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">
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>, or unit load states such as
98 <option>loaded</option> and <option>masked</option>
99 (types and states can be mixed).</para>
101 <para>If one of the arguments is a unit type, when listing
102 units, limit display to certain unit types. Otherwise units
103 of all types will be shown.</para>
105 <para>If one of the arguments is a unit load state, when
106 listing units, limit display to certain unit
107 types. Otherwise units of in all load states will be
110 <para>As a special case, if one of the arguments is
111 <option>help</option>, a list of allowed values will be
112 printed and the program will exit.</para>
117 <term><option>-p</option></term>
118 <term><option>--property=</option></term>
121 <para>When showing unit/job/manager properties with the
122 <command>show</command> command, limit display to certain
123 properties as specified as argument. If not specified all
124 set properties are shown. The argument should be a
125 comma-seperated list of property names, such as
126 <literal>MainPID</literal>. If specified more than once all
127 properties with the specified names are shown.</para>
132 <term><option>-a</option></term>
133 <term><option>--all</option></term>
136 <para>When listing units, show all loaded units, regardless
137 of their state, including inactive units. When showing
138 unit/job/manager properties, show all properties regardless
139 whether they are set or not.</para>
140 <para>To list all units installed on the system, use the
141 <command>list-unit-files</command> command instead.</para>
146 <term><option>--reverse</option></term>
149 <para>Show reverse dependencies between units with
150 <command>list-dependencies</command>, i.e. units with
151 dependencies of type <varname>Wants=</varname> or
152 <varname>Requires=</varname> on the given unit.
158 <term><option>--after</option></term>
159 <term><option>--before</option></term>
162 <para>Show which units are started after, resp. before
163 with <command>list-dependencies</command>.
169 <term><option>--failed</option></term>
172 <para>When listing units, show only failed units. Do not
173 confuse with <option>--fail</option>.</para>
178 <term><option>--full</option></term>
181 <para>Do not ellipsize unit names, cgroup members, and
182 truncate unit descriptions in the output of
183 <command>list-units</command> and
184 <command>list-jobs</command>.</para>
189 <term><option>--fail</option></term>
192 <para>If the requested operation conflicts with a pending
193 unfinished job, fail the command. If this is not specified
194 the requested operation will replace the pending job, if
195 necessary. Do not confuse with
196 <option>--failed</option>.</para>
201 <term><option>--show-types</option></term>
204 <para>When showing sockets, show the type of the socket.</para>
209 <term><option>--irreversible</option></term>
212 <para>Mark this transaction's jobs as irreversible. This prevents
213 future conflicting transactions from replacing these jobs.
214 The jobs can still be cancelled using the <command>cancel</command>
220 <term><option>--ignore-dependencies</option></term>
223 <para>When enqueuing a new job ignore all its dependencies
224 and execute it immediately. If passed no required units of
225 the unit passed will be pulled in, and no ordering
226 dependencies will be honored. This is mostly a debugging and
227 rescue tool for the administrator and should not be used by
233 <term><option>-i</option></term>
234 <term><option>--ignore-inhibitors</option></term>
237 <para>When system shutdown or a sleep state is requested,
238 ignore inhibitor locks. Applications can establish inhibitor
239 locks to avoid that certain important operations (such as CD
240 burning or suchlike) are interrupted by system shutdown or a
241 sleep state. Any user may take these locks and privileged
242 users may override these locks. If any locks are taken,
243 shutdown and sleep state requests will normally fail
244 (regardless if privileged or not) and a list of active locks
245 is printed. However if <option>--ignore-inhibitors</option>
246 is specified the locks are ignored and not printed, and the
247 operation attempted anyway, possibly requiring additional
253 <term><option>-q</option></term>
254 <term><option>--quiet</option></term>
257 <para>Suppress output to standard output in
258 <command>snapshot</command>,
259 <command>is-active</command>,
260 <command>is-failed</command>,
261 <command>enable</command> and
262 <command>disable</command>.</para>
267 <term><option>--no-block</option></term>
270 <para>Do not synchronously wait for the requested operation
271 to finish. If this is not specified the job will be
272 verified, enqueued and <command>systemctl</command> will
273 wait until it is completed. By passing this argument it is
274 only verified and enqueued.</para>
