,
1203 but also prints a wall message to all users. If combined
1204 with <option>--force</option>, shutdown of all running
1205 services is skipped, however all processes are killed and
1206 all file systems are unmounted or mounted read-only,
1207 immediately followed by the reboot.</para>
1211 <term><command>exit</command></term>
1214 <para>Ask the systemd manager to quit. This is only
1215 supported for user service managers (i.e. in conjunction
1216 with the <option>--user</option> option) and will fail
1222 <term><command>suspend</command></term>
1225 <para>Suspend the system. This will trigger activation of
1226 the special <filename>suspend.target</filename> target.
1231 <term><command>hibernate</command></term>
1234 <para>Hibernate the system. This will trigger activation of
1235 the special <filename>hibernate.target</filename> target.
1240 <term><command>hybrid-sleep</command></term>
1243 <para>Hibernate and suspend the system. This will trigger
1244 activation of the special
1245 <filename>hybrid-sleep.target</filename> target.</para>
1249 <term><command>switch-root <replaceable>ROOT</replaceable> [<replaceable>INIT</replaceable>]</command></term>
1252 <para>Switches to a different root directory and executes a
1253 new system manager process below it. This is intended for
1254 usage in initial RAM disks ("initrd"), and will transition
1255 from the initrd's system manager process (a.k.a "init"
1256 process) to the main system manager process. This call takes two
1257 arguments: the directory that is to become the new root directory, and
1258 the path to the new system manager binary below it to
1259 execute as PID 1. If the latter is omitted or the empty
1260 string, a systemd binary will automatically be searched for
1261 and used as init. If the system manager path is omitted or
1262 equal to the empty string, the state of the initrd's system
1263 manager process is passed to the main system manager, which
1264 allows later introspection of the state of the services
1265 involved in the initrd boot.</para>
1274 <title>Exit status</title>
1276 <para>On success, 0 is returned, a non-zero failure
1277 code otherwise.</para>
1281 <title>Environment</title>
1283 <variablelist class='environment-variables'>
1285 <term><varname>$SYSTEMD_PAGER</varname></term>
1288 <para>Pager to use when <option>--no-pager</option> is not
1289 given; overrides <varname>$PAGER</varname>. Setting this to
1290 an empty string or the value <literal>cat</literal> is
1291 equivalent to passing
1292 <option>--no-pager</option>.</para>
1299 <title>See Also</title>
1301 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1302 <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1303 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1304 <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1305 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1306 <citerefentry><refentrytitle>systemd.resource-management</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1307 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1308 <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1309 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>