noble (1) systemctl.1.gz

Provided by: systemd_255.4-1ubuntu8.5_amd64 bug

NAME

       systemctl - Control the systemd system and service manager

SYNOPSIS

       systemctl [OPTIONS...] COMMAND [UNIT...]

DESCRIPTION

       systemctl may be used to introspect and control the state of the "systemd" system and service manager.
       Please refer to systemd(1) for an introduction into the basic concepts and functionality this tool
       manages.

COMMANDS

       The following commands are understood:

   Unit Commands (Introspection and Modification)
       list-units [PATTERN...]
           List units that systemd currently has in memory. This includes units that are either referenced
           directly or through a dependency, units that are pinned by applications programmatically, or units
           that were active in the past and have failed. By default only units which are active, have pending
           jobs, or have failed are shown; this can be changed with option --all. If one or more PATTERNs are
           specified, only units matching one of them are shown. The units that are shown are additionally
           filtered by --type= and --state= if those options are specified.

           Note that this command does not show unit templates, but only instances of unit templates. Units
           templates that aren't instantiated are not runnable, and will thus never show up in the output of
           this command. Specifically this means that foo@.service will never be shown in this list — unless
           instantiated, e.g. as foo@bar.service. Use list-unit-files (see below) for listing installed unit
           template files.

           Produces output similar to

                 UNIT                         LOAD   ACTIVE SUB     DESCRIPTION
                 sys-module-fuse.device       loaded active plugged /sys/module/fuse
                 -.mount                      loaded active mounted Root Mount
                 boot-efi.mount               loaded active mounted /boot/efi
                 systemd-journald.service     loaded active running Journal Service
                 systemd-logind.service       loaded active running Login Service
               ● user@1000.service            loaded failed failed  User Manager for UID 1000
                 ...
                 systemd-tmpfiles-clean.timer loaded active waiting Daily Cleanup of Temporary Directories

               LOAD   = Reflects whether the unit definition was properly loaded.
               ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
               SUB    = The low-level unit activation state, values depend on unit type.

               123 loaded units listed. Pass --all to see loaded but inactive units, too.
               To show all installed unit files use 'systemctl list-unit-files'.

           The header and the last unit of a given type are underlined if the terminal supports that. A colored
           dot is shown next to services which were masked, not found, or otherwise failed.

           The LOAD column shows the load state, one of loaded, not-found, bad-setting, error, masked. The
           ACTIVE columns shows the general unit state, one of active, reloading, inactive, failed, activating,
           deactivating. The SUB column shows the unit-type-specific detailed state of the unit, possible values
           vary by unit type. The list of possible LOAD, ACTIVE, and SUB states is not constant and new systemd
           releases may both add and remove values.

               systemctl --state=help

           command may be used to display the current set of possible values.

           This is the default command.

       list-automounts [PATTERN...]
           List automount units currently in memory, ordered by mount path. If one or more PATTERNs are
           specified, only automount units matching one of them are shown. Produces output similar to

               WHAT        WHERE                    MOUNTED IDLE TIMEOUT UNIT
               /dev/sdb1   /mnt/test                no      120s         mnt-test.automount
               binfmt_misc /proc/sys/fs/binfmt_misc yes     0            proc-sys-fs-binfmt_misc.automount

               2 automounts listed.

           Also see --show-types, --all, and --state=.

           Added in version 252.

       list-paths [PATTERN...]
           List path units currently in memory, ordered by path. If one or more PATTERNs are specified, only
           path units matching one of them are shown. Produces output similar to

               PATH                           CONDITION         UNIT                               ACTIVATES
               /run/systemd/ask-password      DirectoryNotEmpty systemd-ask-password-plymouth.path systemd-ask-password-plymouth.service
               /run/systemd/ask-password      DirectoryNotEmpty systemd-ask-password-wall.path     systemd-ask-password-wall.service
               /var/cache/cups/org.cups.cupsd PathExists        cups.path                          cups.service

               3 paths listed.

           Also see --show-types, --all, and --state=.

           Added in version 254.

       list-sockets [PATTERN...]
           List socket units currently in memory, ordered by listening address. If one or more PATTERNs are
           specified, only socket units matching one of them are shown. Produces output similar to

               LISTEN           UNIT                        ACTIVATES
               /dev/initctl     systemd-initctl.socket      systemd-initctl.service
               ...
               [::]:22          sshd.socket                 sshd.service
               kobject-uevent 1 systemd-udevd-kernel.socket systemd-udevd.service

               5 sockets listed.

           Note: because the addresses might contains spaces, this output is not suitable for programmatic
           consumption.

           Also see --show-types, --all, and --state=.

           Added in version 202.

       list-timers [PATTERN...]
           List timer units currently in memory, ordered by the time they elapse next. If one or more PATTERNs
           are specified, only units matching one of them are shown. Produces output similar to

               NEXT                         LEFT          LAST                         PASSED     UNIT                         ACTIVATES
               -                            -             Thu 2017-02-23 13:40:29 EST  3 days ago ureadahead-stop.timer        ureadahead-stop.service
               Sun 2017-02-26 18:55:42 EST  1min 14s left Thu 2017-02-23 13:54:44 EST  3 days ago systemd-tmpfiles-clean.timer systemd-tmpfiles-clean.service
               Sun 2017-02-26 20:37:16 EST  1h 42min left Sun 2017-02-26 11:56:36 EST  6h ago     apt-daily.timer              apt-daily.service
               Sun 2017-02-26 20:57:49 EST  2h 3min left  Sun 2017-02-26 11:56:36 EST  6h ago     snapd.refresh.timer          snapd.refresh.service

           NEXT shows the next time the timer will run.

           LEFT shows how long till the next time the timer runs.

           LAST shows the last time the timer ran.

           PASSED shows how long has passed since the timer last ran.

           UNIT shows the name of the timer

           ACTIVATES shows the name the service the timer activates when it runs.

           Also see --all and --state=.