279 <term><option>--no-legend</option></term>
282 <para>Do not print a legend, i.e. the column headers and
283 the footer with hints.</para>
288 <term><option>--no-pager</option></term>
291 <para>Do not pipe output into a pager.</para>
296 <term><option>--system</option></term>
299 <para>Talk to the systemd system manager. (Default)</para>
304 <term><option>--user</option></term>
307 <para>Talk to the systemd manager of the calling
313 <term><option>--no-wall</option></term>
316 <para>Don't send wall message before halt, power-off,
322 <term><option>--global</option></term>
325 <para>When used with <command>enable</command> and
326 <command>disable</command>, operate on the global user
327 configuration directory, thus enabling or disabling a unit
328 file globally for all future logins of all users.</para>
333 <term><option>--no-reload</option></term>
336 <para>When used with <command>enable</command> and
337 <command>disable</command>, do not implicitly reload daemon
338 configuration after executing the changes.</para>
343 <term><option>--no-ask-password</option></term>
346 <para>When used with <command>start</command> and related
347 commands, disables asking for passwords. Background services
348 may require input of a password or passphrase string, for
349 example to unlock system hard disks or cryptographic
350 certificates. Unless this option is specified and the
351 command is invoked from a terminal
352 <command>systemctl</command> will query the user on the
353 terminal for the necessary secrets. Use this option to
354 switch this behavior off. In this case the password must be
355 supplied by some other means (for example graphical password
356 agents) or the service might fail. This also disables
357 querying the user for authentication for privileged
364 <term><option>--kill-who=</option></term>
367 <para>When used with <command>kill</command>, choose which
368 processes to kill. Must be one of <option>main</option>,
369 <option>control</option> or <option>all</option> to select
370 whether to kill only the main process of the unit, the
371 control process or all processes of the unit. If omitted
372 defaults to <option>all</option>.</para>
378 <term><option>-s</option></term>
379 <term><option>--signal=</option></term>
382 <para>When used with <command>kill</command>, choose which
383 signal to send to selected processes. Must be one of the
384 well known signal specifiers such as SIGTERM, SIGINT or
385 SIGSTOP. If omitted defaults to
386 <option>SIGTERM</option>.</para>
391 <term><option>-f</option></term>
392 <term><option>--force</option></term>
395 <para>When used with <command>enable</command>, overwrite
396 any existing conflicting symlinks.</para>
398 <para>When used with <command>halt</command>,
399 <command>poweroff</command>, <command>reboot</command> or
400 <command>kexec</command> execute the selected operation
401 without shutting down all units. However, all processes will
402 be killed forcibly and all file systems are unmounted or
403 remounted read-only. This is hence a drastic but relatively
404 safe option to request an immediate reboot. If
405 <option>--force</option> is specified twice for these
406 operations, they will be executed immediately without
407 terminating any processes or umounting any file
408 systems. Warning: specifying <option>--force</option> twice
409 with any of these operations might result in data
415 <term><option>--root=</option></term>
419 <command>enable</command>/<command>disable</command>/<command>is-enabled</command>
420 (and related commands), use alternative root path when
421 looking for unit files.</para>
427 <term><option>--runtime</option></term>
430 <para>When used with <command>enable</command>,
431 <command>disable</command>, <command>is-enabled</command>
432 (and related commands), make changes only temporarily, so
433 that they are lost on the next reboot. This will have the
434 effect that changes are not made in subdirectories of
435 <filename>/etc</filename> but in <filename>/run</filename>,
436 with identical immediate effects, however, since the latter
437 is lost on reboot, the changes are lost too.</para>
439 <para>Similar, when used with
440 <command>set-cgroup-attr</command>,
441 <command>unset-cgroup-attr</command>,
442 <command>set-cgroup</command> and
443 <command>unset-cgroup</command>, make changes only
444 temporarily, so that they are lost on the next
450 <term><option>-H</option></term>
451 <term><option>--host</option></term>
454 <para>Execute operation remotely. Specify a hostname, or
455 username and hostname separated by @, to connect to. This
456 will use SSH to talk to the remote systemd
462 <term><option>-P</option></term>
463 <term><option>--privileged</option></term>
466 <para>Acquire privileges via PolicyKit before executing the
472 <term><option>-n</option></term>
473 <term><option>--lines=</option></term>
