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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>Argument should be a comma-separated list of unit LOAD
115 or SUB or ACTIVE states. When listing units show only those
116 with specified LOAD or SUB or ACTIVE state.</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, cgroup members, 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-cgroup-attr</command>,
437 <command>unset-cgroup-attr</command>,
438 <command>set-cgroup</command> and
439 <command>unset-cgroup</command>, make changes only
440 temporarily, so that they are lost on the next
446 <term><option>-H</option></term>
447 <term><option>--host</option></term>
450 <para>Execute operation remotely. Specify a hostname, or
451 username and hostname separated by <literal>@</literal>, to connect to. This
452 will use SSH to talk to the remote systemd
458 <term><option>-P</option></term>
459 <term><option>--privileged</option></term>
462 <para>Acquire privileges via PolicyKit before executing the
468 <term><option>-n</option></term>
469 <term><option>--lines=</option></term>
472 <para>When used with <command>status</command>, controls the
473 number of journal lines to show, counting from the most
474 recent ones. Takes a positive integer argument. Defaults to
480 <term><option>-o</option></term>
481 <term><option>--output=</option></term>
484 <para>When used with <command>status</command>, controls the
485 formatting of the journal entries that are shown. For the
486 available choices, see
487 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
488 Defaults to <literal>short</literal>.</para>
493 <term><option>--plain</option></term>
496 <para>When used with <command>list-dependencies</command>,
497 the output is printed as a list instead of a tree.</para>
505 <title>Commands</title>
507 <para>The following commands are understood:</para>
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>set-log-level <replaceable>LEVEL</replaceable></command></term>
549 <para>Change current log level of the
550 <command>systemd</command> daemon to
551 <replaceable>LEVEL</replaceable> (accepts the same values
552 as <option>--log-level=</option> described in
553 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>).
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>get-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable>...</command></term>
725 <para>Retrieve the specified control group attributes of the
726 specified unit. Takes a unit name and one or more attribute
727 names such as <literal>cpu.shares</literal>. This will
728 output the current values of the specified attributes,
729 separated by new-lines. For attributes that take a list of
730 items, the output will be newline-separated, too. This
731 operation will always try to retrieve the data in question
732 from the kernel first, and if that is not available, use the
733 configured values instead. Instead of low-level control
734 group attribute names, high-level pretty names may be used,
735 as used for unit execution environment configuration, see
736 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
737 for details. For example, passing
738 <literal>memory.limit_in_bytes</literal> and
739 <literal>MemoryLimit</literal> is equivalent.</para>
744 <term><command>set-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable> <replaceable>VALUE</replaceable>...</command></term>
747 <para>Set the specified control group attribute of the
748 specified unit to the specified value. Takes a unit
749 name and an attribute name such as
750 <literal>cpu.shares</literal>, plus one or more values
751 (multiple values may only be used for attributes that take
752 multiple values). This operation will immediately update the
753 kernel attribute for this unit and persistently store this
754 setting for later reboots (unless <option>--runtime</option>
755 is passed, in which case the setting is not saved
756 persistently and only valid until the next reboot.) Instead
757 of low-level control group attribute names, high-level pretty
758 names may be used, as used for unit execution environment
760 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
761 for details. For example, passing
762 <literal>memory.limit_in_bytes</literal> and
763 <literal>MemoryLimit</literal> is equivalent. This operation
764 will implicitly create a control group for the unit in the
765 controller the attribute belongs to, if needed. For
766 attributes that take multiple values, this operation will
767 append the specified values to the previously set values
768 list (use <command>unset-cgroup-attr</command> to reset the
769 list explicitly). For attributes that take a single value
770 only, the list will be reset implicitly.</para>
775 <term><command>unset-cgroup-attr <replaceable>NAME</replaceable> <replaceable>ATTRIBUTE</replaceable>...</command></term>
777 <listitem><para>Unset the specified control group attributes
778 of the specified unit. Takes a unit name and one or more
779 attribut names such as <literal>cpu.shares</literal>. This
780 operation might or might not have an immediate effect on the
781 current kernel attribute value. This will remove any
782 persistently stored configuration values for this attribute
783 (as set with <command>set-cgroup-attr</command> before),
784 unless <option>--runtime</option> is passed, in which case the
785 configuration is reset only until the next reboot. Again,
786 high-level control group attributes may be used instead of the
787 low-level kernel ones. For attributes which take multiple