           Added in version 209.

       is-active PATTERN...
           Check whether any of the specified units are active (i.e. running). Returns an exit code 0 if at
           least one is active, or non-zero otherwise. Unless --quiet is specified, this will also print the
           current unit state to standard output.

       is-failed [PATTERN...]
           Check whether any of the specified units is in the "failed" state. If no unit is specified, check
           whether there are any failed units, which corresponds to the "degraded" state returned by
           is-system-running. Returns an exit code 0 if at least one has failed, non-zero otherwise. Unless
           --quiet is specified, this will also print the current unit or system state to standard output.

           Added in version 197.

       status [PATTERN...|PID...]]
           Show runtime status information about the whole system or about one or more units followed by most
           recent log data from the journal. If no positional arguments are specified, and no unit filter is
           given with --type=, --state=, or --failed, shows the status of the whole system. If combined with
           --all, follows that with the status of all units. If positional arguments are specified, each
           positional argument is treated as either a unit name to show, or a glob pattern to show units whose
           names match that pattern, or a PID to show the unit containing that PID. When --type=, --state=, or
           --failed are used, units are additionally filtered by the TYPE and ACTIVE state.

           This function is intended to generate human-readable output. If you are looking for computer-parsable
           output, use show instead. By default, this function only shows 10 lines of output and ellipsizes
           lines to fit in the terminal window. This can be changed with --lines and --full, see above. In
           addition, journalctl --unit=NAME or journalctl --user-unit=NAME use a similar filter for messages and
           might be more convenient.

           Note that this operation only displays runtime status, i.e. information about the current invocation
           of the unit (if it is running) or the most recent invocation (if it is not running anymore, and has
           not been released from memory). Information about earlier invocations, invocations from previous
           system boots, or prior invocations that have already been released from memory may be retrieved via
           journalctl --unit=.

           systemd implicitly loads units as necessary, so just running the status will attempt to load a file.
           The command is thus not useful for determining if something was already loaded or not. The units may
           possibly also be quickly unloaded after the operation is completed if there's no reason to keep it in
           memory thereafter.

           Example 1. Example output from systemctl status

               $ systemctl status bluetooth
               ● bluetooth.service - Bluetooth service
                  Loaded: loaded (/usr/lib/systemd/system/bluetooth.service; enabled; preset: enabled)
                  Active: active (running) since Wed 2017-01-04 13:54:04 EST; 1 weeks 0 days ago
                    Docs: man:bluetoothd(8)
                Main PID: 930 (bluetoothd)
                  Status: "Running"
                   Tasks: 1
                  Memory: 648.0K
                     CPU: 435ms
                  CGroup: /system.slice/bluetooth.service
                          └─930 /usr/lib/bluetooth/bluetoothd

               Jan 12 10:46:45 example.com bluetoothd[8900]: Not enough free handles to register service
               Jan 12 10:46:45 example.com bluetoothd[8900]: Current Time Service could not be registered
               Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output error (5)

           The dot ("●") uses color on supported terminals to summarize the unit state at a glance. Along with
           its color, its shape varies according to its state: "inactive" or "maintenance" is a white circle
           ("○"), "active" is a green dot ("●"), "deactivating" is a white dot, "failed" or "error" is a red
           cross ("×"), and "reloading" is a green clockwise circle arrow ("↻").

           The "Loaded:" line in the output will show "loaded" if the unit has been loaded into memory. Other
           possible values for "Loaded:" include: "error" if there was a problem loading it, "not-found" if no
           unit file was found for this unit, "bad-setting" if an essential unit file setting could not be
           parsed and "masked" if the unit file has been masked. Along with showing the path to the unit file,
           this line will also show the enablement state. Enabled units are included in the dependency network
           between units, and thus are started at boot or via some other form of activation. See the full table
           of possible enablement states — including the definition of "masked" — in the documentation for the
           is-enabled command.

           The "Active:" line shows active state. The value is usually "active" or "inactive". Active could mean
           started, bound, plugged in, etc depending on the unit type. The unit could also be in process of
           changing states, reporting a state of "activating" or "deactivating". A special "failed" state is
           entered when the service failed in some way, such as a crash, exiting with an error code or timing
           out. If the failed state is entered the cause will be logged for later reference.

       show [PATTERN...|JOB...]
           Show properties of one or more units, jobs, or the manager itself. If no argument is specified,
           properties of the manager will be shown. If a unit name is specified, properties of the unit are
           shown, and if a job ID is specified, properties of the job are shown. By default, empty properties
           are suppressed. Use --all to show those too. To select specific properties to show, use --property=.
           This command is intended to be used whenever computer-parsable output is required. Use status if you
           are looking for formatted human-readable output.

           Many properties shown by systemctl show map directly to configuration settings of the system and
           service manager and its unit files. Note that the properties shown by the command are generally more
           low-level, normalized versions of the original configuration settings and expose runtime state in
           addition to configuration. For example, properties shown for service units include the service's
           current main process identifier as "MainPID" (which is runtime state), and time settings are always
           exposed as properties ending in the "...USec" suffix even if a matching configuration options end in
           "...Sec", because microseconds is the normalized time unit used internally by the system and service
           manager.

           For details about many of these properties, see the documentation of the D-Bus interface backing
           these properties, see org.freedesktop.systemd1(5).

       cat PATTERN...
           Show backing files of one or more units. Prints the "fragment" and "drop-ins" (source files) of
           units. Each file is preceded by a comment which includes the file name. Note that this shows the
           contents of the backing files on disk, which may not match the system manager's understanding of
           these units if any unit files were updated on disk and the daemon-reload command wasn't issued since.

           Added in version 209.

       help PATTERN...|PID...
           Show manual pages for one or more units, if available. If a PID is given, the manual pages for the
           unit the process belongs to are shown.

           Added in version 185.

       list-dependencies [UNIT...]
           Shows units required and wanted by the specified units. This recursively lists units following the
           Requires=, Requisite=, Wants=, ConsistsOf=, BindsTo=, and Upholds= dependencies. If no units are
           specified, default.target is implied.

           The units that are shown are additionally filtered by --type= and --state= if those options are
           specified. Note that we won't be able to use a tree structure in this case, so --plain is implied.

           By default, only target units are recursively expanded. When --all is passed, all other units are
           recursively expanded as well.

           Options --reverse, --after, --before may be used to change what types of dependencies are shown.

           Note that this command only lists units currently loaded into memory by the service manager. In
           particular, this command is not suitable to get a comprehensive list at all reverse dependencies on a
           specific unit, as it won't list the dependencies declared by units currently not loaded.