476 <para>When used with <command>status</command> controls the
477 number of journal lines to show, counting from the most
478 recent ones. Takes a positive integer argument. Defaults to
484 <term><option>-o</option></term>
485 <term><option>--output=</option></term>
488 <para>When used with <command>status</command> controls the
489 formatting of the journal entries that are shown. For the
490 available choices see
491 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
492 Defaults to <literal>short</literal>.</para>
500 <title>Commands</title>
502 <para>The following commands are understood:</para>
506 <term><command>list-units</command></term>
509 <para>List known units (subject to limitations specified
510 with <option>-t</option>).</para>
512 <para>This is the default command.</para>
517 <term><command>list-sockets</command></term>
520 <para>List socket units ordered by the listening address. Produces output
523 LISTEN UNIT ACTIVATES
524 /dev/initctl systemd-initctl.socket systemd-initctl.service
526 [::]:22 sshd.socket sshd.service
527 kobject-uevent 1 systemd-udevd-kernel.socket systemd-udevd.service
531 Note: because the addresses might contains spaces, this output
532 is not suitable for programatic consumption.
535 <para>See also the options <option>--show-types</option>,
536 <option>--all</option>, and <option>--failed</option>.</para>
541 <term><command>start <replaceable>NAME</replaceable>...</command></term>
544 <para>Start (activate) one or more units specified on the
549 <term><command>stop <replaceable>NAME</replaceable>...</command></term>
552 <para>Stop (deactivate) one or more units specified on the
557 <term><command>reload <replaceable>NAME</replaceable>...</command></term>
560 <para>Asks all units listed on the command line to reload
561 their configuration. Note that this will reload the
562 service-specific configuration, not the unit configuration
563 file of systemd. If you want systemd to reload the
564 configuration file of a unit use the
565 <command>daemon-reload</command> command. In other words:
566 for the example case of Apache, this will reload Apache's
567 <filename>httpd.conf</filename> in the web server, not the
568 <filename>apache.service</filename> systemd unit
571 <para>This command should not be confused with the
572 <command>daemon-reload</command> or <command>load</command>
578 <term><command>restart <replaceable>NAME</replaceable>...</command></term>
581 <para>Restart one or more units specified on the command
582 line. If the units are not running yet they will be
587 <term><command>try-restart <replaceable>NAME</replaceable>...</command></term>
590 <para>Restart one or more units specified on the command
591 line if the units are running. Do nothing if units are not
592 running. Note that for compatibility with Red Hat init
593 scripts <command>condrestart</command> is equivalent to this
598 <term><command>reload-or-restart <replaceable>NAME</replaceable>...</command></term>
601 <para>Reload one or more units if they support it. If not,
602 restart them instead. If the units are not running yet they
603 will be started.</para>
607 <term><command>reload-or-try-restart <replaceable>NAME</replaceable>...</command></term>
610 <para>Reload one or more units if they support it. If not,
611 restart them instead. Do nothing if the units are not
612 running. Note that for compatibility with SysV init scripts
613 <command>force-reload</command> is equivalent to this
618 <term><command>isolate <replaceable>NAME</replaceable></command></term>
621 <para>Start the unit specified on the command line and its
622 dependencies and stop all others.</para>
624 <para>This is similar to changing the runlevel in a
625 traditional init system. The <command>isolate</command>
626 command will immediately stop processes that are not enabled
627 in the new unit, possibly including the graphical
628 environment or terminal you are currently using.</para>
630 <para>Note that this is allowed only on units where
631 <option>AllowIsolate=</option> is enabled. See
632 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
637 <term><command>kill <replaceable>NAME</replaceable>...</command></term>
640 <para>Send a signal to one or more processes of the
641 unit. Use <option>--kill-who=</option> to select which
642 process to kill. Use <option>--kill-mode=</option> to select
643 the kill mode and <option>--signal=</option> to select the
644 signal to send.</para>
648 <term><command>is-active <replaceable>NAME</replaceable>...</command></term>
651 <para>Check whether any of the specified units are active
652 (i.e. running). Returns an exit code 0 if at least one is
653 active, non-zero otherwise. Unless <option>--quiet</option>
654 is specified this will also print the current unit state to
659 <term><command>is-failed <replaceable>NAME</replaceable>...</command></term>
662 <para>Check whether any of the specified units are failed.