788 values, all currently set values are reset.</para>
793 <term><command>set-cgroup <replaceable>NAME</replaceable> <replaceable>CGROUP</replaceable>...</command></term>
794 <term><command>unset-cgroup <replaceable>NAME</replaceable> <replaceable>CGROUP</replaceable>...</command></term>
796 <listitem><para>Add or remove a unit to/from a specific
797 control group hierarchy and/or control group path. Takes a
798 unit name, plus a control group specification in the syntax
799 <replaceable>CONTROLLER</replaceable>:<replaceable>PATH</replaceable>
800 or <replaceable>CONTROLLER</replaceable>. In the latter syntax
801 (where the path is omitted), the default unit control group
802 path is implied. Examples: <literal>cpu</literal> or
803 <literal>cpu:/foo/bar</literal>. If a unit is removed from a
804 control group hierarchy, all its processes will be moved to the
805 root group of the hierarchy and all control group attributes
806 will be reset. These operations are immediately reflected in
807 the kernel hierarchy, and stored persistently to disk (unless
808 <option>--runtime</option> is passed).</para>
813 <term><command>help <replaceable>NAME</replaceable>...|<replaceable>PID</replaceable>...</command></term>
816 <para>Show manual pages for one or more units, if
817 available. If a PID is given, the manual pages for the unit
818 the process belongs to are shown.</para>
823 <term><command>reset-failed [<replaceable>NAME</replaceable>...]</command></term>
826 <para>Reset the <literal>failed</literal> state of the
827 specified units, or if no unit name is passed, reset the state of all
828 units. When a unit fails in some way (i.e. process exiting
829 with non-zero error code, terminating abnormally or timing
830 out), it will automatically enter the
831 <literal>failed</literal> state and its exit code and status
832 is recorded for introspection by the administrator until the
833 service is restarted or reset with this command.</para>
838 <term><command>list-unit-files</command></term>
841 <para>List installed unit files.</para>
846 <term><command>enable <replaceable>NAME</replaceable>...</command></term>
849 <para>Enable one or more unit files or unit file instances,
850 as specified on the command line. This will create a number
851 of symlinks as encoded in the <literal>[Install]</literal>
852 sections of the unit files. After the symlinks have been
853 created, the systemd configuration is reloaded (in a way that
854 is equivalent to <command>daemon-reload</command>) to ensure
855 the changes are taken into account immediately. Note that
856 this does <emphasis>not</emphasis> have the effect of also
857 starting any of the units being enabled. If this
858 is desired, a separate <command>start</command> command must
859 be invoked for the unit. Also note that in case of instance
860 enablement, symlinks named the same as instances are created in
861 the install location, however they all point to the same
862 template unit file.</para>
864 <para>This command will print the actions executed. This
865 output may be suppressed by passing <option>--quiet</option>.
868 <para>Note that this operation creates only the suggested
869 symlinks for the units. While this command is the
870 recommended way to manipulate the unit configuration
871 directory, the administrator is free to make additional
872 changes manually by placing or removing symlinks in the
873 directory. This is particularly useful to create
874 configurations that deviate from the suggested default
875 installation. In this case, the administrator must make sure
876 to invoke <command>daemon-reload</command> manually as
877 necessary to ensure the changes are taken into account.
880 <para>Enabling units should not be confused with starting
881 (activating) units, as done by the <command>start</command>
882 command. Enabling and starting units is orthogonal: units
883 may be enabled without being started and started without
884 being enabled. Enabling simply hooks the unit into various
885 suggested places (for example, so that the unit is
886 automatically started on boot or when a particular kind of
887 hardware is plugged in). Starting actually spawns the daemon
888 process (in case of service units), or binds the socket (in
889 case of socket units), and so on.</para>
891 <para>Depending on whether <option>--system</option>,
892 <option>--user</option> or <option>--global</option> is
893 specified, this enables the unit for the system, for the
894 calling user only or for all future logins of all
895 users. Note that in the last case, no systemd daemon
896 configuration is reloaded.</para>
901 <term><command>disable <replaceable>NAME</replaceable>...</command></term>
904 <para>Disables one or more units. This removes all symlinks
905 to the specified unit files from the unit configuration
906 directory, and hence undoes the changes made by
907 <command>enable</command>. Note however that this removes
908 all symlinks to the unit files (i.e. including manual
909 additions), not just those actually created by
910 <command>enable</command>. This call implicitly reloads the
911 systemd daemon configuration after completing the disabling
912 of the units. Note that this command does not implicitly
913 stop the units that are being disabled. If this is desired,
914 an additional <command>stop</command> command should be
915 executed afterwards.</para>
917 <para>This command will print the actions executed. This
918 output may be suppressed by passing <option>--quiet</option>.
