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SYSTEMD(1)                          systemdSYSTEMD(1)NAME       systemd, init - systemd system and service managerSYNOPSIS       /lib/systemd/systemd [OPTIONS...]       init [OPTIONS...] {COMMAND}DESCRIPTION       systemd is a system and service manager for Linux operating systems.       When run as first process on boot (as PID 1), it acts as init system       that brings up and maintains userspace services. Separate instances are       started for logged-in users to start their services.       systemd is usually not invoked directly by the user, but is installed       as the /sbin/init symlink and started during early boot. The user       manager instances are started automatically through the       user@.service(5) service.       For compatibility with SysV, if the binary is called as init and is not       the first process on the machine (PID is not 1), it will execute       telinit and pass all command line arguments unmodified. That means init       and telinit are mostly equivalent when invoked from normal login       sessions. Seetelinit(8) for more information.       When run as a system instance, systemd interprets the configuration       file system.conf and the files in system.conf.d directories; when run       as a user instance, systemd interprets the configuration file user.conf       and the files in user.conf.d directories. Seesystemd-system.conf(5)       for more information.CONCEPTS       systemd provides a dependency system between various entities called       "units" of 11 different types. Units encapsulate various objects that       are relevant for system boot-up and maintenance. The majority of units       are configured in unit configuration files, whose syntax and basic set       of options is described insystemd.unit(5), however some are created       automatically from other configuration, dynamically from system state       or programmatically at runtime. Units may be "active" (meaning started,       bound, plugged in, ..., depending on the unit type, see below), or       "inactive" (meaning stopped, unbound, unplugged, ...), as well as in       the process of being activated or deactivated, i.e. between the two       states (these states are called "activating", "deactivating"). A       special "failed" state is available as well, which is very similar to       "inactive" and is entered when the service failed in some way (process       returned error code on exit, or crashed, an operation timed out, or       after too many restarts). If this state is entered, the cause will be       logged, for later reference. Note that the various unit types may have       a number of additional substates, which are mapped to the five       generalized unit states described here.       The following unit types are available:        1. Service units, which start and control daemons and the processes           they consist of. For details, seesystemd.service(5).        2. Socket units, which encapsulate local IPC or network sockets in the           system, useful for socket-based activation. For details about           socket units, seesystemd.socket(5), for details on socket-based           activation and other forms of activation, seedaemon(7).        3. Target units are useful to group units, or provide well-known           synchronization points during boot-up, seesystemd.target(5).        4. Device units expose kernel devices in systemd and may be used to           implement device-based activation. For details, seesystemd.device(5).        5. Mount units control mount points in the file system, for details           seesystemd.mount(5).        6. Automount units provide automount capabilities, for on-demand           mounting of file systems as well as parallelized boot-up. Seesystemd.automount(5).        7. Timer units are useful for triggering activation of other units           based on timers. You may find details insystemd.timer(5).        8. Swap units are very similar to mount units and encapsulate memory           swap partitions or files of the operating system. They are           described insystemd.swap(5).        9. Path units may be used to activate other services when file system           objects change or are modified. Seesystemd.path(5).       10. Slice units may be used to group units which manage system           processes (such as service and scope units) in a hierarchical tree           for resource management purposes. Seesystemd.slice(5).       11. Scope units are similar to service units, but manage foreign           processes instead of starting them as well. Seesystemd.scope(5).       Units are named as their configuration files. Some units have special       semantics. A detailed list is available insystemd.special(7).       systemd knows various kinds of dependencies, including positive and       negative requirement dependencies (i.e.  Requires= and Conflicts=) as       well as ordering dependencies (After= and Before=). NB: ordering and       requirement dependencies are orthogonal. If only a requirement       dependency exists between two units (e.g.  foo.service requires       bar.service), but no ordering dependency (e.g.  foo.service after       bar.service) and both are requested to start, they will be started in       parallel. It is a common pattern that both requirement and ordering       dependencies are placed between two units. Also note that the majority       of dependencies are implicitly created and maintained by systemd. In       most cases, it should be unnecessary to declare additional dependencies       manually, however it is possible to do this.       