663 Returns an exit code 0 if at least one is failed, non-zero
664 otherwise. Unless <option>--quiet</option> is specified this
665 will also print the current unit state to
670 <term><command>status [<replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...]</command></term>
673 <para>Show terse runtime status information about one or
674 more units, followed by most recent log data from the
675 journal. If no units are specified, show all units (subject
676 to limitations specified with <option>-t</option>). If a PID
677 is passed show information about the unit the process
680 <para>This function is intended to generate human-readable
681 output. If you are looking for computer-parsable output, use
682 <command>show</command> instead.</para>
686 <term><command>show [<replaceable>NAME</replaceable>...|<replaceable>JOB</replaceable>...]</command></term>
689 <para>Show properties of one or more units, jobs, or the
690 manager itself. If no argument is specified properties of
691 the manager will be shown. If a unit name is specified
692 properties of the unit is shown, and if a job id is
693 specified properties of the job is shown. By default, empty
694 properties are suppressed. Use <option>--all</option> to
695 show those too. To select specific properties to show use
696 <option>--property=</option>. This command is intended to be
697 used whenever computer-parsable output is required. Use
698 <command>status</command> if you are looking for formatted
699 human-readable output.</para>
704 <term><command>get-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable>...</command></term>
707 <para>Retrieve the specified control group attributes of the
708 specified unit. Takes a unit name and one or more attribute
709 names such as <literal>cpu.shares</literal>. This will
710 output the current values of the specified attributes,
711 separated by new-lines. For attributes that take list of
712 items the output will be new-line separated, too. This
713 operation will always try to retrieve the data in question
714 from the kernel first, and if that is not available use the
715 configured values instead. Instead of low-level control
716 group attribute names high-level pretty names may be used,
717 as used for unit execution environment configuration, see
718 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
719 for details. For example, passing
720 <literal>memory.limit_in_bytes</literal> and
721 <literal>MemoryLimit</literal> is equivalent.</para>
726 <term><command>set-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable> <replaceable>VALUE</replaceable>...</command></term>
729 <para>Set the specified control group attribute of the
730 specified unit to the specified value. Takes a unit
731 name and an attribute name such as
732 <literal>cpu.shares</literal>, plus one or more values
733 (multiple values may only be used for attributes that take
734 multiple values). This operation will immediately update the
735 kernel attribute for this unit and persistently store this
736 setting for later reboots (unless <option>--runtime</option>
737 is passed, in which case the setting is not saved
738 persistently and only valid until the next reboot.) Instead
739 of low-level control group attribute names high-level pretty
740 names may be used, as used for unit execution environment
742 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
743 for details. For example, passing
744 <literal>memory.limit_in_bytes</literal> and
745 <literal>MemoryLimit</literal> is equivalent. This operation
746 will implicitly create a control group for the unit in the
747 controller the attribute belongs to, if needed. For
748 attributes that take multiple values, this operation will
749 append the specified values to the previously set values
750 list (use <command>unset-cgroup-attr</command> to reset the
751 list explicitly). For attributes that take a single value
752 only the list will be reset implicitly.</para>
757 <term><command>unset-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable>...</command></term>
759 <listitem><para>Unset the specified control group attributes
760 of the specified unit. Takes a unit name and one or more