921 <para>This command honors <option>--system</option>,
922 <option>--user</option>, <option>--global</option> in a
923 similar way as <command>enable</command>.</para>
928 <term><command>is-enabled <replaceable>NAME</replaceable>...</command></term>
931 <para>Checks whether any of the specified unit files are
932 enabled (as with <command>enable</command>). Returns an exit
933 code of 0 if at least one is enabled, non-zero
934 otherwise. Prints the current enable status. To suppress
935 this output, use <option>--quiet</option>.</para>
940 <term><command>reenable <replaceable>NAME</replaceable>...</command></term>
943 <para>Reenable one or more unit files, as specified on the
944 command line. This is a combination of
945 <command>disable</command> and <command>enable</command> and
946 is useful to reset the symlinks a unit is enabled with to
947 the defaults configured in the <literal>[Install]</literal>
948 section of the unit file.</para>
953 <term><command>preset <replaceable>NAME</replaceable>...</command></term>
956 <para>Reset one or more unit files, as specified on the
957 command line, to the defaults configured in the preset
958 policy files. This has the same effect as
959 <command>disable</command> or <command>enable</command>,
960 depending how the unit is listed in the preset files. For
961 more information on the preset policy format, see
962 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
963 For more information on the concept of presets, please
965 <ulink url="http://freedesktop.org/wiki/Software/systemd/Preset">Preset</ulink>
971 <term><command>mask <replaceable>NAME</replaceable>...</command></term>
974 <para>Mask one or more unit files, as specified on the
975 command line. This will link these units to
976 <filename>/dev/null</filename>, making it impossible to
977 start them. This is a stronger version of
978 <command>disable</command>, since it prohibits all kinds of
979 activation of the unit, including manual activation. Use
980 this option with care.</para>
985 <term><command>unmask <replaceable>NAME</replaceable>...</command></term>
988 <para>Unmask one or more unit files, as specified on the
989 command line. This will undo the effect of
990 <command>mask</command>.</para>
995 <term><command>link <replaceable>FILENAME</replaceable>...</command></term>
998 <para>Link a unit file that is not in the unit file search
999 paths into the unit file search path. This requires an
1000 absolute path to a unit file. The effect of this can be
1001 undone with <command>disable</command>. The effect of this
1002 command is that a unit file is available for
1003 <command>start</command> and other commands although it
1004 is not installed directly in the unit search path.</para>
1009 <term><command>get-default</command></term>
1012 <para>Get the default target specified
1013 via <filename>default.target</filename> link.</para>
1018 <term><command>set-default <replaceable>NAME</replaceable></command></term>
1021 <para>Set the default target to boot into. Command links
1022 <filename>default.target</filename> to the given unit.</para>
1027 <term><command>load <replaceable>NAME</replaceable>...</command></term>
1030 <para>Load one or more units specified on the command
1031 line. This will simply load their configuration from disk,
1032 but not start them. To start them, you need to use the
1033 <command>start</command> command which will implicitly load
1034 a unit that has not been loaded yet. Note that systemd
1035 garbage collects loaded units that are not active or
1036 referenced by an active unit. This means that units loaded
1037 this way will usually not stay loaded for long. Also note
1038 that this command cannot be used to reload unit
1039 configuration. Use the <command>daemon-reload</command>
1040 command for that. All in all, this command is of little use
1041 except for debugging.</para>
1043 <para>This command should not be confused with the
1044 <command>daemon-reload</command> or
1045 <command>reload</command>.</para>
1049 <term><command>list-jobs</command></term>
1052 <para>List jobs that are in progress.</para>
1056 <term><command>cancel <replaceable>JOB</replaceable>...</command></term>
1059 <para>Cancel one or more jobs specified on the command line
1060 by their numeric job IDs. If no job ID is specified, cancel
1061 all pending jobs.</para>
1065 <term><command>dump</command></term>
1068 <para>Dump server status. This will output a (usually very
1069 long) human readable manager status dump. Its format is
1070 subject to change without notice and should not be parsed by
