1 <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
6 SPDX-License-Identifier: LGPL-2.1+
8 Copyright 2010 Lennart Poettering
11 <refentry id="elogind"
12 xmlns:xi="http://www.w3.org/2001/XInclude">
15 <title>elogind</title>
16 <productname>elogind</productname>
20 <contrib>Developer</contrib>
21 <firstname>Lennart</firstname>
22 <surname>Poettering</surname>
23 <email>lennart@poettering.net</email>
29 <refentrytitle>elogind</refentrytitle>
30 <!-- 0 /// elogind is in section 8
31 <manvolnum>1</manvolnum>
33 <manvolnum>8</manvolnum>
38 <!-- 0 /// Well, elogind isn't that much...
39 <refname>systemd</refname>
40 <refname>init</refname>
41 <refpurpose>systemd system and service manager</refpurpose>
43 <refname>elogind</refname>
44 <refpurpose>Login manager</refpurpose>
49 <!-- 0 /// elogind has a different synopsis of course...
51 <command>/usr/lib/systemd/systemd</command>
52 <arg choice="opt" rep="repeat">OPTIONS</arg>
55 <command>init</command>
56 <arg choice="opt" rep="repeat">OPTIONS</arg>
57 <arg choice="req">COMMAND</arg>
61 <command>elogind</command>
62 <arg choice="opt" rep="repeat">OPTIONS</arg>
63 <arg choice="req">COMMAND</arg>
69 <title>Description</title>
71 <!-- 0 /// elogind does not need that much explanation.
72 <para>systemd is a system and service manager for Linux operating
73 systems. When run as first process on boot (as PID 1), it acts as
74 init system that brings up and maintains userspace
77 <para>For compatibility with SysV, if systemd is called as
78 <command>init</command> and a PID that is not 1, it will execute
79 <command>telinit</command> and pass all command line arguments
80 unmodified. That means <command>init</command> and
81 <command>telinit</command> are mostly equivalent when invoked from
82 normal login sessions. See
83 <citerefentry><refentrytitle>telinit</refentrytitle><manvolnum>8</manvolnum></citerefentry>
84 for more information.</para>
86 <para>When run as a system instance, systemd interprets the
87 configuration file <filename>system.conf</filename> and the files
88 in <filename>system.conf.d</filename> directories; when run as a
89 user instance, systemd interprets the configuration file
90 <filename>user.conf</filename> and the files in
91 <filename>user.conf.d</filename> directories. See
92 <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
93 for more information.</para>
95 <para><command>elogind</command> is a system service that
96 manages user logins. It is responsible for:</para>
99 <listitem><para>Keeping track of users and sessions, their
100 processes and their idle state</para></listitem>
102 <listitem><para>Providing PolicyKit-based access for users to
103 operations such as system shutdown or sleep</para></listitem>
105 <listitem><para>Implementing a shutdown/sleep inhibition logic
106 for applications</para></listitem>
108 <listitem><para>Handling of power/sleep hardware
109 keys</para></listitem>
111 <listitem><para>Multi-seat management</para></listitem>
113 <listitem><para>Session switch management</para></listitem>
115 <listitem><para>Device access management for
116 users</para></listitem>
120 <para>User sessions are registered in elogind via the
121 <citerefentry><refentrytitle>pam_elogind</refentrytitle><manvolnum>8</manvolnum></citerefentry>
125 <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
126 for information about the configuration of this service.</para>
129 url="http://www.freedesktop.org/wiki/Software/systemd/multiseat">Multi-Seat
130 on Linux</ulink> for an introduction into basic concepts of logind
131 such as users, sessions and seats.</para>
134 url="http://www.freedesktop.org/wiki/Software/systemd/logind">
135 logind D-Bus API Documentation</ulink> for information about the
136 APIs <filename>logind</filename> provides.</para>
138 <para>For more information on the inhibition logic see the <ulink
139 url="http://www.freedesktop.org/wiki/Software/systemd/inhibit">Inhibitor
140 Lock Developer Documentation</ulink>.</para>
145 <title>Options</title>
147 <para>The following options are understood:</para>
150 <!-- 0 /// This list is much shorter with elogind of course.
152 <term><option>--test</option></term>
154 <listitem><para>Determine startup sequence, dump it and exit.
155 This is an option useful for debugging only.</para></listitem>
158 <term><option>--dump-configuration-items</option></term>
160 <listitem><para>Dump understood unit configuration items. This
161 outputs a terse but complete list of configuration items
162 understood in unit definition files.</para></listitem>
165 <term><option>--dump-bus-properties</option></term>
167 <listitem><para>Dump exposed bus properties. This outputs
168 a terse but complete list of properties exposed to dbus.
172 <term><option>--unit=</option></term>
174 <listitem><para>Set default unit to activate on startup. If
175 not specified, defaults to
176 <filename>default.target</filename>.</para></listitem>
179 <term><option>--system</option></term>
180 <term><option>--user</option></term>
182 <listitem><para>For <option>--system</option>, tell systemd to
183 run a system instance, even if the process ID is not 1, i.e.