Application programs and units (via dependencies) may request state       changes of units. In systemd, these requests are encapsulated as 'jobs'       and maintained in a job queue. Jobs may succeed or can fail, their       execution is ordered based on the ordering dependencies of the units       they have been scheduled for.       On boot systemd activates the target unit default.target whose job is       to activate on-boot services and other on-boot units by pulling them in       via dependencies. Usually, the unit name is just an alias (symlink) for       either graphical.target (for fully-featured boots into the UI) or       multi-user.target (for limited console-only boots for use in embedded       or server environments, or similar; a subset of graphical.target).       However, it is at the discretion of the administrator to configure it       as an alias to any other target unit. Seesystemd.special(7) for       details about these target units.       systemd only keeps a minimal set of units loaded into memory.       Specifically, the only units that are kept loaded into memory are those       for which at least one of the following conditions is true:        1. It is in an active, activating, deactivating or failed state (i.e.           in any unit state except for "inactive")        2. It has a job queued for it        3. It is a dependency of some sort of at least one other unit that is           loaded into memory        4. It has some form of resource still allocated (e.g. a service unit           that is inactive but for which a process is still lingering that           ignored the request to be terminated)        5. It has been pinned into memory programmatically by a D-Bus call       systemd will automatically and implicitly load units from disk -- if       they are not loaded yet -- as soon as operations are requested for       them. Thus, in many respects, the fact whether a unit is loaded or not       is invisible to clients. Use systemctl list-units --all to       comprehensively list all units currently loaded. Any unit for which       none of the conditions above applies is promptly unloaded. Note that       when a unit is unloaded from memory its accounting data is flushed out       too. However, this data is generally not lost, as a journal log record       is generated declaring the consumed resources whenever a unit shuts       down.       Processes systemd spawns are placed in individual Linux control groups       named after the unit which they belong to in the private systemd       hierarchy. (see cgroups.txt[1] for more information about control       groups, or short "cgroups"). systemd uses this to effectively keep       track of processes. Control group information is maintained in the       kernel, and is accessible via the file system hierarchy (beneath       /sys/fs/cgroup/systemd/), or in tools such assystemd-cgls(1) orps(1)       (ps xawf -eo pid,user,cgroup,args is particularly useful to list all       processes and the systemd units they belong to.).       systemd is compatible with the SysV init system to a large degree: SysV       init scripts are supported and simply read as an alternative (though       limited) configuration file format. The SysV /dev/initctl interface is       provided, and compatibility implementations of the various SysV client       tools are available. In addition to that, various established Unix       functionality such as /etc/fstab or the utmp database are supported.       systemd has a minimal transaction system: if a unit is requested to       start up or shut down it will add it and all its dependencies to a       temporary transaction. Then, it will verify if the transaction is       consistent (i.e. whether the ordering of all units is cycle-free). If       it is not, systemd will try to fix it up, and removes non-essential       jobs from the transaction that might remove the loop. Also, systemd       tries to suppress non-essential jobs in the transaction that would stop       a running service. Finally it is checked whether the jobs of the       transaction contradict jobs that have already been queued, and       optionally the transaction is aborted then. If all worked out and the       transaction is consistent and minimized in its impact it is merged with       all already outstanding jobs and added to the run queue. Effectively       this means that before executing a requested operation, systemd will       verify that it makes sense, fixing it if possible, and only failing if       it really cannot work.       Note that transactions are generated independently of a unit's state at       runtime, hence, for example, if a start job is requested on an already       started unit, it will still generate a transaction and wake up any       inactive dependencies (and cause propagation of other jobs as per the       defined relationships). This is because the enqueued job is at the time       of execution compared to the target unit's state and is marked       successful and complete when both satisfy. However, this job also pulls       in other dependencies due to the defined relationships and thus leads       to, in our our example, start jobs for any of those inactive units       getting queued as well.       systemd contains native implementations of various tasks that need to       be executed as part of the boot process. For example, it sets the       hostname or configures the loopback network device. It also sets up and       mounts various API file systems, such as /sys or /proc.       For more information about the concepts and ideas behind systemd,       please refer to the Original Design Document[2].       Note that some but not all interfaces provided by systemd are covered       by the Interface Stability Promise[3].       