761 attribut names such as <literal>cpu.shares</literal>. This
762 operation might or might not have an immediate effect on the
763 current kernel attribute value. This will remove any
764 persistently stored configuration values for this attribute
765 (as set with <command>set-cgroup-attr</command> before),
766 unless <option>--runtime</option> is passed, in which case the
767 configuration is reset only until the next reboot. Again,
768 high-level control group attributes may be used instead of the
769 low-level kernel ones. For attributes which take multiple
770 values, all currently set values are reset.</para>
775 <term><command>set-cgroup <replaceable>NAME</replaceable> <replaceable>CGROUP</replaceable>...</command></term>
776 <term><command>unset-cgroup <replaceable>NAME</replaceable> <replaceable>CGROUP</replaceable>...</command></term>
778 <listitem><para>Add or remove a unit to/from a specific
779 control group hierarchy and/or control group path. Takes a
780 unit name, plus a control group specification in the syntax
781 <replaceable>CONTROLLER</replaceable>:<replaceable>PATH</replaceable>
782 or <replaceable>CONTROLLER</replaceable>. In the latter syntax
783 (where the path is omitted) the default unit control group
784 path is implied. Examples: <literal>cpu</literal> or
785 <literal>cpu:/foo/bar</literal>. If a unit is removed from a
786 control group hierarchy all its processes will be moved to the
787 root group of the hierarchy and all control group attributes
788 will be reset. These operations are immediately reflected in
789 the kernel hierarchy, and stored persistently to disk (unless
790 <option>--runtime</option> is passed).</para>
795 <term><command>help <replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...</command></term>
798 <para>Show manual pages for one or more units, if
799 available. If a PID is passed the manual pages for the unit
800 the process of the PID belongs to is
806 <term><command>reset-failed [<replaceable>NAME</replaceable>...]</command></term>
809 <para>Reset the <literal>failed</literal> state of the
810 specified units, or if no unit name is passed of all
811 units. When a unit fails in some way (i.e. process exiting
812 with non-zero error code, terminating abnormally or timing
813 out) it will automatically enter the
814 <literal>failed</literal> state and its exit code and status
815 is recorded for introspection by the administrator until the
816 service is restarted or reset with this command.</para>
821 <term><command>list-unit-files</command></term>
824 <para>List installed unit files.</para>
829 <term><command>enable <replaceable>NAME</replaceable>...</command></term>
832 <para>Enable one or more unit files or unit file instances,
833 as specified on the command line. This will create a number
834 of symlinks as encoded in the <literal>[Install]</literal>
835 sections of the unit files. After the symlinks have been
836 created the systemd configuration is reloaded (in a way that
837 is equivalent to <command>daemon-reload</command>) to ensure
838 the changes are taken into account immediately. Note that
839 this does not have the effect that any of the units enabled
840 are also started at the same time. If this is desired a
841 separate <command>start</command> command must be invoked
842 for the unit. Also note that in case of instance enablement,
843 symlinks named same as instances are created in install
844 location, however they all point to the same template unit
847 <para>This command will print the actions executed. This
848 output may be suppressed by passing <option>--quiet</option>.
851 <para>Note that this operation creates only the suggested
852 symlinks for the units. While this command is the
853 recommended way to manipulate the unit configuration
854 directory, the administrator is free to make additional
855 changes manually, by placing or removing symlinks in the
856 directory. This is particularly useful to create
857 configurations that deviate from the suggested default
858 installation. In this case the administrator must make sure
859 to invoke <command>daemon-reload</command> manually as
860 necessary, to ensure his changes are taken into account.