184 systemd is not run as init process. <option>--user</option>
185 does the opposite, running a user instance even if the process
186 ID is 1. Normally, it should not be necessary to pass these
187 options, as systemd automatically detects the mode it is
188 started in. These options are hence of little use except for
189 debugging. Note that it is not supported booting and
190 maintaining a full system with systemd running in
191 <option>--system</option> mode, but PID not 1. In practice,
192 passing <option>--system</option> explicitly is only useful in
193 conjunction with <option>--test</option>.</para></listitem>
196 <term><option>--dump-core</option></term>
198 <listitem><para>Enable core dumping on crash. This switch has
199 no effect when running as user instance. This setting may also
200 be enabled during boot on the kernel command line via the
201 <varname>systemd.dump_core=</varname> option, see
202 below.</para></listitem>
206 <term><option>--crash-vt=</option><replaceable>VT</replaceable></term>
208 <listitem><para>Switch to a specific virtual console (VT) on
209 crash. Takes a positive integer in the range 1–63, or a
210 boolean argument. If an integer is passed, selects which VT to
211 switch to. If <constant>yes</constant>, the VT kernel messages
212 are written to is selected. If <constant>no</constant>, no VT
213 switch is attempted. This switch has no effect when running as
214 user instance. This setting may also be enabled during boot,
215 on the kernel command line via the
216 <varname>systemd.crash_vt=</varname> option, see
218 <!-- FIXME: there is no crash_vt command line option? -->
219 <!-- 0 /// elogind check_tree.pl can not mangle closed comments.
220 below.</para></listitem>
224 <term><option>--crash-shell</option></term>
226 <listitem><para>Run a shell on crash. This switch has no
227 effect when running as user instance. This setting may also be
228 enabled during boot, on the kernel command line via the
229 <varname>systemd.crash_shell=</varname> option, see
230 below.</para></listitem>
234 <term><option>--crash-reboot</option></term>
236 <listitem><para>Automatically reboot the system on crash. This
237 switch has no effect when running as user instance. This
238 setting may also be enabled during boot, on the kernel command
239 line via the <varname>systemd.crash_reboot=</varname> option,
240 see below.</para></listitem>
244 <term><option>--confirm-spawn</option></term>
246 <listitem><para>Ask for confirmation when spawning processes.
247 This switch has no effect when run as user
248 instance.</para></listitem>
251 <term><option>--show-status=</option></term>
253 <listitem><para>Takes a boolean argument or the special value <constant>auto</constant>. If on, terse unit
254 status information is shown on the console during boot-up and shutdown. If off, no such status information is
255 shown. If set to <constant>auto</constant> behavior is similar to off, except that it is automatically switched
256 to on, as soon as the first unit failure or significant boot delay is encountered. This switch has no effect
257 when invoked as user instance. If specified, overrides both the kernel command line setting
258 <varname>systemd.show_status=</varname> (see below) and the configuration file option
259 <option>ShowStatus=</option>, see
260 <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
263 <term><option>--log-target=</option></term>
265 <listitem><para>Set log target. Argument must be one of
266 <option>console</option>,
267 <option>journal</option>,
268 <option>kmsg</option>,
269 <option>journal-or-kmsg</option>,
270 <option>null</option>.</para></listitem>
273 <term><option>--log-level=</option></term>
275 <listitem><para>Set log level. As
276 argument this accepts a numerical log
277 level or the well-known <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
278 symbolic names (lowercase):
279 <option>emerg</option>,
280 <option>alert</option>,
281 <option>crit</option>,
282 <option>err</option>,
283 <option>warning</option>,
284 <option>notice</option>,
285 <option>info</option>,
286 <option>debug</option>.</para></listitem>
289 <term><option>--log-color=</option></term>
291 <listitem><para>Highlight important log messages. Argument is
292 a boolean value. If the argument is omitted, it defaults to
293 <option>true</option>.</para></listitem>
296 <term><option>--log-location=</option></term>
298 <listitem><para>Include code location in log messages. This is
299 mostly relevant for debugging purposes. Argument is a boolean
300 value. If the argument is omitted it defaults to
301 <option>true</option>.</para></listitem>
304 <term><option>--default-standard-output=</option></term>
305 <term><option>--default-standard-error=</option></term>
307 <listitem><para>Sets the default output or error output for
308 all services and sockets, respectively. That is, controls the
309 default for <option>StandardOutput=</option> and
310 <option>StandardError=</option> (see
311 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
312 for details). Takes one of
313 <option>inherit</option>,
314 <option>null</option>,
315 <option>tty</option>,
316 <option>journal</option>,
317 <option>journal+console</option>,
318 <option>syslog</option>,
319 <option>syslog+console</option>,
320 <option>kmsg</option>,
321 <option>kmsg+console</option>. If the
323 <option>--default-standard-output=</option> defaults to
324 <option>journal</option> and
325 <option>--default-standard-error=</option> to
326 <option>inherit</option>.</para></listitem>
330 <term><option>--machine-id=</option></term>
332 <listitem><para>Override the machine-id set on the hard drive,
333 useful for network booting or for containers. May not be set
334 to all zeros.</para></listitem>
338 <term><option>--service-watchdogs=</option></term>
340 <listitem><para>Globally enable/disable all service watchdog timeouts and emergency
341 actions. This setting may also be specified during boot, on the kernel
342 command line via the <varname>systemd.service_watchdogs=</varname>
343 option, see below. Defaults to enabled.</para></listitem>
346 <xi:include href="standard-options.xml" xpointer="help" />
347 <xi:include href="standard-options.xml" xpointer="version" />
350 <term><option>-D</option></term>
351 <term><option>--daemon</option></term>
353 <listitem><para>Daemonize elogind by double-forking
354 into background.</para></listitem>
358 <term><option>-h</option></term>
359 <term><option>--help</option></term>
361 <listitem><para>Show the helpt text and exit.</para></listitem>
367 <!-- 0 /// The whole concpets section is unneeded in elogind
369 <title>Concepts</title>
371 <para>systemd provides a dependency system between various
372 entities called "units" of 11 different types. Units encapsulate
373 various objects that are relevant for system boot-up and
374 maintenance. The majority of units are configured in unit
375 configuration files, whose syntax and basic set of options is
377 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
378 however some are created automatically from other configuration,
379 dynamically from system state or programmatically at runtime.