Units may be generated dynamically at boot and system manager reload       time, for example based on other configuration files or parameters       passed on the kernel command line. For details, seesystemd.generator(7).       Systems which invoke systemd in a container or initrd environment       should implement the Container Interface[4] or initrd Interface[5]       specifications, respectively.DIRECTORIES       System unit directories           The systemd system manager reads unit configuration from various           directories. Packages that want to install unit files shall place           them in the directory returned by pkg-config systemd           --variable=systemdsystemunitdir. Other directories checked are           /usr/local/lib/systemd/system and /lib/systemd/system. User           configuration always takes precedence.  pkg-config systemd           --variable=systemdsystemconfdir returns the path of the system           configuration directory. Packages should alter the content of these           directories only with the enable and disable commands of thesystemctl(1) tool. Full list of directories is provided insystemd.unit(5).       User unit directories           Similar rules apply for the user unit directories. However, here           the XDG Base Directory specification[6] is followed to find units.           Applications should place their unit files in the directory           returned by pkg-config systemd --variable=systemduserunitdir.           Global configuration is done in the directory reported by           pkg-config systemd --variable=systemduserconfdir. The enable and           disable commands of thesystemctl(1) tool can handle both global           (i.e. for all users) and private (for one user) enabling/disabling           of units. Full list of directories is provided insystemd.unit(5).       SysV init scripts directory           The location of the SysV init script directory varies between           distributions. If systemd cannot find a native unit file for a           requested service, it will look for a SysV init script of the same           name (with the .service suffix removed).       SysV runlevel link farm directory           The location of the SysV runlevel link farm directory varies           between distributions. systemd will take the link farm into account           when figuring out whether a service shall be enabled. Note that a           service unit with a native unit configuration file cannot be           started by activating it in the SysV runlevel link farm.SIGNALS       SIGTERM           Upon receiving this signal the systemd system manager serializes           its state, reexecutes itself and deserializes the saved state           again. This is mostly equivalent to systemctl daemon-reexec.           systemd user managers will start the exit.target unit when this           signal is received. This is mostly equivalent to systemctl --user           start exit.target --job-mode=replace-irreversibly.       SIGINT           Upon receiving this signal the systemd system manager will start           the ctrl-alt-del.target unit. This is mostly equivalent to           systemctl start ctrl-alt-del.target           --job-mode=replace-irreversibly. If this signal is received more           than 7 times per 2s, an immediate reboot is triggered. Note that           pressing Ctrl+Alt+Del on the console will trigger this signal.           Hence, if a reboot is hanging, pressing Ctrl+Alt+Del more than 7           times in 2 seconds is a relatively safe way to trigger an immediate           reboot.           systemd user managers treat this signal the same way as SIGTERM.       SIGWINCH           When this signal is received the systemd system manager will start           the kbrequest.target unit. This is mostly equivalent to systemctl           start kbrequest.target.           This signal is ignored by systemd user managers.       SIGPWR           When this signal is received the systemd manager will start the           sigpwr.target unit. This is mostly equivalent to systemctl start           sigpwr.target.       SIGUSR1           When this signal is received the systemd manager will try to           reconnect to the D-Bus bus.       SIGUSR2           When this signal is received the systemd manager will log its           complete state in human-readable form. The data logged is the same           as printed by systemd-analyze dump.       SIGHUP           Reloads the complete daemon configuration. This is mostly           equivalent to systemctl daemon-reload.       SIGRTMIN+0           Enters default mode, starts the default.target unit. This is mostly           equivalent to systemctl isolate default.target.       SIGRTMIN+1           Enters rescue mode, starts the rescue.target unit. This is mostly           equivalent to systemctl isolate rescue.target.       SIGRTMIN+2           Enters emergency mode, starts the emergency.service unit. This is           mostly equivalent to systemctl isolate emergency.service.       SIGRTMIN+3           Halts the machine, starts the halt.target unit. This is mostly           equivalent to systemctl start halt.target           --job-mode=replace-irreversibly.       SIGRTMIN+4           Powers off the machine, starts the poweroff.target unit. This is           mostly equivalent to systemctl start poweroff.target           --job-mode=replace-irreversibly.       SIGRTMIN+5           Reboots the machine, starts the reboot.target unit. This is mostly           equivalent to systemctl start reboot.target           --job-mode=replace-irreversibly.       SIGRTMIN+6           Reboots the machine via kexec, starts the kexec.target unit. This           is mostly equivalent to systemctl start kexec.target           --job-mode=replace-irreversibly.       