1071 applications.</para>
1075 <term><command>list-dependencies <replaceable>NAME</replaceable></command></term>
1078 <para>Shows required and wanted units of the specified
1079 unit. If no unit is specified,
1080 <filename>default.target</filename> is implied. Target units
1081 are recursively expanded. When <option>--all</option> is
1082 passed, all other units are recursively expanded as
1087 <term><command>snapshot [<replaceable>NAME</replaceable>]</command></term>
1090 <para>Create a snapshot. If a snapshot name is specified,
1091 the new snapshot will be named after it. If none is
1092 specified, an automatic snapshot name is generated. In either
1093 case, the snapshot name used is printed to STDOUT, unless
1094 <option>--quiet</option> is specified.</para>
1096 <para>A snapshot refers to a saved state of the systemd
1097 manager. It is implemented itself as a unit that is
1098 generated dynamically with this command and has dependencies
1099 on all units active at the time. At a later time, the user
1100 may return to this state by using the
1101 <command>isolate</command> command on the snapshot unit.
1104 <para>Snapshots are only useful for saving and restoring
1105 which units are running or are stopped, they do not
1106 save/restore any other state. Snapshots are dynamic and lost
1111 <term><command>delete <replaceable>NAME</replaceable>...</command></term>
1114 <para>Remove a snapshot previously created with
1115 <command>snapshot</command>.</para>
1119 <term><command>daemon-reload</command></term>
1122 <para>Reload systemd manager configuration. This will reload
1123 all unit files and recreate the entire dependency
1124 tree. While the daemon is reloaded, all sockets systemd
1125 listens on on behalf of user configuration will stay
1126 accessible.</para> <para>This command should not be confused
1127 with the <command>load</command> or
1128 <command>reload</command> commands.</para>
1132 <term><command>daemon-reexec</command></term>
1135 <para>Reexecute the systemd manager. This will serialize the
1136 manager state, reexecute the process and deserialize the
1137 state again. This command is of little use except for
1138 debugging and package upgrades. Sometimes it might be
1139 helpful as a heavy-weight <command>daemon-reload</command>.
1140 While the daemon is reexecuted, all sockets systemd listening
1141 on behalf of user configuration will stay accessible.
1146 <term><command>show-environment</command></term>
1149 <para>Dump the systemd manager environment block. The
1150 environment block will be dumped in straight-forward form
1151 suitable for sourcing into a shell script. This environment
1152 block will be passed to all processes the manager
1157 <term><command>set-environment <replaceable>VARIABLE=VALUE</replaceable>...</command></term>
1160 <para>Set one or more systemd manager environment variables,
1161 as specified on the command line.</para>
1165 <term><command>unset-environment <replaceable>VARIABLE</replaceable>...</command></term>
1168 <para>Unset one or more systemd manager environment
1169 variables. If only a variable name is specified, it will be
1170 removed regardless of its value. If a variable and a value
1171 are specified, the variable is only removed if it has the
1172 specified value.</para>
1176 <term><command>default</command></term>
1179 <para>Enter default mode. This is mostly equivalent to
1180 <command>isolate default.target</command>.</para>
1184 <term><command>rescue</command></term>
1187 <para>Enter rescue mode. This is mostly equivalent to
1188 <command>isolate rescue.target</command>, but also prints a
1189 wall message to all users.</para>
1193 <term><command>emergency</command></term>
1196 <para>Enter emergency mode. This is mostly equivalent to
1197 <command>isolate emergency.target</command>, but also prints
1198 a wall message to all users.</para>
1202 <term><command>halt</command></term>
1205 <para>Shut down and halt the system. This is mostly equivalent to
1206 <command>start halt.target --irreversible</command>, but also
1207 prints a wall message to all users. If combined with
1208 <option>--force</option>, shutdown of all running services is
1209 skipped, however all processes are killed and all file
1210 systems are unmounted or mounted read-only, immediately
1211 followed by the system halt. If <option>--force</option> is
1212 specified twice, the operation is immediately executed
1213 without terminating any processes or unmounting any file
1214 systems. This may result in data loss.</para>
1218 <term><command>poweroff</command></term>