           Added in version 198.

       start PATTERN...
           Start (activate) one or more units specified on the command line.

           Note that unit glob patterns expand to names of units currently in memory. Units which are not active
           and are not in a failed state usually are not in memory, and will not be matched by any pattern. In
           addition, in case of instantiated units, systemd is often unaware of the instance name until the
           instance has been started. Therefore, using glob patterns with start has limited usefulness. Also,
           secondary alias names of units are not considered.

           Option --all may be used to also operate on inactive units which are referenced by other loaded
           units. Note that this is not the same as operating on "all" possible units, because as the previous
           paragraph describes, such a list is ill-defined. Nevertheless, systemctl start --all GLOB may be
           useful if all the units that should match the pattern are pulled in by some target which is known to
           be loaded.

       stop PATTERN...
           Stop (deactivate) one or more units specified on the command line.

           This command will fail if the unit does not exist or if stopping of the unit is prohibited (see
           RefuseManualStop= in systemd.unit(5)). It will not fail if any of the commands configured to stop the
           unit (ExecStop=, etc.) fail, because the manager will still forcibly terminate the unit.

           If a unit that gets stopped can still be triggered by other units, a warning containing the names of
           the triggering units is shown.  --no-warn can be used to suppress the warning.

       reload PATTERN...
           Asks all units listed on the command line to reload their configuration. Note that this will reload
           the service-specific configuration, not the unit configuration file of systemd. If you want systemd
           to reload the configuration file of a unit, use the daemon-reload command. In other words: for the
           example case of Apache, this will reload Apache's httpd.conf in the web server, not the
           apache.service systemd unit file.

           This command should not be confused with the daemon-reload command.

       restart PATTERN...
           Stop and then start one or more units specified on the command line. If the units are not running
           yet, they will be started.

           Note that restarting a unit with this command does not necessarily flush out all of the unit's
           resources before it is started again. For example, the per-service file descriptor storage facility
           (see FileDescriptorStoreMax= in systemd.service(5)) will remain intact as long as the unit has a job
           pending, and is only cleared when the unit is fully stopped and no jobs are pending anymore. If it is
           intended that the file descriptor store is flushed out, too, during a restart operation an explicit
           systemctl stop command followed by systemctl start should be issued.

       try-restart PATTERN...
           Stop and then start one or more units specified on the command line if the units are running. This
           does nothing if units are not running.

       reload-or-restart PATTERN...
           Reload one or more units if they support it. If not, stop and then start them instead. If the units
           are not running yet, they will be started.

       try-reload-or-restart PATTERN...
           Reload one or more units if they support it. If not, stop and then start them instead. This does
           nothing if the units are not running.

           Added in version 229.

       isolate UNIT
           Start the unit specified on the command line and its dependencies and stop all others, unless they
           have IgnoreOnIsolate=yes (see systemd.unit(5)). If a unit name with no extension is given, an
           extension of ".target" will be assumed.

           This command is dangerous, since it will immediately stop processes that are not enabled in the new
           target, possibly including the graphical environment or terminal you are currently using.

           Note that this operation is allowed only on units where AllowIsolate= is enabled. See systemd.unit(5)
           for details.

       kill PATTERN...
           Send a UNIX process signal to one or more processes of the unit. Use --kill-whom= to select which
           process to send the signal to. Use --signal= to select the signal to send. Combine with --kill-value=
           to enqueue a POSIX Realtime Signal with an associated value.

       clean PATTERN...
           Remove the configuration, state, cache, logs or runtime data of the specified units. Use --what= to
           select which kind of resource to remove. For service units this may be used to remove the directories
           configured with ConfigurationDirectory=, StateDirectory=, CacheDirectory=, LogsDirectory= and
           RuntimeDirectory=, see systemd.exec(5) for details. It may also be used to clear the file descriptor
           store as enabled via FileDescriptorStoreMax=, see systemd.service(5) for details. For timer units
           this may be used to clear out the persistent timestamp data if Persistent= is used and --what=state
           is selected, see systemd.timer(5). This command only applies to units that use either of these
           settings. If --what= is not specified, the cache and runtime data as well as the file descriptor
           store are removed (as these three types of resources are generally redundant and reproducible on the
           next invocation of the unit). Note that the specified units must be stopped to invoke this operation.

           Added in version 243.

       freeze PATTERN...
           Freeze one or more units specified on the command line using cgroup freezer

           Freezing the unit will cause all processes contained within the cgroup corresponding to the unit to
           be suspended. Being suspended means that unit's processes won't be scheduled to run on CPU until
           thawed. Note that this command is supported only on systems that use unified cgroup hierarchy. Unit
           is automatically thawed just before we execute a job against the unit, e.g. before the unit is
           stopped.

           Added in version 246.

       thaw PATTERN...
           Thaw (unfreeze) one or more units specified on the command line.

           This is the inverse operation to the freeze command and resumes the execution of processes in the
           unit's cgroup.

           Added in version 246.

       set-property UNIT PROPERTY=VALUE...
           Set the specified unit properties at runtime where this is supported. This allows changing
           configuration parameter properties such as resource control settings at runtime. Not all properties
           may be changed at runtime, but many resource control settings (primarily those in systemd.resource-
           control(5)) may. The changes are applied immediately, and stored on disk for future boots, unless
           --runtime is passed, in which case the settings only apply until the next reboot. The syntax of the
           property assignment follows closely the syntax of assignments in unit files.

           Example: systemctl set-property foobar.service CPUWeight=200

           If the specified unit appears to be inactive, the changes will be only stored on disk as described
           previously hence they will be effective when the unit will be started.

           Note that this command allows changing multiple properties at the same time, which is preferable over
           setting them individually.

           Example: systemctl set-property foobar.service CPUWeight=200 MemoryMax=2G IPAccounting=yes

           Like with unit file configuration settings, assigning an empty setting usually resets a property to
           its defaults.