863 <para>Enabling units should not be confused with starting
864 (activating) units, as done by the <command>start</command>
865 command. Enabling and starting units is orthogonal: units
866 may be enabled without being started and started without
867 being enabled. Enabling simply hooks the unit into various
868 suggested places (for example, so that the unit is
869 automatically started on boot or when a particular kind of
870 hardware is plugged in). Starting actually spawns the daemon
871 process (in case of service units), or binds the socket (in
872 case of socket units), and so on.</para>
874 <para>Depending on whether <option>--system</option>,
875 <option>--user</option> or <option>--global</option> is
876 specified this enables the unit for the system, for the
877 calling user only or for all future logins of all
878 users. Note that in the last case no systemd daemon
879 configuration is reloaded.</para>
884 <term><command>disable <replaceable>NAME</replaceable>...</command></term>
887 <para>Disables one or more units. This removes all symlinks
888 to the specified unit files from the unit configuration
889 directory, and hence undoes the changes made by
890 <command>enable</command>. Note however that this removes
891 all symlinks to the unit files (i.e. including manual
892 additions), not just those actually created by
893 <command>enable</command>. This call implicitly reloads the
894 systemd daemon configuration after completing the disabling
895 of the units. Note that this command does not implicitly
896 stop the units that are being disabled. If this is desired
897 an additional <command>stop</command> command should be
898 executed afterwards.</para>
900 <para>This command will print the actions executed. This
901 output may be suppressed by passing <option>--quiet</option>.
904 <para>This command honors <option>--system</option>,
905 <option>--user</option>, <option>--global</option> in a
906 similar way as <command>enable</command>.</para>
911 <term><command>is-enabled <replaceable>NAME</replaceable>...</command></term>
914 <para>Checks whether any of the specified unit files are
915 enabled (as with <command>enable</command>). Returns an exit
916 code of 0 if at least one is enabled, non-zero
917 otherwise. Prints the current enable status. To suppress
918 this output use <option>--quiet</option>.</para>
923 <term><command>reenable <replaceable>NAME</replaceable>...</command></term>
926 <para>Reenable one or more unit files, as specified on the
927 command line. This is a combination of
928 <command>disable</command> and <command>enable</command> and
929 is useful to reset the symlinks a unit is enabled with to
930 the defaults configured in the <literal>[Install]</literal>
931 section of the unit file.</para>
936 <term><command>preset <replaceable>NAME</replaceable>...</command></term>
939 <para>Reset one or more unit files, as specified on the
940 command line, to the defaults configured in the preset
941 policy files. This has the same effect as
942 <command>disable</command> or <command>enable</command>,
943 depending how the unit is listed in the preset files. For
944 more information on preset policy format see
945 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
946 For more information on the concept of presets please
948 <ulink url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
954 <term><command>mask <replaceable>NAME</replaceable>...</command></term>
957 <para>Mask one or more unit files, as specified on the
958 command line. This will link these units to
959 <filename>/dev/null</filename>, making it impossible to
960 start them. This is a stronger version of
961 <command>disable</command>, since it prohibits all kinds of
962 activation of the unit, including manual activation. Use
963 this option with care.</para>
968 <term><command>unmask <replaceable>NAME</replaceable>...</command></term>
971 <para>Unmask one or more unit files, as specified on the
972 command line. This will undo the effect of
973 <command>mask</command>.</para>
978 <term><command>link <replaceable>FILENAME</replaceable>...</command></term>
981 <para>Link a unit file that is not in the unit file search
982 paths into the unit file search path. This requires an
983 absolute path to a unit file. The effect of this can be
984 undone with <command>disable</command>. The effect of this
985 command is that a unit file is available for
986 <command>start</command> and other commands although it
987 isn't installed directly in the unit search path.</para>
992 <term><command>load <replaceable>NAME</replaceable>...</command></term>
995 <para>Load one or more units specified on the command
996 line. This will simply load their configuration from disk,
997 but not start them. To start them you need to use the
998 <command>start</command> command which will implicitly load
999 a unit that has not been loaded yet. Note that systemd
1000 garbage collects loaded units that are not active or
1001 referenced by an active unit. This means that units loaded