1221 <para>Shut down and power-off the system. This is mostly
1222 equivalent to <command>start poweroff.target --irreversible</command>,
1223 but also prints a wall message to all users. If combined with
1224 <option>--force</option>, shutdown of all running services is
1225 skipped, however all processes are killed and all file
1226 systems are unmounted or mounted read-only, immediately
1227 followed by the powering off. If <option>--force</option> is
1228 specified twice, the operation is immediately executed
1229 without terminating any processes or unmounting any file
1230 systems. This may result in data loss.</para>
1234 <term><command>reboot</command></term>
1237 <para>Shut down and reboot the system. This is mostly
1238 equivalent to <command>start reboot.target --irreversible</command>,
1239 but also prints a wall message to all users. If combined with
1240 <option>--force</option>, shutdown of all running services is
1241 skipped, however all processes are killed and all file
1242 systems are unmounted or mounted read-only, immediately
1243 followed by the reboot. If <option>--force</option> is
1244 specified twice, the operation is immediately executed
1245 without terminating any processes or unmounting any file
1246 systems. This may result in data loss.</para>
1250 <term><command>kexec</command></term>
1253 <para>Shut down and reboot the system via kexec. This is
1254 mostly equivalent to <command>start kexec.target --irreversible</command>,
1255 but also prints a wall message to all users. If combined
1256 with <option>--force</option>, shutdown of all running
1257 services is skipped, however all processes are killed and
1258 all file systems are unmounted or mounted read-only,
1259 immediately followed by the reboot.</para>
1263 <term><command>exit</command></term>
1266 <para>Ask the systemd manager to quit. This is only
1267 supported for user service managers (i.e. in conjunction
1268 with the <option>--user</option> option) and will fail
1274 <term><command>suspend</command></term>
1277 <para>Suspend the system. This will trigger activation of
1278 the special <filename>suspend.target</filename> target.
1283 <term><command>hibernate</command></term>
1286 <para>Hibernate the system. This will trigger activation of
1287 the special <filename>hibernate.target</filename> target.
1292 <term><command>hybrid-sleep</command></term>
1295 <para>Hibernate and suspend the system. This will trigger
1296 activation of the special
1297 <filename>hybrid-sleep.target</filename> target.</para>
1301 <term><command>switch-root <replaceable>ROOT</replaceable> [<replaceable>INIT</replaceable>]</command></term>
1304 <para>Switches to a different root directory and executes a
1305 new system manager process below it. This is intended for
1306 usage in initial RAM disks ("initrd"), and will transition
1307 from the initrd's system manager process (a.k.a "init"
1308 process) to the main system manager process. This call takes two
1309 arguments: the directory that is to become the new root directory, and
1310 the path to the new system manager binary below it to
1311 execute as PID 1. If the latter is omitted or the empty
1312 string, a systemd binary will automatically be searched for
1313 and used as init. If the system manager path is omitted or
1314 equal to the empty string, the state of the initrd's system
1315 manager process is passed to the main system manager, which
1316 allows later introspection of the state of the services
1317 involved in the initrd boot.</para>
1325 <title>Exit status</title>
1327 <para>On success, 0 is returned, a non-zero failure
1328 code otherwise.</para>
1332 <title>Environment</title>
1334 <variablelist class='environment-variables'>
1336 <term><varname>$SYSTEMD_PAGER</varname></term>
1339 <para>Pager to use when <option>--no-pager</option> is not
1340 given; overrides <varname>$PAGER</varname>. Setting this to
1341 an empty string or the value <literal>cat</literal> is
1342 equivalent to passing
1343 <option>--no-pager</option>.</para>
1350 <title>See Also</title>
1352 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1353 <citerefentry><refentrytitle>systemadm</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1354 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1355 <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1356 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1357 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1358 <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1359 <citerefentry><refentrytitle>systemd.preset</refentrytitle><manvolnum>5</manvolnum></citerefentry>