           Example: systemctl set-property avahi-daemon.service IPAddressDeny=

           Added in version 206.

       bind UNIT PATH [PATH]
           Bind-mounts a file or directory from the host into the specified unit's mount namespace. The first
           path argument is the source file or directory on the host, the second path argument is the
           destination file or directory in the unit's mount namespace. When the latter is omitted, the
           destination path in the unit's mount namespace is the same as the source path on the host. When
           combined with the --read-only switch, a ready-only bind mount is created. When combined with the
           --mkdir switch, the destination path is first created before the mount is applied.

           Note that this option is currently only supported for units that run within a mount namespace (e.g.:
           with RootImage=, PrivateMounts=, etc.). This command supports bind-mounting directories, regular
           files, device nodes, AF_UNIX socket nodes, as well as FIFOs. The bind mount is ephemeral, and it is
           undone as soon as the current unit process exists. Note that the namespace mentioned here, where the
           bind mount will be added to, is the one where the main service process runs. Other processes (those
           exececuted by ExecReload=, ExecStartPre=, etc.) run in distinct namespaces.

           If supported by the kernel, any prior mount on the selected target will be replaced by the new mount.
           If not supported, any prior mount will be over-mounted, but remain pinned and inaccessible.

           Added in version 248.

       mount-image UNIT IMAGE [PATH [PARTITION_NAME:MOUNT_OPTIONS]]
           Mounts an image from the host into the specified unit's mount namespace. The first path argument is
           the source image on the host, the second path argument is the destination directory in the unit's
           mount namespace (i.e. inside RootImage=/RootDirectory=). The following argument, if any, is
           interpreted as a colon-separated tuple of partition name and comma-separated list of mount options
           for that partition. The format is the same as the service MountImages= setting. When combined with
           the --read-only switch, a ready-only mount is created. When combined with the --mkdir switch, the
           destination path is first created before the mount is applied.

           Note that this option is currently only supported for units that run within a mount namespace (i.e.
           with RootImage=, PrivateMounts=, etc.). Note that the namespace mentioned here where the image mount
           will be added to, is the one where the main service process runs. Note that the namespace mentioned
           here, where the bind mount will be added to, is the one where the main service process runs. Other
           processes (those exececuted by ExecReload=, ExecStartPre=, etc.) run in distinct namespaces.

           If supported by the kernel, any prior mount on the selected target will be replaced by the new mount.
           If not supported, any prior mount will be over-mounted, but remain pinned and inaccessible.

           Example:

               systemctl mount-image foo.service /tmp/img.raw /var/lib/image root:ro,nosuid

               systemctl mount-image --mkdir bar.service /tmp/img.raw /var/lib/baz/img

           Added in version 248.

       service-log-level SERVICE [LEVEL]
           If the LEVEL argument is not given, print the current log level as reported by service SERVICE.

           If the optional argument LEVEL is provided, then change the current log level of the service to
           LEVEL. The log level should be a typical syslog log level, i.e. a value in the range 0...7 or one of
           the strings emerg, alert, crit, err, warning, notice, info, debug; see syslog(3) for details.

           The service must have the appropriate BusName=destination property and also implement the generic
           org.freedesktop.LogControl1(5) interface. (systemctl will use the generic D-Bus protocol to access
           the org.freedesktop.LogControl1.LogLevel interface for the D-Bus name destination.)

           Added in version 247.

       service-log-target SERVICE [TARGET]
           If the TARGET argument is not given, print the current log target as reported by service SERVICE.

           If the optional argument TARGET is provided, then change the current log target of the service to
           TARGET. The log target should be one of the strings console (for log output to the service's standard
           error stream), kmsg (for log output to the kernel log buffer), journal (for log output to systemd-
           journald.service(8) using the native journal protocol), syslog (for log output to the classic syslog
           socket /dev/log), null (for no log output whatsoever) or auto (for an automatically determined
           choice, typically equivalent to console if the service is invoked interactively, and journal or
           syslog otherwise).

           For most services, only a small subset of log targets make sense. In particular, most "normal"
           services should only implement console, journal, and null. Anything else is only appropriate for
           low-level services that are active in very early boot before proper logging is established.

           The service must have the appropriate BusName=destination property and also implement the generic
           org.freedesktop.LogControl1(5) interface. (systemctl will use the generic D-Bus protocol to access
           the org.freedesktop.LogControl1.LogLevel interface for the D-Bus name destination.)

           Added in version 247.

       reset-failed [PATTERN...]
           Reset the "failed" state of the specified units, or if no unit name is passed, reset the state of all
           units. When a unit fails in some way (i.e. process exiting with non-zero error code, terminating
           abnormally or timing out), it will automatically enter the "failed" state and its exit code and
           status is recorded for introspection by the administrator until the service is stopped/re-started or
           reset with this command.

           In addition to resetting the "failed" state of a unit it also resets various other per-unit
           properties: the start rate limit counter of all unit types is reset to zero, as is the restart
           counter of service units. Thus, if a unit's start limit (as configured with
           StartLimitIntervalSec=/StartLimitBurst=) is hit and the unit refuses to be started again, use this
           command to make it startable again.

       whoami [PID...]
           Returns the units the processes referenced by the given PIDs belong to (one per line). If no PID is
           specified returns the unit the systemctl command is invoked in.

           Added in version 254.

   Unit File Commands
       list-unit-files [PATTERN...]
           List unit files installed on the system, in combination with their enablement state (as reported by
           is-enabled). If one or more PATTERNs are specified, only unit files whose name matches one of them
           are shown (patterns matching unit file system paths are not supported).

           Unlike list-units this command will list template units in addition to explicitly instantiated units.

           Added in version 233.

       enable UNIT..., enable PATH...
           Enable one or more units or unit instances. This will create a set of symlinks, as encoded in the
           [Install] sections of the indicated unit files. After the symlinks have been created, the system
           manager configuration is reloaded (in a way equivalent to daemon-reload), in order to ensure the
           changes are taken into account immediately. Note that this does not have the effect of also starting
           any of the units being enabled. If this is desired, combine this command with the --now switch, or
           invoke start with appropriate arguments later. Note that in case of unit instance enablement (i.e.
           enablement of units of the form foo@bar.service), symlinks named the same as instances are created in
           the unit configuration directory, however they point to the single template unit file they are
           instantiated from.