1002 this way will usually not stay loaded for long. Also note
1003 that this command cannot be used to reload unit
1004 configuration. Use the <command>daemon-reload</command>
1005 command for that. All in all, this command is of little use
1006 except for debugging.</para>
1008 <para>This command should not be confused with the
1009 <command>daemon-reload</command> or
1010 <command>reload</command>.</para>
1014 <term><command>list-jobs</command></term>
1017 <para>List jobs that are in progress.</para>
1021 <term><command>cancel <replaceable>JOB</replaceable>...</command></term>
1024 <para>Cancel one or more jobs specified on the command line
1025 by their numeric job IDs. If no job id is specified, cancel
1026 all pending jobs.</para>
1030 <term><command>dump</command></term>
1033 <para>Dump server status. This will output a (usually very
1034 long) human readable manager status dump. Its format is
1035 subject to change without notice and should not be parsed by
1036 applications.</para>
1040 <term><command>list-dependencies <replaceable>NAME</replaceable></command></term>
1043 <para>Shows required and wanted units of the specified
1044 unit. If no unit is specified
1045 <filename>default.target</filename> is implied. Target units
1046 are recursively expanded. When <option>--all</option> is
1047 passed all other units are recursively expanded as
1052 <term><command>snapshot [<replaceable>NAME</replaceable>]</command></term>
1055 <para>Create a snapshot. If a snapshot name is specified,
1056 the new snapshot will be named after it. If none is
1057 specified an automatic snapshot name is generated. In either
1058 case, the snapshot name used is printed to STDOUT, unless
1059 <option>--quiet</option> is specified.</para>
1061 <para>A snapshot refers to a saved state of the systemd
1062 manager. It is implemented itself as a unit that is
1063 generated dynamically with this command and has dependencies
1064 on all units active at the time. At a later time the user
1065 may return to this state by using the
1066 <command>isolate</command> command on the snapshot unit.
1069 <para>Snapshots are only useful for saving and restoring
1070 which units are running or are stopped, they do not
1071 save/restore any other state. Snapshots are dynamic and lost
1076 <term><command>delete <replaceable>NAME</replaceable>...</command></term>
1079 <para>Remove a snapshot previously created with
1080 <command>snapshot</command>.</para>
1084 <term><command>daemon-reload</command></term>
1087 <para>Reload systemd manager configuration. This will reload
1088 all unit files and recreate the entire dependency
1089 tree. While the daemon is reloaded, all sockets systemd
1090 listens on on behalf of user configuration will stay
1091 accessible.</para> <para>This command should not be confused
1092 with the <command>load</command> or
1093 <command>reload</command> commands.</para>
1097 <term><command>daemon-reexec</command></term>
1100 <para>Reexecute the systemd manager. This will serialize the
1101 manager state, reexecute the process and deserialize the
1102 state again. This command is of little use except for
1103 debugging and package upgrades. Sometimes it might be
1104 helpful as a heavy-weight <command>daemon-reload</command>.
1105 While the daemon is reexecuted all sockets systemd listens
1106 on on behalf of user configuration will stay accessible.
1111 <term><command>show-environment</command></term>
1114 <para>Dump the systemd manager environment block. The
1115 environment block will be dumped in straight-forward form
1116 suitable for sourcing into a shell script. This environment
1117 block will be passed to all processes the manager
1122 <term><command>set-environment <replaceable>VARIABLE=VALUE</replaceable>...</command></term>
1125 <para>Set one or more systemd manager environment variables,
1126 as specified on the command line.</para>
1130 <term><command>unset-environment <replaceable>VARIABLE</replaceable>...</command></term>
1133 <para>Unset one or more systemd manager environment
1134 variables. If only a variable name is specified it will be
1135 removed regardless of its value. If a variable and a value
1136 are specified the variable is only removed if it has the
1137 specified value.</para>
1141 <term><command>default</command></term>
1144 <para>Enter default mode. This is mostly equivalent to
1145 <command>isolate default.target</command>.</para>
1149 <term><command>rescue</command></term>
1152 <para>Enter rescue mode. This is mostly equivalent to
1153 <command>isolate rescue.target</command> but also prints a
1154 wall message to all users.</para>
1158 <term><command>emergency</command></term>
1161 <para>Enter emergency mode. This is mostly equivalent to
1162 <command>isolate emergency.target</command> but also prints
1163 a wall message to all users.</para>
1167 <term><command>halt</command></term>
1170 <para>Shut down and halt the system. This is mostly equivalent to
1171 <command>start halt.target --irreversible</command> but also