380 Units may be "active" (meaning started, bound, plugged in, …,
381 depending on the unit type, see below), or "inactive" (meaning
382 stopped, unbound, unplugged, …), as well as in the process of
383 being activated or deactivated, i.e. between the two states (these
384 states are called "activating", "deactivating"). A special
385 "failed" state is available as well, which is very similar to
386 "inactive" and is entered when the service failed in some way
387 (process returned error code on exit, or crashed, an operation
388 timed out, or after too many restarts). If this state is entered,
389 the cause will be logged, for later reference. Note that the
390 various unit types may have a number of additional substates,
391 which are mapped to the five generalized unit states described
394 <para>The following unit types are available:</para>
397 <listitem><para>Service units, which start and control daemons
398 and the processes they consist of. For details, see
399 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
401 <listitem><para>Socket units, which encapsulate local IPC or
402 network sockets in the system, useful for socket-based
403 activation. For details about socket units, see
404 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
405 for details on socket-based activation and other forms of
407 <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem>
409 <listitem><para>Target units are useful to group units, or
410 provide well-known synchronization points during boot-up, see
411 <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
413 <listitem><para>Device units expose kernel devices in systemd
414 and may be used to implement device-based activation. For
416 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
418 <listitem><para>Mount units control mount points in the file
419 system, for details see
420 <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
422 <listitem><para>Automount units provide automount capabilities,
423 for on-demand mounting of file systems as well as parallelized
425 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
427 <listitem><para>Timer units are useful for triggering activation
428 of other units based on timers. You may find details in
429 <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
431 <listitem><para>Swap units are very similar to mount units and
432 encapsulate memory swap partitions or files of the operating
433 system. They are described in
434 <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
436 <listitem><para>Path units may be used to activate other
437 services when file system objects change or are modified. See
438 <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
440 <listitem><para>Slice units may be used to group units which
441 manage system processes (such as service and scope units) in a
442 hierarchical tree for resource management purposes. See
443 <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
445 <listitem><para>Scope units are similar to service units, but
446 manage foreign processes instead of starting them as well. See
447 <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
451 <para>Units are named as their configuration files. Some units
452 have special semantics. A detailed list is available in
453 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
455 <para>systemd knows various kinds of dependencies, including
456 positive and negative requirement dependencies (i.e.
457 <varname>Requires=</varname> and <varname>Conflicts=</varname>) as
458 well as ordering dependencies (<varname>After=</varname> and
459 <varname>Before=</varname>). NB: ordering and requirement
460 dependencies are orthogonal. If only a requirement dependency
461 exists between two units (e.g. <filename>foo.service</filename>
462 requires <filename>bar.service</filename>), but no ordering
463 dependency (e.g. <filename>foo.service</filename> after
464 <filename>bar.service</filename>) and both are requested to start,
465 they will be started in parallel. It is a common pattern that both
466 requirement and ordering dependencies are placed between two
467 units. Also note that the majority of dependencies are implicitly
468 created and maintained by systemd. In most cases, it should be
469 unnecessary to declare additional dependencies manually, however
470 it is possible to do this.</para>
472 <para>Application programs and units (via dependencies) may
473 request state changes of units. In systemd, these requests are
474 encapsulated as 'jobs' and maintained in a job queue. Jobs may
475 succeed or can fail, their execution is ordered based on the
476 ordering dependencies of the units they have been scheduled
479 <para>On boot systemd activates the target unit
480 <filename>default.target</filename> whose job is to activate
481 on-boot services and other on-boot units by pulling them in via
482 dependencies. Usually, the unit name is just an alias (symlink) for
483 either <filename>graphical.target</filename> (for fully-featured
484 boots into the UI) or <filename>multi-user.target</filename> (for
485 limited console-only boots for use in embedded or server
486 environments, or similar; a subset of graphical.target). However,
487 it is at the discretion of the administrator to configure it as an
488 alias to any other target unit. See
489 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
490 for details about these target units.</para>
492 <para>Processes systemd spawns are placed in individual Linux
493 control groups named after the unit which they belong to in the
494 private systemd hierarchy. (see <ulink
495 url="https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt">cgroups.txt</ulink>
496 for more information about control groups, or short "cgroups").