SIGRTMIN+13           Immediately halts the machine.       SIGRTMIN+14           Immediately powers off the machine.       SIGRTMIN+15           Immediately reboots the machine.       SIGRTMIN+16           Immediately reboots the machine with kexec.       SIGRTMIN+20           Enables display of status messages on the console, as controlled           via systemd.show_status=1 on the kernel command line.       SIGRTMIN+21           Disables display of status messages on the console, as controlled           via systemd.show_status=0 on the kernel command line.       SIGRTMIN+22           Sets the service manager's log level to "debug", in a fashion           equivalent to systemd.log_level=debug on the kernel command line.       SIGRTMIN+23           Restores the log level to its configured value. The configured           value is derived from - in order of priority - the value specified           with systemd.log-level= on the kernel command line, or the value           specified with LogLevel= in the configuration file, or the built-in           default of "info".       SIGRTMIN+24           Immediately exits the manager (only available for --user           instances).       SIGRTMIN+26           Restores the log target to its configured value. The configured           value is derived from - in order of priority - the value specified           with systemd.log-target= on the kernel command line, or the value           specified with LogTarget= in the configuration file, or the           built-in default.       SIGRTMIN+27, SIGRTMIN+28           Sets the log target to "console" on SIGRTMIN+27 (or "kmsg" on           SIGRTMIN+28), in a fashion equivalent to systemd.log_target=console           (or systemd.log_target=kmsg on SIGRTMIN+28) on the kernel command           line.ENVIRONMENT       $SYSTEMD_LOG_LEVEL           systemd reads the log level from this environment variable. This           can be overridden with --log-level=.       $SYSTEMD_LOG_TARGET           systemd reads the log target from this environment variable. This           can be overridden with --log-target=.       $SYSTEMD_LOG_COLOR           Controls whether systemd highlights important log messages. This           can be overridden with --log-color=.       $SYSTEMD_LOG_LOCATION           Controls whether systemd prints the code location along with log           messages. This can be overridden with --log-location=.       $XDG_CONFIG_HOME, $XDG_CONFIG_DIRS, $XDG_DATA_HOME, $XDG_DATA_DIRS           The systemd user manager uses these variables in accordance to the           XDG Base Directory specification[6] to find its configuration.       $SYSTEMD_UNIT_PATH           Controls where systemd looks for unit files.       $SYSTEMD_SYSVINIT_PATH           Controls where systemd looks for SysV init scripts.       $SYSTEMD_SYSVRCND_PATH           Controls where systemd looks for SysV init script runlevel link           farms.       $SYSTEMD_PAGER           Pager to use when --no-pager is not given; overrides $PAGER. If           neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known           pager implementations are tried in turn, includingless(1) andmore(1), until one is found. If no pager implementation is           discovered no pager is invoked. Setting this environment variable           to an empty string or the value "cat" is equivalent to passing           --no-pager.       $SYSTEMD_LESS           Override the options passed to less (by default "FRSXMK").           Users might want to change two options in particular:           K               This option instructs the pager to exit immediately when Ctrl+C               is pressed. To allow less to handle Ctrl+C itself to switch               back to the pager command prompt, unset this option.               If the value of $SYSTEMD_LESS does not include "K", and the               pager that is invoked is less, Ctrl+C will be ignored by the               executable, and needs to be handled by the pager.           X               This option instructs the pager to not send termcap               initialization and deinitialization strings to the terminal. It               is set by default to allow command output to remain visible in               the terminal even after the pager exits. Nevertheless, this               prevents some pager functionality from working, in particular               paged output cannot be scrolled with the mouse.           Seeless(1) for more discussion.       $SYSTEMD_LESSCHARSET           Override the charset passed to less (by default "utf-8", if the           invoking terminal is determined to be UTF-8 compatible).       $SYSTEMD_COLORS           The value must be a boolean. Controls whether colorized output           should be generated. This can be specified to override the decision           that systemd makes based on $TERM and what the console is connected           to.       $SYSTEMD_URLIFY           The value must be a boolean. Controls whether clickable links           should be generated in the output for terminal emulators supporting           this. This can be specified to override the decision that systemd           makes based on $TERM and other conditions.       $LISTEN_PID, $LISTEN_FDS, $LISTEN_FDNAMES           Set by systemd for supervised processes during socket-based           activation. Seesd_listen_fds(3) for more information.       $NOTIFY_SOCKET           Set by systemd for supervised processes for status and start-up           completion notification. Seesd_notify(3) for more information.       