1172 prints a wall message to all users. If combined with
1173 <option>--force</option> shutdown of all running services is
1174 skipped, however all processes are killed and all file
1175 systems are unmounted or mounted read-only, immediately
1176 followed by the system halt. If <option>--force</option> is
1177 specified twice the operation is immediately executed
1178 without terminating any processes or unmounting any file
1179 systems. This may result in data loss.</para>
1183 <term><command>poweroff</command></term>
1186 <para>Shut down and power-off the system. This is mostly
1187 equivalent to <command>start poweroff.target --irreversible</command>
1188 but also prints a wall message to all users. If combined with
1189 <option>--force</option> shutdown of all running services is
1190 skipped, however all processes are killed and all file
1191 systems are unmounted or mounted read-only, immediately
1192 followed by the powering off. If <option>--force</option> is
1193 specified twice the operation is immediately executed
1194 without terminating any processes or unmounting any file
1195 systems. This may result in data loss.</para>
1199 <term><command>reboot</command></term>
1202 <para>Shut down and reboot the system. This is mostly
1203 equivalent to <command>start reboot.target --irreversible</command>
1204 but also prints a wall message to all users. If combined with
1205 <option>--force</option> shutdown of all running services is
1206 skipped, however all processes are killed and all file
1207 systems are unmounted or mounted read-only, immediately
1208 followed by the reboot. If <option>--force</option> is
1209 specified twice the operation is immediately executed
1210 without terminating any processes or unmounting any file
1211 systems. This may result in data loss.</para>
1215 <term><command>kexec</command></term>
1218 <para>Shut down and reboot the system via kexec. This is
1219 mostly equivalent to <command>start kexec.target --irreversible</command>
1220 but also prints a wall message to all users. If combined
1221 with <option>--force</option> shutdown of all running
1222 services is skipped, however all processes are killed and
1223 all file systems are unmounted or mounted read-only,
1224 immediately followed by the reboot.</para>
1228 <term><command>exit</command></term>
1231 <para>Ask the systemd manager to quit. This is only
1232 supported for user service managers (i.e. in conjunction
1233 with the <option>--user</option> option) and will fail
1239 <term><command>suspend</command></term>
1242 <para>Suspend the system. This will trigger activation of
1243 the special <filename>suspend.target</filename> target.
1248 <term><command>hibernate</command></term>
1251 <para>Hibernate the system. This will trigger activation of
1252 the special <filename>hibernate.target</filename> target.
1257 <term><command>hybrid-sleep</command></term>
1260 <para>Hibernate and suspend the system. This will trigger
1261 activation of the special
1262 <filename>hybrid-sleep.target</filename> target.</para>
1266 <term><command>switch-root <replaceable>ROOT</replaceable> [<replaceable>INIT</replaceable>]</command></term>
1269 <para>Switches to a different root directory and executes a
1270 new system manager process below it. This is intended for
1271 usage in initial RAM disks ("initrd"), and will transition
1272 from the initrd's system manager process (a.k.a "init"
1273 process) to the main system manager process. Takes two
1274 arguments: the directory to make the new root directory, and
1275 the path to the new system manager binary below it to
1276 execute as PID 1. If the latter is omitted or the empty
1277 string, a systemd binary will automatically be searched for
1278 and used as init. If the system manager path is omitted or
1279 equal to the empty string the state of the initrd's system
1280 manager process is passed to the main system manager, which
1281 allows later introspection of the state of the services
1282 involved in the initrd boot.</para>
1290 <title>Exit status</title>
1292 <para>On success 0 is returned, a non-zero failure
1293 code otherwise.</para>
1297 <title>Environment</title>
1299 <variablelist class='environment-variables'>
1301 <term><varname>$SYSTEMD_PAGER</varname></term>
1304 <para>Pager to use when <option>--no-pager</option> is not
1305 given; overrides <varname>$PAGER</varname>. Setting this to
1306 an empty string or the value <literal>cat</literal> is
1307 equivalent to passing
1308 <option>--no-pager</option>.</para>
1315 <title>See Also</title>
1317 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1318 <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1319 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1320 <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1321 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1322 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1323 <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1324 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>