           This command expects either valid unit names (in which case various unit file directories are
           automatically searched for unit files with appropriate names), or absolute paths to unit files (in
           which case these files are read directly). If a specified unit file is located outside of the usual
           unit file directories, an additional symlink is created, linking it into the unit configuration path,
           thus ensuring it is found when requested by commands such as start. The file system where the linked
           unit files are located must be accessible when systemd is started (e.g. anything underneath /home/ or
           /var/ is not allowed, unless those directories are located on the root file system).

           This command will print the file system operations executed. This output may be suppressed by passing
           --quiet.

           Note that this operation creates only the symlinks suggested in the [Install] section of the unit
           files. While this command is the recommended way to manipulate the unit configuration directory, the
           administrator is free to make additional changes manually by placing or removing symlinks below this
           directory. This is particularly useful to create configurations that deviate from the suggested
           default installation. In this case, the administrator must make sure to invoke daemon-reload manually
           as necessary, in order to ensure the changes are taken into account.

           When using this operation on units without install information, a warning about it is shown.
           --no-warn can be used to suppress the warning.

           Enabling units should not be confused with starting (activating) units, as done by the start command.
           Enabling and starting units is orthogonal: units may be enabled without being started and started
           without being enabled. Enabling simply hooks the unit into various suggested places (for example, so
           that the unit is automatically started on boot or when a particular kind of hardware is plugged in).
           Starting actually spawns the daemon process (in case of service units), or binds the socket (in case
           of socket units), and so on.

           Depending on whether --system, --user, --runtime, or --global is specified, this enables the unit for
           the system, for the calling user only, for only this boot of the system, or for all future logins of
           all users. Note that in the last case, no systemd daemon configuration is reloaded.

           Using enable on masked units is not supported and results in an error.

       disable UNIT...
           Disables one or more units. This removes all symlinks to the unit files backing the specified units
           from the unit configuration directory, and hence undoes any changes made by enable or link. Note that
           this removes all symlinks to matching unit files, including manually created symlinks, and not just
           those actually created by enable or link. Note that while disable undoes the effect of enable, the
           two commands are otherwise not symmetric, as disable may remove more symlinks than a prior enable
           invocation of the same unit created.

           This command expects valid unit names only, it does not accept paths to unit files.

           In addition to the units specified as arguments, all units are disabled that are listed in the Also=
           setting contained in the [Install] section of any of the unit files being operated on.

           This command implicitly reloads the system manager configuration after completing the operation. Note
           that this command does not implicitly stop the units that are being disabled. If this is desired,
           either combine this command with the --now switch, or invoke the stop command with appropriate
           arguments later.

           This command will print information about the file system operations (symlink removals) executed.
           This output may be suppressed by passing --quiet.

           If a unit gets disabled but its triggering units are still active, a warning containing the names of
           the triggering units is shown.  --no-warn can be used to suppress the warning.

           When this command is used with --user, the units being operated on might still be enabled in global
           scope, and thus get started automatically even after a successful disablement in user scope. In this
           case, a warning about it is shown, which can be suppressed using --no-warn.

           This command honors --system, --user, --runtime, --global and --no-warn in a similar way as enable.

           Added in version 238.

       reenable UNIT...
           Reenable one or more units, as specified on the command line. This is a combination of disable and
           enable and is useful to reset the symlinks a unit file is enabled with to the defaults configured in
           its [Install] section. This command expects a unit name only, it does not accept paths to unit files.

           Added in version 238.

       preset UNIT...
           Reset the enable/disable status one or more unit files, as specified on the command line, to the
           defaults configured in the preset policy files. This has the same effect as disable or enable,
           depending how the unit is listed in the preset files.

           Use --preset-mode= to control whether units shall be enabled and disabled, or only enabled, or only
           disabled.

           If the unit carries no install information, it will be silently ignored by this command.  UNIT must
           be the real unit name, any alias names are ignored silently.

           For more information on the preset policy format, see systemd.preset(5).

           Added in version 238.

       preset-all
           Resets all installed unit files to the defaults configured in the preset policy file (see above).

           Use --preset-mode= to control whether units shall be enabled and disabled, or only enabled, or only
           disabled.

           Added in version 215.

       is-enabled UNIT...
           Checks whether any of the specified unit files are enabled (as with enable). Returns an exit code of
           0 if at least one is enabled, non-zero otherwise. Prints the current enable status (see table). To
           suppress this output, use --quiet. To show installation targets, use --full.

           Table 1.  is-enabled output
           ┌──────────────────┬──────────────────────────────┬───────────┐
           │NameDescriptionExit Code │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"enabled"         │ Enabled via .wants/,         │           │
           ├──────────────────┤ .requires/ or Alias=         │           │
           │"enabled-runtime" │ symlinks (permanently in     │ 0         │
           │                  │ /etc/systemd/system/, or     │           │
           │                  │ transiently in               │           │
           │                  │ /run/systemd/system/).       │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"linked"          │ Made available through one   │           │
           ├──────────────────┤ or more symlinks to the unit │           │
           │"linked-runtime"  │ file (permanently in         │           │
           │                  │ /etc/systemd/system/ or      │           │
           │                  │ transiently in               │ > 0       │
           │                  │ /run/systemd/system/), even  │           │
           │                  │ though the unit file might   │           │
           │                  │ reside outside of the unit   │           │
           │                  │ file search path.            │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"alias"           │ The name is an alias         │ 0         │
           │                  │ (symlink to another unit     │           │
           │                  │ file).                       │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"masked"          │ Completely disabled, so that │           │
           ├──────────────────┤ any start operation on it    │           │
           │"masked-runtime"  │ fails (permanently in        │ > 0       │
           │                  │ /etc/systemd/system/ or      │           │
           │                  │ transiently in               │           │
           │                  │ /run/systemd/systemd/).      │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"static"          │ The unit file is not         │ 0         │
           │                  │ enabled, and has no          │           │
           │                  │ provisions for enabling in   │           │
           │                  │ the [Install] unit file      │           │
           │                  │ section.                     │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"indirect"        │ The unit file itself is not  │ 0         │
           │                  │ enabled, but it has a        │           │
           │                  │ non-empty Also= setting in   │           │
           │                  │ the [Install] unit file      │           │
           │                  │ section, listing other unit  │           │
           │                  │ files that might be enabled, │           │
           │                  │ or it has an alias under a   │           │
           │                  │ different name through a     │           │
           │                  │ symlink that is not          │           │
           │                  │ specified in Also=. For      │           │
           │                  │ template unit files, an      │           │
           │                  │ instance different than the  │           │
           │                  │ one specified in             │           │
           │                  │ DefaultInstance= is enabled. │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"disabled"        │ The unit file is not         │ > 0       │
           │                  │ enabled, but contains an     │           │
           │                  │ [Install] section with       │           │
           │                  │ installation instructions.   │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"generated"       │ The unit file was generated  │ 0         │
           │                  │ dynamically via a generator  │           │
           │                  │ tool. See                    │           │
           │                  │ systemd.generator(7).        │           │
           │                  │ Generated unit files may not │           │
           │                  │ be enabled, they are enabled │           │
           │                  │ implicitly by their          │           │
           │                  │ generator.                   │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"transient"       │ The unit file has been       │ 0         │
           │                  │ created dynamically with the │           │
           │                  │ runtime API. Transient units │           │
           │                  │ may not be enabled.          │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"bad"             │ The unit file is invalid or  │ > 0       │
           │                  │ another error occurred. Note │           │
           │                  │ that is-enabled will not     │           │
           │                  │ actually return this state,  │           │
           │                  │ but print an error message   │           │
           │                  │ instead. However the unit    │           │
           │                  │ file listing printed by      │           │
           │                  │ list-unit-files might show   │           │
           │                  │ it.                          │           │
           ├──────────────────┼──────────────────────────────┼───────────┤
           │"not-found"       │ The unit file doesn't exist. │ 4         │
           └──────────────────┴──────────────────────────────┴───────────┘
           Added in version 238.