497 systemd uses this to effectively keep track of processes. Control
498 group information is maintained in the kernel, and is accessible
499 via the file system hierarchy (beneath
500 <filename>/sys/fs/cgroup/systemd/</filename>), or in tools such as
501 <citerefentry project='man-pages'><refentrytitle>systemd-cgls</refentrytitle><manvolnum>1</manvolnum></citerefentry>
503 <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>
504 (<command>ps xawf -eo pid,user,cgroup,args</command> is
505 particularly useful to list all processes and the systemd units
506 they belong to.).</para>
508 <para>systemd is compatible with the SysV init system to a large
509 degree: SysV init scripts are supported and simply read as an
510 alternative (though limited) configuration file format. The SysV
511 <filename>/dev/initctl</filename> interface is provided, and
512 compatibility implementations of the various SysV client tools are
513 available. In addition to that, various established Unix
514 functionality such as <filename>/etc/fstab</filename> or the
515 <filename>utmp</filename> database are supported.</para>
517 <para>systemd has a minimal transaction system: if a unit is
518 requested to start up or shut down it will add it and all its
519 dependencies to a temporary transaction. Then, it will verify if
520 the transaction is consistent (i.e. whether the ordering of all
521 units is cycle-free). If it is not, systemd will try to fix it up,
522 and removes non-essential jobs from the transaction that might
523 remove the loop. Also, systemd tries to suppress non-essential
524 jobs in the transaction that would stop a running service. Finally
525 it is checked whether the jobs of the transaction contradict jobs
526 that have already been queued, and optionally the transaction is
527 aborted then. If all worked out and the transaction is consistent
528 and minimized in its impact it is merged with all already
529 outstanding jobs and added to the run queue. Effectively this
530 means that before executing a requested operation, systemd will
531 verify that it makes sense, fixing it if possible, and only
532 failing if it really cannot work.</para>
534 <para>systemd contains native implementations of various tasks
535 that need to be executed as part of the boot process. For example,
536 it sets the hostname or configures the loopback network device. It
537 also sets up and mounts various API file systems, such as
538 <filename>/sys</filename> or <filename>/proc</filename>.</para>
540 <para>For more information about the concepts and
541 ideas behind systemd, please refer to the
542 <ulink url="http://0pointer.de/blog/projects/systemd.html">Original Design Document</ulink>.</para>
544 <para>Note that some but not all interfaces provided
545 by systemd are covered by the
546 <ulink url="https://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
547 Stability Promise</ulink>.</para>
549 <para>Units may be generated dynamically at boot and system
550 manager reload time, for example based on other configuration
551 files or parameters passed on the kernel command line. For details, see
552 <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
554 <para>Systems which invoke systemd in a container or initrd
555 environment should implement the
556 <ulink url="https://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container Interface</ulink> or
557 <ulink url="https://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd Interface</ulink>
558 specifications, respectively.</para>
562 <!-- 0 /// The whole directories section is unneeded in elogind
564 <title>Directories</title>
568 <term>System unit directories</term>
570 <listitem><para>The systemd system manager reads unit
571 configuration from various directories. Packages that want to
572 install unit files shall place them in the directory returned
573 by <command>pkg-config systemd
574 --variable=systemdsystemunitdir</command>. Other directories
575 checked are <filename>/usr/local/lib/systemd/system</filename>
576 and <filename>/usr/lib/systemd/system</filename>. User
577 configuration always takes precedence. <command>pkg-config
578 systemd --variable=systemdsystemconfdir</command> returns the
579 path of the system configuration directory. Packages should
580 alter the content of these directories only with the
581 <command>enable</command> and <command>disable</command>
583 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
584 tool. Full list of directories is provided in
585 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
592 <term>User unit directories</term>
594 <listitem><para>Similar rules apply for the user unit
595 directories. However, here the
596 <ulink url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
597 Base Directory specification</ulink> is followed to find
598 units. Applications should place their unit files in the
599 directory returned by <command>pkg-config systemd
600 --variable=systemduserunitdir</command>. Global configuration
601 is done in the directory reported by <command>pkg-config
602 systemd --variable=systemduserconfdir</command>. The
603 <command>enable</command> and <command>disable</command>
605 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
606 tool can handle both global (i.e. for all users) and private
607 (for one user) enabling/disabling of units. Full list of
608 directories is provided in
609 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
616 <term>SysV init scripts directory</term>
618 <listitem><para>The location of the SysV init script directory
619 varies between distributions. If systemd cannot find a native
620 unit file for a requested service, it will look for a SysV
621 init script of the same name (with the
622 <filename>.service</filename> suffix
623 removed).</para></listitem>
629 <term>SysV runlevel link farm directory</term>
631 <listitem><para>The location of the SysV runlevel link farm
632 directory varies between distributions. systemd will take the
633 link farm into account when figuring out whether a service
634 shall be enabled. Note that a service unit with a native unit
635 configuration file cannot be started by activating it in the
636 SysV runlevel link farm.</para></listitem>
642 <!-- 0 /// The whole Signals section is unneeded in elogind
644 <title>Signals</title>
648 <term><constant>SIGTERM</constant></term>
650 <listitem><para>Upon receiving this signal the systemd system
651 manager serializes its state, reexecutes itself and
652 deserializes the saved state again. This is mostly equivalent
653 to <command>systemctl daemon-reexec</command>.</para>
655 <para>systemd user managers will start the
656 <filename>exit.target</filename> unit when this signal is
657 received. This is mostly equivalent to <command>systemctl
658 --user start exit.target
659 --job-mode=replace-irreversible</command>.</para></listitem>
663 <term><constant>SIGINT</constant></term>
665 <listitem><para>Upon receiving this signal the systemd system
666 manager will start the
667 <filename>ctrl-alt-del.target</filename> unit. This is mostly
668 equivalent to <command>systemctl start ctrl-alt-del.target
669 --job-mode=replace-irreversible</command>. If this signal is
670 received more than 7 times per 2s, an immediate reboot is
671 triggered. Note that pressing Ctrl-Alt-Del on the console
672 will trigger this signal. Hence, if a reboot is hanging,
673 pressing Ctrl-Alt-Del more than 7 times in 2s is a relatively
674 safe way to trigger an immediate reboot.</para>
676 <para>systemd user managers treat this signal the same way as
677 <constant>SIGTERM</constant>.</para></listitem>
681 <term><constant>SIGWINCH</constant></term>
683 <listitem><para>When this signal is received the systemd
684 system manager will start the
685 <filename>kbrequest.target</filename> unit. This is mostly
686 equivalent to <command>systemctl start
687 kbrequest.target</command>.</para>
689 <para>This signal is ignored by systemd user
690 managers.</para></listitem>
694 <term><constant>SIGPWR</constant></term>
696 <listitem><para>When this signal is received the systemd
697 manager will start the <filename>sigpwr.target</filename>
698 unit. This is mostly equivalent to <command>systemctl start
699 sigpwr.target</command>.</para></listitem>
703 <term><constant>SIGUSR1</constant></term>
705 <listitem><para>When this signal is received the systemd
706 manager will try to reconnect to the D-Bus
707 bus.</para></listitem>
711 <term><constant>SIGUSR2</constant></term>
713 <listitem><para>When this signal is received the systemd
714 manager will log its complete state in human-readable form.