For further environment variables understood by systemd and its various       components, see Known Environment Variables[7].KERNEL COMMAND LINE       When run as the system instance systemd parses a number of options       listed below. They can be specified as kernel command line       arguments[8], or through the "SystemdOptions" EFI variable (on EFI       systems). The kernel command line has higher priority. Following       variables are understood:       systemd.unit=, rd.systemd.unit=           Overrides the unit to activate on boot. Defaults to default.target.           This may be used to temporarily boot into a different boot unit,           for example rescue.target or emergency.service. Seesystemd.special(7) for details about these units. The option           prefixed with "rd."  is honored only in the initial RAM disk           (initrd), while the one that is not prefixed only in the main           system.       systemd.dump_core           Takes a boolean argument or enables the option if specified without           an argument. If enabled, the systemd manager (PID 1) dumps core           when it crashes. Otherwise, no core dump is created. Defaults to           enabled.       systemd.crash_chvt           Takes a positive integer, or a boolean argument. Can be also           specified without an argument, with the same effect as a positive           boolean. If a positive integer (in the range 1-63) is specified,           the system manager (PID 1) will activate the specified virtual           terminal (VT) when it crashes. Defaults to disabled, meaning that           no such switch is attempted. If set to enabled, the VT the kernel           messages are written to is selected.       systemd.crash_shell           Takes a boolean argument or enables the option if specified without           an argument. If enabled, the system manager (PID 1) spawns a shell           when it crashes, after a 10s delay. Otherwise, no shell is spawned.           Defaults to disabled, for security reasons, as the shell is not           protected by password authentication.       systemd.crash_reboot           Takes a boolean argument or enables the option if specified without           an argument. If enabled, the system manager (PID 1) will reboot the           machine automatically when it crashes, after a 10s delay.           Otherwise, the system will hang indefinitely. Defaults to disabled,           in order to avoid a reboot loop. If combined with           systemd.crash_shell, the system is rebooted after the shell exits.       systemd.confirm_spawn           Takes a boolean argument or a path to the virtual console where the           confirmation messages should be emitted. Can be also specified           without an argument, with the same effect as a positive boolean. If           enabled, the system manager (PID 1) asks for confirmation when           spawning processes using /dev/console. If a path or a console name           (such as "ttyS0") is provided, the virtual console pointed to by           this path or described by the give name will be used instead.           Defaults to disabled.       systemd.service_watchdogs=           Takes a boolean argument. If disabled, all service runtime           watchdogs (WatchdogSec=) and emergency actions (e.g.  OnFailure= or           StartLimitAction=) are ignored by the system manager (PID 1); seesystemd.service(5). Defaults to enabled, i.e. watchdogs and failure           actions are processed normally. The hardware watchdog is not           affected by this option.       systemd.show_status           Takes a boolean argument or the constants error and auto. Can be           also specified without an argument, with the same effect as a           positive boolean. If enabled, the systemd manager (PID 1) shows           terse service status updates on the console during bootup. With           error, only messages about failures are shown, but boot is           otherwise quiet.  auto behaves like false until there is a           significant delay in boot. Defaults to enabled, unless quiet is           passed as kernel command line option, in which case it defaults to           error. If specified overrides the system manager configuration file           option ShowStatus=, seesystemd-system.conf(5).       systemd.status_unit_format=           Takes either name or description as the value. If name, the system           manager will use unit names in status messages. If specified,           overrides the system manager configuration file option           StatusUnitFormat=, seesystemd-system.conf(5).       systemd.log_target=, systemd.log_level=, systemd.log_location=,       systemd.log_color           Controls log output, with the same effect as the           $SYSTEMD_LOG_TARGET, $SYSTEMD_LOG_LEVEL, $SYSTEMD_LOG_LOCATION,           $SYSTEMD_LOG_COLOR environment variables described above.           systemd.log_color can be specified without an argument, with the           same effect as a positive boolean.       systemd.default_standard_output=, systemd.default_standard_error=           Controls default standard output and error output for services and           sockets. That is, controls the default for StandardOutput= and           StandardError= (seesystemd.exec(5) for details). Takes one of           inherit, null, tty, journal, journal+console, kmsg, kmsg+console.           If the argument is omitted systemd.default-standard-output=           defaults to journal and systemd.default-standard-error= to inherit.       systemd.setenv=           Takes a string argument in the form VARIABLE=VALUE. May be used to           set default environment variables to add to forked child processes.           May be used more than once to set multiple variables.       