       mask UNIT...
           Mask one or more units, as specified on the command line. This will link these unit files to
           /dev/null, making it impossible to start them. This is a stronger version of disable, since it
           prohibits all kinds of activation of the unit, including enablement and manual activation. Use this
           option with care. This honors the --runtime option to only mask temporarily until the next reboot of
           the system. The --now option may be used to ensure that the units are also stopped. This command
           expects valid unit names only, it does not accept unit file paths.

           Note that this will create a symlink under the unit's name in /etc/systemd/system/ (in case --runtime
           is not specified) or /run/systemd/system/ (in case --runtime is specified). If a matching unit file
           already exists under these directories this operation will hence fail. This means that the operation
           is primarily useful to mask units shipped by the vendor (as those are shipped in
           /usr/lib/systemd/system/ and not the aforementioned two directories), but typically doesn't work for
           units created locally (as those are typically placed precisely in the two aforementioned
           directories). Similar restrictions apply for --user mode, in which case the directories are below the
           user's home directory however.

           If a unit gets masked but its triggering units are still active, a warning containing the names of
           the triggering units is shown.  --no-warn can be used to suppress the warning.

           Added in version 238.

       unmask UNIT...
           Unmask one or more unit files, as specified on the command line. This will undo the effect of mask.
           This command expects valid unit names only, it does not accept unit file paths.

           Added in version 238.

       link PATH...
           Link a unit file that is not in the unit file search path into the unit file search path. This
           command expects an absolute path to a unit file. The effect of this may be undone with disable. The
           effect of this command is that a unit file is made available for commands such as start, even though
           it is not installed directly in the unit search path. The file system where the linked unit files are
           located must be accessible when systemd is started (e.g. anything underneath /home/ or /var/ is not
           allowed, unless those directories are located on the root file system).

           Added in version 233.

       revert UNIT...
           Revert one or more unit files to their vendor versions. This command removes drop-in configuration
           files that modify the specified units, as well as any user-configured unit file that overrides a
           matching vendor supplied unit file. Specifically, for a unit "foo.service" the matching directories
           "foo.service.d/" with all their contained files are removed, both below the persistent and runtime
           configuration directories (i.e. below /etc/systemd/system and /run/systemd/system); if the unit file
           has a vendor-supplied version (i.e. a unit file located below /usr/) any matching persistent or
           runtime unit file that overrides it is removed, too. Note that if a unit file has no vendor-supplied
           version (i.e. is only defined below /etc/systemd/system or /run/systemd/system, but not in a unit
           file stored below /usr/), then it is not removed. Also, if a unit is masked, it is unmasked.

           Effectively, this command may be used to undo all changes made with systemctl edit, systemctl
           set-property and systemctl mask and puts the original unit file with its settings back in effect.

           Added in version 230.

       add-wants TARGET UNIT..., add-requires TARGET UNIT...
           Adds "Wants=" or "Requires=" dependencies, respectively, to the specified TARGET for one or more
           units.

           This command honors --system, --user, --runtime and --global in a way similar to enable.

           Added in version 217.

       edit UNIT...
           Edit a drop-in snippet or a whole replacement file if --full is specified, to extend or override the
           specified unit.

           Depending on whether --system (the default), --user, or --global is specified, this command creates a
           drop-in file for each unit either for the system, for the calling user, or for all futures logins of
           all users. Then, the editor (see the "Environment" section below) is invoked on temporary files which
           will be written to the real location if the editor exits successfully.

           If --drop-in= is specified, the given drop-in file name will be used instead of the default
           override.conf.

           If --full is specified, this will copy the original units instead of creating drop-in files.

           If --force is specified and any units do not already exist, new unit files will be opened for
           editing.

           If --runtime is specified, the changes will be made temporarily in /run/ and they will be lost on the
           next reboot.

           If the temporary file is empty upon exit, the modification of the related unit is canceled.

           After the units have been edited, systemd configuration is reloaded (in a way that is equivalent to
           daemon-reload).

           Note that this command cannot be used to remotely edit units and that you cannot temporarily edit
           units which are in /etc/, since they take precedence over /run/.

           Added in version 218.

       get-default
           Return the default target to boot into. This returns the target unit name default.target is aliased
           (symlinked) to.

           Added in version 205.

       set-default TARGET
           Set the default target to boot into. This sets (symlinks) the default.target alias to the given
           target unit.

           Added in version 205.

   Machine Commands
       list-machines [PATTERN...]
           List the host and all running local containers with their state. If one or more PATTERNs are
           specified, only containers matching one of them are shown.