715 The data logged is the same as printed by
716 <command>systemd-analyze dump</command>.</para></listitem>
720 <term><constant>SIGHUP</constant></term>
722 <listitem><para>Reloads the complete daemon configuration.
723 This is mostly equivalent to <command>systemctl
724 daemon-reload</command>.</para></listitem>
728 <term><constant>SIGRTMIN+0</constant></term>
730 <listitem><para>Enters default mode, starts the
731 <filename>default.target</filename> unit. This is mostly
732 equivalent to <command>systemctl isolate
733 default.target</command>.</para></listitem>
737 <term><constant>SIGRTMIN+1</constant></term>
739 <listitem><para>Enters rescue mode, starts the
740 <filename>rescue.target</filename> unit. This is mostly
741 equivalent to <command>systemctl isolate
742 rescue.target</command>.</para></listitem>
746 <term><constant>SIGRTMIN+2</constant></term>
748 <listitem><para>Enters emergency mode, starts the
749 <filename>emergency.service</filename> unit. This is mostly
750 equivalent to <command>systemctl isolate
751 emergency.service</command>.</para></listitem>
755 <term><constant>SIGRTMIN+3</constant></term>
757 <listitem><para>Halts the machine, starts the
758 <filename>halt.target</filename> unit. This is mostly
759 equivalent to <command>systemctl start halt.target
760 --job-mode=replace-irreversible</command>.</para>
765 <term><constant>SIGRTMIN+4</constant></term>
767 <listitem><para>Powers off the machine, starts the
768 <filename>poweroff.target</filename> unit. This is mostly
769 equivalent to <command>systemctl start poweroff.target
770 --job-mode=replace-irreversible</command>.</para>
775 <term><constant>SIGRTMIN+5</constant></term>
777 <listitem><para>Reboots the machine, starts the
778 <filename>reboot.target</filename> unit. This is mostly
779 equivalent to <command>systemctl start reboot.target
780 --job-mode=replace-irreversible</command>.</para>
785 <term><constant>SIGRTMIN+6</constant></term>
787 <listitem><para>Reboots the machine via kexec, starts the
788 <filename>kexec.target</filename> unit. This is mostly
789 equivalent to <command>systemctl start kexec.target
790 --job-mode=replace-irreversible</command>.</para>
795 <term><constant>SIGRTMIN+13</constant></term>
797 <listitem><para>Immediately halts the machine.</para></listitem>
801 <term><constant>SIGRTMIN+14</constant></term>
803 <listitem><para>Immediately powers off the machine.</para></listitem>
807 <term><constant>SIGRTMIN+15</constant></term>
809 <listitem><para>Immediately reboots the machine.</para></listitem>
813 <term><constant>SIGRTMIN+16</constant></term>
815 <listitem><para>Immediately reboots the machine with kexec.</para></listitem>
819 <term><constant>SIGRTMIN+20</constant></term>
821 <listitem><para>Enables display of status messages on the
822 console, as controlled via
823 <varname>systemd.show_status=1</varname> on the kernel command
824 line.</para></listitem>
828 <term><constant>SIGRTMIN+21</constant></term>
830 <listitem><para>Disables display of
831 status messages on the console, as
833 <varname>systemd.show_status=0</varname>
834 on the kernel command
835 line.</para></listitem>
839 <term><constant>SIGRTMIN+22</constant></term>
841 <listitem><para>Sets the service manager's log level to <literal>debug</literal>, in a fashion equivalent to
842 <varname>systemd.log_level=debug</varname> on the kernel command line.</para></listitem>
846 <term><constant>SIGRTMIN+23</constant></term>
848 <listitem><para>Restores the log level to its configured value. The configured value is derived from – in order
849 of priority – the value specified with <varname>systemd.log-level=</varname> on the kernel command line, or the
850 value specified with <option>LogLevel=</option> in the configuration file, or the built-in default of
851 <literal>info</literal>.</para></listitem>
855 <term><constant>SIGRTMIN+24</constant></term>
857 <listitem><para>Immediately exits the manager (only available
858 for --user instances).</para></listitem>
862 <term><constant>SIGRTMIN+26</constant></term>
864 <listitem><para>Restores the log target to its configured value. The configured value is derived from – in
865 order of priority – the value specified with <varname>systemd.log-target=</varname> on the kernel command line,
866 or the value specified with <option>LogTarget=</option> in the configuration file, or the built-in
867 default.</para></listitem>
871 <term><constant>SIGRTMIN+27</constant></term>
872 <term><constant>SIGRTMIN+28</constant></term>
874 <listitem><para>Sets the log target to <literal>console</literal> on <constant>SIGRTMIN+27</constant> (or
875 <literal>kmsg</literal> on <constant>SIGRTMIN+28</constant>), in a fashion equivalent to
876 <varname>systemd.log_target=console</varname> (or <varname>systemd.log_target=kmsg</varname> on
877 <constant>SIGRTMIN+28</constant>) on the kernel command line.</para></listitem>
883 <!-- 0 /// The whole environment section is unneeded in elogind
885 <title>Environment</title>
887 <variablelist class='environment-variables'>
889 <term><varname>$SYSTEMD_LOG_LEVEL</varname></term>
890 <listitem><para>systemd reads the log level from this