systemd.machine_id=           Takes a 32 character hex value to be used for setting the           machine-id. Intended mostly for network booting where the same           machine-id is desired for every boot.       systemd.unified_cgroup_hierarchy           When specified without an argument or with a true argument, enables           the usage of unified cgroup hierarchy[9] (a.k.a. cgroups-v2). When           specified with a false argument, fall back to hybrid or full legacy           cgroup hierarchy.           If this option is not specified, the default behaviour is           determined during compilation (the -Ddefault-hierarchy= meson           option). If the kernel does not support unified cgroup hierarchy,           the legacy hierarchy will be used even if this option is specified.       systemd.legacy_systemd_cgroup_controller           Takes effect if the full unified cgroup hierarchy is not used (see           previous option). When specified without an argument or with a true           argument, disables the use of "hybrid" cgroup hierarchy (i.e. a           cgroups-v2 tree used for systemd, and legacy cgroup hierarchy[10],           a.k.a. cgroups-v1, for other controllers), and forces a full           "legacy" mode. When specified with a false argument, enables the           use of "hybrid" hierarchy.           If this option is not specified, the default behaviour is           determined during compilation (the -Ddefault-hierarchy= meson           option). If the kernel does not support unified cgroup hierarchy,           the legacy hierarchy will be used even if this option is specified.       quiet           Turn off status output at boot, much like systemd.show_status=no           would. Note that this option is also read by the kernel itself and           disables kernel log output. Passing this option hence turns off the           usual output from both the system manager and the kernel.       debug           Turn on debugging output. This is equivalent to           systemd.log_level=debug. Note that this option is also read by the           kernel itself and enables kernel debug output. Passing this option           hence turns on the debug output from both the system manager and           the kernel.       emergency, rd.emergency, -b           Boot into emergency mode. This is equivalent to           systemd.unit=emergency.target or rd.systemd.unit=emergency.target,           respectively, and provided for compatibility reasons and to be           easier to type.       rescue, rd.rescue, single, s, S, 1           Boot into rescue mode. This is equivalent to           systemd.unit=rescue.target or rd.systemd.unit=rescue.target,           respectively, and provided for compatibility reasons and to be           easier to type.       2, 3, 4, 5           Boot into the specified legacy SysV runlevel. These are equivalent           to systemd.unit=runlevel2.target, systemd.unit=runlevel3.target,           systemd.unit=runlevel4.target, and systemd.unit=runlevel5.target,           respectively, and provided for compatibility reasons and to be           easier to type.       locale.LANG=, locale.LANGUAGE=, locale.LC_CTYPE=, locale.LC_NUMERIC=,       locale.LC_TIME=, locale.LC_COLLATE=, locale.LC_MONETARY=,       locale.LC_MESSAGES=, locale.LC_PAPER=, locale.LC_NAME=,       locale.LC_ADDRESS=, locale.LC_TELEPHONE=, locale.LC_MEASUREMENT=,       locale.LC_IDENTIFICATION=           Set the system locale to use. This overrides the settings in           /etc/locale.conf. For more information, seelocale.conf(5) andlocale(7).       For other kernel command line parameters understood by components of       the core OS, please refer tokernel-command-line(7).OPTIONS       systemd is only very rarely invoked directly, since it is started early       and is already running by the time users may interact with it.       Normally, tools likesystemctl(1) are used to give commands to the       manager. Since systemd is usually not invoked directly, the options       listed below are mostly useful for debugging and special purposes.   Introspection and debugging options       Those options are used for testing and introspection, and systemd may       be invoked with them at any time:       --dump-configuration-items           Dump understood unit configuration items. This outputs a terse but           complete list of configuration items understood in unit definition           files.       --dump-bus-properties           Dump exposed bus properties. This outputs a terse but complete list           of properties exposed on D-Bus.       --test           Determine the initial start-up transaction (i.e. the list of jobs           enqueued at start-up), dump it and exit -- without actually           executing any of the determined jobs. This option is useful for           debugging only. Note that during regular service manager start-up           additional units not shown by this operation may be started,           because hardware, socket, bus or other kinds of activation might           add additional jobs as the transaction is executed. Use --system to           request the initial transaction of the system service manager (this           is also the implied default), combine with --user to request the           initial transaction of the per-user service manager instead.       --system, --user           When used in conjunction with --test, selects whether to calculate           the initial transaction for the system instance or for a per-user           instance. These options have no effect when invoked without --test,           as during regular (i.e. non---test) invocations the service manager           will automatically detect whether it shall operate in system or           per-user mode, by checking whether the PID it is run as is 1 or           not. Note that it is not supported booting and maintaining a system           with the service manager running in --system mode but with a PID           other than 1.       -h, --help           Print a short help text and exit.       --version           Print a short version string and exit.   Options that duplicate kernel command line settings       Those options correspond directly to options listed above in "Kernel       Command Line". Both forms may be used equivalently for the system       manager, but it is recommended to use the forms listed above in this       context, because they are properly namespaced. When an option is       specified both on the kernel command line, and as a normal command line       argument, the latter has higher precedence.       When systemd is used a user manager, the kernel command line is ignored       and the options described are understood. Nevertheless, systemd is       usually started in this mode through the user@.service(5) service,       which is shared between all users, and it may be more convenient to use       configuration files to modify settings, seesystemd-user.conf(5), or a       drop-in that specifies one of the environment variables listed above in       "Environment, seesystemd.unit(5).       --unit=           Set default unit to activate on startup. If not specified, defaults           to default.target. See systemd.unit= above.       --dump-core           Enable core dumping on crash. This switch has no effect when           running as user instance. Same as systemd.dump_core= above.       --crash-vt=VT           Switch to a specific virtual console (VT) on crash. This switch has           no effect when running as user instance. Same as           systemd.crash_chvt= above (but not the different spelling!).       --crash-shell           Run a shell on crash. This switch has no effect when running as           user instance. See systemd.crash_shell= above.       --crash-reboot           Automatically reboot the system on crash. This switch has no effect           when running as user instance. See systemd.crash_reboot above.       --confirm-spawn           Ask for confirmation when spawning processes. This switch has no           effect when run as user instance. See systemd.confirm_spawn above.       --show-status           Show terse unit status information is shown on the console during           boot-up and shutdown. See systemd.show_status above.       --log-target=           Set log target. See systemd.log_target above.       --log-level=           Set log level. See systemd.log_level above.       --log-color           Highlight important log messages. See systemd.log_color above.       --log-location           Include code location in log messages. See systemd.log_location           above.       --machine-id=           Override the machine-id set on the hard drive. See           systemd.machine_id= above.       --service-watchdogs           Globally enable/disable all service watchdog timeouts and emergency           actions. See systemd.service_watchdogs above.       --default-standard-output=, --default-standard-error=           Sets the default output or error output for all services and           sockets, respectively. See systemd.default_standard_output= and           systemd.default_standard_error= above.SOCKETS AND FIFOS       /run/systemd/notify           Daemon status notification socket. This is an AF_UNIX datagram           socket and is used to implement the daemon notification logic as           implemented bysd_notify(3).       /run/systemd/private           Used internally as communication channel betweensystemctl(1) and           the systemd process. This is an AF_UNIX stream socket. This           interface is private to systemd and should not be used in external           projects.       /dev/initctl           Limited compatibility support for the SysV client interface, as           implemented by the systemd-initctl.service unit. This is a named           pipe in the file system. This interface is obsolete and should not           be used in new applications.SEE ALSO       The systemd Homepage[11],systemd-system.conf(5),locale.conf(5),systemctl(1),journalctl(1),systemd-notify(1),daemon(7), sd-daemon(3),systemd.unit(5),systemd.special(7),pkg-config(1), kernel-command-line(7),bootup(7),systemd.directives(7)NOTES        1. cgroups.txt           https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt        2. Original Design Document           http://0pointer.de/blog/projects/systemd.html        3. Interface Stability Promise           https://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise        4. Container Interface           https://systemd.io/CONTAINER_INTERFACE        5. initrd Interface           https://www.freedesktop.org/wiki/Software/systemd/InitrdInterface        6. XDG Base Directory specification           http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html        7. Known Environment Variables           https://systemd.io/ENVIRONMENT        8. If run inside a Linux container these arguments may be passed as           command line arguments to systemd itself, next to any of the           command line options listed in the Options section above. If run           outside of Linux containers, these arguments are parsed from           /proc/cmdline instead.        9. unified cgroup hierarchy           https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html       10. legacy cgroup hierarchy           https://www.kernel.org/doc/Documentation/cgroup-v1/       11. systemd Homepage           https://www.freedesktop.org/wiki/Software/systemd/systemd 245SYSTEMD(1)