           Added in version 212.

   Job Commands
       list-jobs [PATTERN...]
           List jobs that are in progress. If one or more PATTERNs are specified, only jobs for units matching
           one of them are shown.

           When combined with --after or --before the list is augmented with information on which other job each
           job is waiting for, and which other jobs are waiting for it, see above.

           Added in version 233.

       cancel [JOB...]
           Cancel one or more jobs specified on the command line by their numeric job IDs. If no job ID is
           specified, cancel all pending jobs.

           Added in version 233.

   Environment Commands
       systemd supports an environment block that is passed to processes the manager spawns. The names of the
       variables can contain ASCII letters, digits, and the underscore character. Variable names cannot be empty
       or start with a digit. In variable values, most characters are allowed, but the whole sequence must be
       valid UTF-8. (Note that control characters like newline (NL), tab (TAB), or the escape character (ESC),
       are valid ASCII and thus valid UTF-8). The total length of the environment block is limited to
       _SC_ARG_MAX value defined by sysconf(3).

       show-environment
           Dump the systemd manager environment block. This is the environment block that is passed to all
           processes the manager spawns. The environment block will be dumped in straightforward form suitable
           for sourcing into most shells. If no special characters or whitespace is present in the variable
           values, no escaping is performed, and the assignments have the form "VARIABLE=value". If whitespace
           or characters which have special meaning to the shell are present, dollar-single-quote escaping is
           used, and assignments have the form "VARIABLE=$'value'". This syntax is known to be supported by
           bash(1), zsh(1), ksh(1), and busybox(1)'s ash(1), but not dash(1) or fish(1).

       set-environment VARIABLE=VALUE...
           Set one or more systemd manager environment variables, as specified on the command line. This command
           will fail if variable names and values do not conform to the rules listed above.

           Added in version 233.

       unset-environment VARIABLE...
           Unset one or more systemd manager environment variables. If only a variable name is specified, it
           will be removed regardless of its value. If a variable and a value are specified, the variable is
           only removed if it has the specified value.

           Added in version 233.

       import-environment VARIABLE...
           Import all, one or more environment variables set on the client into the systemd manager environment
           block. If a list of environment variable names is passed, client-side values are then imported into
           the manager's environment block. If any names are not valid environment variable names or have
           invalid values according to the rules described above, an error is raised. If no arguments are
           passed, the entire environment block inherited by the systemctl process is imported. In this mode,
           any inherited invalid environment variables are quietly ignored.

           Importing of the full inherited environment block (calling this command without any arguments) is
           deprecated. A shell will set dozens of variables which only make sense locally and are only meant for
           processes which are descendants of the shell. Such variables in the global environment block are
           confusing to other processes.

           Added in version 209.

   Manager State Commands
       daemon-reload
           Reload the systemd manager configuration. This will rerun all generators (see systemd.generator(7)),
           reload all unit files, and recreate the entire dependency tree. While the daemon is being reloaded,
           all sockets systemd listens on behalf of user configuration will stay accessible.

           This command should not be confused with the reload command.

       daemon-reexec
           Reexecute the systemd manager. This will serialize the manager state, reexecute the process and
           deserialize the state again. This command is of little use except for debugging and package upgrades.
           Sometimes, it might be helpful as a heavy-weight daemon-reload. While the daemon is being reexecuted,
           all sockets systemd listening on behalf of user configuration will stay accessible.

       log-level [LEVEL]
           If no argument is given, print the current log level of the manager. If an optional argument LEVEL is
           provided, then the command changes the current log level of the manager to LEVEL (accepts the same
           values as --log-level= described in systemd(1)).

           Added in version 244.

       log-target [TARGET]
           If no argument is given, print the current log target of the manager. If an optional argument TARGET
           is provided, then the command changes the current log target of the manager to TARGET (accepts the
           same values as --log-target=, described in systemd(1)).

           Added in version 244.

       service-watchdogs [yes|no]
           If no argument is given, print the current state of service runtime watchdogs of the manager. If an
           optional boolean argument is provided, then globally enables or disables the service runtime
           watchdogs (WatchdogSec=) and emergency actions (e.g.  OnFailure= or StartLimitAction=); see
           systemd.service(5). The hardware watchdog is not affected by this setting.

           Added in version 244.

   System Commands
       is-system-running
           Checks whether the system is operational. This returns success (exit code 0) when the system is fully
           up and running, specifically not in startup, shutdown or maintenance mode, and with no failed
           services. Failure is returned otherwise (exit code non-zero). In addition, the current state is
           printed in a short string to standard output, see the table below. Use --quiet to suppress this
           output.

           Use --wait to wait until the boot process is completed before printing the current state and
           returning the appropriate error status. If --wait is in use, states initializing or starting will not
           be reported, instead the command will block until a later state (such as running or degraded) is
           reached.

           Table 2. is-system-running output
           ┌─────────────┬──────────────────────────────┬───────────┐
           │NameDescriptionExit Code │
           ├─────────────┼──────────────────────────────┼───────────┤
           │initializing │ Early bootup, before         │ > 0       │
           │             │ basic.target is reached or   │           │
           │             │ the maintenance state        │           │
           │             │ entered.                     │           │
           ├─────────────┼──────────────────────────────┼───────────┤
           │starting     │ Late bootup, before the job  │ > 0       │
           │             │ queue becomes idle for the   │           │
           │             │ first time, or one of the    │           │
           │             │ rescue targets are reached.  │           │
           ├─────────────┼──────────────────────────────┼───────────┤
           │running      │ The system is fully          │ 0         │
           │             │ operational.                 │           │
           ├─────────────┼──────────────────────────────┼───────────┤
           │degraded     │ The system is operational    │ > 0       │
           │             │ but one or more units        │           │
           │             │ failed.                      │           │
           ├─────────────┼──────────────────────────────┼───────────┤
           │maintenance  │ The rescue or emergency      │ > 0       │
           │             │ target is active.            │           │
           ├─────────────┼──────────────────────────────┼───────────┤
           │stopping     │ The manager is shutting      │ > 0       │
           │             │ down.                        │           │
           ├─────────────┼──────────────────────────────┼───────────┤
           │offline      │ The manager is not running.  │ > 0       │
           │             │ Specifically, this is the    │           │
           │             │ operational state if an      │           │
           │             │ incompatible program is      │           │
           │             │ running as system manager    │           │
           │             │ (PID 1).                     │           │
           ├─────────────┼──────────────────────────────┼───────────┤
           │unknown      │ The operational state could  │ > 0       │
           │             │ not be determined, due to    │           │
           │             │ lack of resources or another │           │
           │             │ error cause.                 │           │
           └─────────────┴──────────────────────────────┴───────────┘
           Added in version 215.