891 environment variable. This can be overridden with
892 <option>--log-level=</option>.</para></listitem>
896 <term><varname>$SYSTEMD_LOG_TARGET</varname></term>
897 <listitem><para>systemd reads the log target from this
898 environment variable. This can be overridden with
899 <option>--log-target=</option>.</para></listitem>
903 <term><varname>$SYSTEMD_LOG_COLOR</varname></term>
904 <listitem><para>Controls whether systemd highlights important
905 log messages. This can be overridden with
906 <option>--log-color=</option>.</para></listitem>
910 <term><varname>$SYSTEMD_LOG_LOCATION</varname></term>
911 <listitem><para>Controls whether systemd prints the code
912 location along with log messages. This can be overridden with
913 <option>--log-location=</option>.</para></listitem>
917 <term><varname>$XDG_CONFIG_HOME</varname></term>
918 <term><varname>$XDG_CONFIG_DIRS</varname></term>
919 <term><varname>$XDG_DATA_HOME</varname></term>
920 <term><varname>$XDG_DATA_DIRS</varname></term>
922 <listitem><para>The systemd user manager uses these variables
923 in accordance to the <ulink
924 url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
925 Base Directory specification</ulink> to find its
926 configuration.</para></listitem>
930 <term><varname>$SYSTEMD_UNIT_PATH</varname></term>
932 <listitem><para>Controls where systemd looks for unit
933 files.</para></listitem>
937 <term><varname>$SYSTEMD_SYSVINIT_PATH</varname></term>
939 <listitem><para>Controls where systemd looks for SysV init
940 scripts.</para></listitem>
944 <term><varname>$SYSTEMD_SYSVRCND_PATH</varname></term>
946 <listitem><para>Controls where systemd looks for SysV init
947 script runlevel link farms.</para></listitem>
951 <term><varname>$SYSTEMD_COLORS</varname></term>
953 <listitem><para>The value must be a boolean. Controls whether colorized output should be
954 generated. This can be specified to override the decision that <command>systemd</command>
955 makes based on <varname>$TERM</varname> and what the console is connected to.</para>
960 <term><varname>$SYSTEMD_URLIFY</varname></term>
962 <listitem><para>The value must be a boolean. Controls whether clickable links should be generated in the output
963 for terminal emulators supporting this. This can be specified to override the decision that
964 <command>systemd</command> makes based on <varname>$TERM</varname> and other conditions.</para>
969 <term><varname>$LISTEN_PID</varname></term>
970 <term><varname>$LISTEN_FDS</varname></term>
971 <term><varname>$LISTEN_FDNAMES</varname></term>
973 <listitem><para>Set by systemd for supervised processes during
974 socket-based activation. See
975 <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
976 for more information.</para></listitem>
980 <term><varname>$NOTIFY_SOCKET</varname></term>
982 <listitem><para>Set by systemd for supervised processes for
983 status and start-up completion notification. See
984 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
985 for more information.</para></listitem>
991 <!-- 0 /// The whole kernel section is unneeded in elogind
993 <title>Kernel Command Line</title>
995 <para>When run as system instance systemd parses a number of
996 kernel command line arguments<footnote><para>If run inside a Linux
997 container these arguments may be passed as command line arguments
998 to systemd itself, next to any of the command line options listed
999 in the Options section above. If run outside of Linux containers,
1000 these arguments are parsed from <filename>/proc/cmdline</filename>
1001 instead.</para></footnote>:</para>
1003 <variablelist class='kernel-commandline-options'>
1005 <term><varname>systemd.unit=</varname></term>
1006 <term><varname>rd.systemd.unit=</varname></term>
1008 <listitem><para>Overrides the unit to activate on boot.
1009 Defaults to <filename>default.target</filename>. This may be
1010 used to temporarily boot into a different boot unit, for
1011 example <filename>rescue.target</filename> or
1012 <filename>emergency.service</filename>. See
1013 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
1014 for details about these units. The option prefixed with
1015 <literal>rd.</literal> is honored only in the initial RAM disk
1016 (initrd), while the one that is not prefixed only in the main
1017 system.</para></listitem>
1021 <term><varname>systemd.dump_core</varname></term>
1023 <listitem><para>Takes a boolean argument or enables the option if specified
1024 without an argument. If enabled, the systemd manager (PID 1) dumps core when
1025 it crashes. Otherwise, no core dump is created. Defaults to enabled.</para>
1030 <term><varname>systemd.crash_chvt</varname></term>
1032 <listitem><para>Takes a positive integer, or a boolean argument. Can be also
1033 specified without an argument, with the same effect as a positive boolean. If
1034 a positive integer (in the range 1–63) is specified, the system manager (PID
1035 1) will activate the specified virtual terminal (VT) when it
1036 crashes. Defaults to disabled, meaning that no such switch is attempted. If
1037 set to enabled, the VT the kernel messages are written to is selected.
1042 <term><varname>systemd.crash_shell</varname></term>
1044 <listitem><para>Takes a boolean argument or enables the option if specified
1045 without an argument. If enabled, the system manager (PID 1) spawns a shell
1046 when it crashes, after a 10s delay. Otherwise, no shell is spawned. Defaults
1047 to disabled, for security reasons, as the shell is not protected by password
1048 authentication.</para></listitem>
1052 <term><varname>systemd.crash_reboot</varname></term>
1054 <listitem><para>Takes a boolean argument or enables the option if specified
1055 without an argument. If enabled, the system manager (PID 1) will reboot the
1056 machine automatically when it crashes, after a 10s delay. Otherwise, the
1057 system will hang indefinitely. Defaults to disabled, in order to avoid a
1058 reboot loop. If combined with <varname>systemd.crash_shell</varname>, the
1059 system is rebooted after the shell exits.</para></listitem>
1063 <term><varname>systemd.confirm_spawn</varname></term>
1065 <listitem><para>Takes a boolean argument or a path to the virtual console
1066 where the confirmation messages should be emitted. Can be also specified
1067 without an argument, with the same effect as a positive boolean. If enabled,
1068 the system manager (PID 1) asks for confirmation when spawning processes
1069 using <option>/dev/console</option>. If a path or a console name (such as
1070 <literal>ttyS0</literal>) is provided, the virtual console pointed to by this
1071 path or described by the give name will be used instead. Defaults to disabled.
1076 <term><varname>systemd.service_watchdogs=</varname></term>
1078 <listitem><para>Takes a boolean argument. If disabled, all service runtime
1079 watchdogs (<option>WatchdogSec=</option>) and emergency actions (e.g.
1080 <option>OnFailure=</option> or <option>StartLimitAction=</option>) are
1081 ignored by the system manager (PID 1); see
1082 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1083 Defaults to enabled, i.e. watchdogs and failure actions are processed
1084 normally. The hardware watchdog is not affected by this
1085 option.</para></listitem>
1089 <term><varname>systemd.show_status</varname></term>
1091 <listitem><para>Takes a boolean argument or the constant
1092 <constant>auto</constant>. Can be also specified without an argument, with
1093 the same effect as a positive boolean. If enabled, the systemd manager (PID
1094 1) shows terse service status updates on the console during bootup.
1095 <constant>auto</constant> behaves like <option>false</option> until a unit
1096 fails or there is a significant delay in boot. Defaults to enabled, unless
1097 <option>quiet</option> is passed as kernel command line option, in which case
1098 it defaults to <constant>auto</constant>. If specified overrides the system
1099 manager configuration file option <option>ShowStatus=</option>, see
1100 <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
1101 However, the process command line option <option>--show-status=</option>
1102 takes precedence over both this kernel command line option and the
1103 configuration file option.</para></listitem>
1107 <term><varname>systemd.log_target=</varname></term>
1108 <term><varname>systemd.log_level=</varname></term>
1109 <term><varname>systemd.log_location=</varname></term>
1110 <term><varname>systemd.log_color</varname></term>
1112 <listitem><para>Controls log output, with the same effect as the
1113 <varname>$SYSTEMD_LOG_TARGET</varname>,
1114 <varname>$SYSTEMD_LOG_LEVEL</varname>,
1115 <varname>$SYSTEMD_LOG_LOCATION</varname>,
1116 <varname>$SYSTEMD_LOG_COLOR</varname> environment variables described above.
1117 <varname>systemd.log_color</varname> can be specified without an argument,
1118 with the same effect as a positive boolean.</para></listitem>
1122 <term><varname>systemd.default_standard_output=</varname></term>
1123 <term><varname>systemd.default_standard_error=</varname></term>
1124 <listitem><para>Controls default standard output and error
1125 output for services, with the same effect as the
1126 <option>--default-standard-output=</option> and
1127 <option>--default-standard-error=</option> command line
1128 arguments described above, respectively.</para></listitem>
1132 <term><varname>systemd.setenv=</varname></term>
1134 <listitem><para>Takes a string argument in the form
1135 VARIABLE=VALUE. May be used to set default environment
1136 variables to add to forked child processes. May be used more
1137 than once to set multiple variables.</para></listitem>
1141 <term><varname>systemd.machine_id=</varname></term>
1143 <listitem><para>Takes a 32 character hex value to be
1144 used for setting the machine-id. Intended mostly for
1145 network booting where the same machine-id is desired
1146 for every boot.</para></listitem>
1150 <term><varname>systemd.unified_cgroup_hierarchy</varname></term>
1152 <listitem><para>When specified without an argument or with a true argument,
1153 enables the usage of
1154 <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">unified cgroup hierarchy</ulink>
1155 (a.k.a. cgroups-v2). When specified with a false argument, fall back to
1156 hybrid or full legacy cgroup hierarchy.</para>
1158 <para>If this option is not specified, the default behaviour is determined
1159 during compilation (the <option>--with-default-hierarchy=</option>
1160 option). If the kernel does not support unified cgroup hierarchy, the legacy
1161 hierarchy will be used even if this option is specified.</para>
1166 <term><varname>systemd.legacy_systemd_cgroup_controller</varname></term>
1168 <listitem><para>Takes effect if the full unified cgroup hierarchy is not used
1169 (see previous option). When specified without an argument or with a true
1170 argument, disables the use of "hybrid" cgroup hierarchy (i.e. a cgroups-v2
1171 tree used for systemd, and
1172 <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/">legacy
1173 cgroup hierarchy</ulink>, a.k.a. cgroups-v1, for other controllers), and
1174 forces a full "legacy" mode. When specified with a false argument, enables
1175 the use of "hybrid" hierarchy.</para>
1177 <para>If this option is not specified, the default behaviour is determined
1178 during compilation (the <option>--with-default-hierarchy=</option>
1179 option). If the kernel does not support unified cgroup hierarchy, the legacy
1180 hierarchy will be used even if this option is specified.</para>
1185 <term><varname>quiet</varname></term>
1187 <listitem><para>Turn off status output at boot, much like
1188 <varname>systemd.show_status=false</varname> would. Note that
1189 this option is also read by the kernel itself and disables
1190 kernel log output. Passing this option hence turns off the
1191 usual output from both the system manager and the kernel.
1196 <term><varname>debug</varname></term>
1198 <listitem><para>Turn on debugging output. This is equivalent
1199 to <varname>systemd.log_level=debug</varname>. Note that this
1200 option is also read by the kernel itself and enables kernel
1201 debug output. Passing this option hence turns on the debug
1202 output from both the system manager and the
1203 kernel.</para></listitem>
1207 <term><varname>emergency</varname></term>
1208 <term><varname>rd.emergency</varname></term>
1209 <term><varname>-b</varname></term>
1211 <listitem><para>Boot into emergency mode. This is equivalent
1212 to <varname>systemd.unit=emergency.target</varname> or
1213 <varname>rd.systemd.unit=emergency.target</varname>, respectively, and
1214 provided for compatibility reasons and to be easier to type.</para></listitem>
1218 <term><varname>rescue</varname></term>
1219 <term><varname>rd.rescue</varname></term>
1220 <term><varname>single</varname></term>
1221 <term><varname>s</varname></term>
1222 <term><varname>S</varname></term>
1223 <term><varname>1</varname></term>
1225 <listitem><para>Boot into rescue mode. This is equivalent to
1226 <varname>systemd.unit=rescue.target</varname> or
1227 <varname>rd.systemd.unit=rescue.target</varname>, respectively, and
1228 provided for compatibility reasons and to be easier to type.</para></listitem>
1232 <term><varname>2</varname></term>
1233 <term><varname>3</varname></term>
1234 <term><varname>4</varname></term>
1235 <term><varname>5</varname></term>
1237 <listitem><para>Boot into the specified legacy SysV runlevel.
1238 These are equivalent to
1239 <varname>systemd.unit=runlevel2.target</varname>,
1240 <varname>systemd.unit=runlevel3.target</varname>,
1241 <varname>systemd.unit=runlevel4.target</varname>, and
1242 <varname>systemd.unit=runlevel5.target</varname>,
1243 respectively, and provided for compatibility reasons and to be
1244 easier to type.</para></listitem>
1248 <term><varname>locale.LANG=</varname></term>
1249 <term><varname>locale.LANGUAGE=</varname></term>
1250 <term><varname>locale.LC_CTYPE=</varname></term>
1251 <term><varname>locale.LC_NUMERIC=</varname></term>
1252 <term><varname>locale.LC_TIME=</varname></term>
1253 <term><varname>locale.LC_COLLATE=</varname></term>
1254 <term><varname>locale.LC_MONETARY=</varname></term>
1255 <term><varname>locale.LC_MESSAGES=</varname></term>
1256 <term><varname>locale.LC_PAPER=</varname></term>
1257 <term><varname>locale.LC_NAME=</varname></term>
1258 <term><varname>locale.LC_ADDRESS=</varname></term>
1259 <term><varname>locale.LC_TELEPHONE=</varname></term>
1260 <term><varname>locale.LC_MEASUREMENT=</varname></term>
1261 <term><varname>locale.LC_IDENTIFICATION=</varname></term>
1263 <listitem><para>Set the system locale to use. This overrides
1264 the settings in <filename>/etc/locale.conf</filename>. For
1265 more information, see
1266 <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1268 <citerefentry project='man-pages'><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
1273 <para>For other kernel command line parameters understood by
1274 components of the core OS, please refer to
1275 <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
1279 <!-- 0 /// The whole sockets section is unneeded in elogind
1281 <title>Sockets and FIFOs</title>
1285 <term><filename>/run/systemd/notify</filename></term>
1287 <listitem><para>Daemon status notification socket. This is an
1288 <constant>AF_UNIX</constant> datagram socket and is used to
1289 implement the daemon notification logic as implemented by
1290 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
1295 <term><filename>/run/systemd/private</filename></term>
1297 <listitem><para>Used internally as communication channel
1299 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1300 and the systemd process. This is an
1301 <constant>AF_UNIX</constant> stream socket. This interface is
1302 private to systemd and should not be used in external
1303 projects.</para></listitem>
1307 <term><filename>/dev/initctl</filename></term>
1309 <listitem><para>Limited compatibility support for the SysV
1310 client interface, as implemented by the
1311 <filename>systemd-initctl.service</filename> unit. This is a
1312 named pipe in the file system. This interface is obsolete and
1313 should not be used in new applications.</para></listitem>
1320 <title>See Also</title>
1322 <!-- 0 /// elogind does not have that much to see also...
1323 The <ulink url="https://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>,
1324 <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1325 <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1326 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1327 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1328 <citerefentry><refentrytitle>systemd-notify</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1329 <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1330 <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
1331 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1332 <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1333 <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1334 <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1335 <citerefentry project='man-pages'><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1336 <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
1338 The <ulink url="https://github.com/elogind/elogind/">elogind Homepage</ulink>,
1339 <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1340 <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1341 <citerefentry><refentrytitle>pam_elogind</refentrytitle><manvolnum>8</manvolnum></citerefentry>