       default
           Enter default mode. This is equivalent to systemctl isolate default.target. This operation is
           blocking by default, use --no-block to request asynchronous behavior.

       rescue
           Enter rescue mode. This is equivalent to systemctl isolate rescue.target. This operation is blocking
           by default, use --no-block to request asynchronous behavior.

       emergency
           Enter emergency mode. This is equivalent to systemctl isolate emergency.target. This operation is
           blocking by default, use --no-block to request asynchronous behavior.

       halt
           Shut down and halt the system. This is mostly equivalent to systemctl start halt.target
           --job-mode=replace-irreversibly --no-block, but also prints a wall message to all users. This command
           is asynchronous; it will return after the halt operation is enqueued, without waiting for it to
           complete. Note that this operation will simply halt the OS kernel after shutting down, leaving the
           hardware powered on. Use systemctl poweroff for powering off the system (see below).

           If combined with --force, shutdown of all running services is skipped, however all processes are
           killed and all file systems are unmounted or mounted read-only, immediately followed by the system
           halt. If --force is specified twice, the operation is immediately executed without terminating any
           processes or unmounting any file systems. This may result in data loss. Note that when --force is
           specified twice the halt operation is executed by systemctl itself, and the system manager is not
           contacted. This means the command should succeed even when the system manager has crashed.

           If combined with --when=, shutdown will be scheduled after the given timestamp. And --when=cancel
           will cancel the shutdown.

       poweroff
           Shut down and power-off the system. This is mostly equivalent to systemctl start poweroff.target
           --job-mode=replace-irreversibly --no-block, but also prints a wall message to all users. This command
           is asynchronous; it will return after the power-off operation is enqueued, without waiting for it to
           complete.

           This command honors --force and --when= in a similar way as halt.

       reboot
           Shut down and reboot the system.

           This command mostly equivalent to systemctl start reboot.target --job-mode=replace-irreversibly
           --no-block, but also prints a wall message to all users. This command is asynchronous; it will return
           after the reboot operation is enqueued, without waiting for it to complete.

           If the switch --reboot-argument= is given, it will be passed as the optional argument to the
           reboot(2) system call.

           Options --boot-loader-entry=, --boot-loader-menu=, and --firmware-setup can be used to select what to
           do after the reboot. See the descriptions of those options for details.

           This command honors --force and --when= in a similar way as halt.

           If a new kernel has been loaded via kexec --load, a kexec will be performed instead of a reboot,
           unless "SYSTEMCTL_SKIP_AUTO_KEXEC=1" has been set. If a new root file system has been set up on
           "/run/nextroot/", a soft-reboot will be performed instead of a reboot, unless
           "SYSTEMCTL_SKIP_AUTO_SOFT_REBOOT=1" has been set.

           Added in version 246.

       kexec
           Shut down and reboot the system via kexec. This command will load a kexec kernel if one wasn't loaded
           yet or fail. A kernel may be loaded earlier by a separate step, this is particularly useful if a
           custom initrd or additional kernel command line options are desired. The --force can be used to
           continue without a kexec kernel, i.e. to perform a normal reboot. The final reboot step is equivalent
           to systemctl start kexec.target --job-mode=replace-irreversibly --no-block.

           To load a kernel, an enumeration is performed following the Boot Loader Specification[1], and the
           default boot entry is loaded. For this step to succeed, the system must be using UEFI and the boot
           loader entries must be configured appropriately.  bootctl list may be used to list boot entries, see
           bootctl(1).

           This command is asynchronous; it will return after the reboot operation is enqueued, without waiting
           for it to complete.

           This command honors --force and --when= similarly to halt.

           If a new kernel has been loaded via kexec --load, a kexec will be performed when reboot is invoked,
           unless "SYSTEMCTL_SKIP_AUTO_KEXEC=1" has been set.

       soft-reboot
           Shut down and reboot userspace. This is equivalent to systemctl start soft-reboot.target
           --job-mode=replace-irreversibly --no-block. This command is asynchronous; it will return after the
           reboot operation is enqueued, without waiting for it to complete.

           This command honors --force and --when= in a similar way as halt.

           This operation only reboots userspace, leaving the kernel running. See systemd-soft-reboot.service(8)
           for details.

           If a new root file system has been set up on "/run/nextroot/", a soft-reboot will be performed when
           reboot is invoked, unless "SYSTEMCTL_SKIP_AUTO_SOFT_REBOOT=1" has been set.

           Added in version 254.

       exit [EXIT_CODE]
           Ask the service manager to quit. This is only supported for user service managers (i.e. in
           conjunction with the --user option) or in containers and is equivalent to poweroff otherwise. This
           command is asynchronous; it will return after the exit operation is enqueued, without waiting for it
           to complete.

           The service manager will exit with the specified exit code, if EXIT_CODE is passed.

           Added in version 227.

       switch-root [ROOT [INIT]]
           Switches to a different root directory and executes a new system manager process below it. This is
           intended for use in the initrd, and will transition from the initrd's system manager process (a.k.a.
           "init" process, PID 1) to the main system manager process which is loaded from the actual host root
           files system. This call takes two arguments: the directory that is to become the new root directory,
           and the path to the new system manager binary below it to execute as PID 1. If both are omitted or
           the former is an empty string it defaults to /sysroot/. If the latter is omitted or is an empty
           string, a systemd binary will automatically be searched for and used as service manager. If the
           system manager path is omitted, equal to the empty string or identical to the path to the systemd
           binary, the state of the initrd's system manager process is passed to the main system manager, which
           allows later introspection of the state of the services involved in the initrd boot phase.

           Added in version 209.

       suspend
           Suspend the system. This will trigger activation of the special target unit suspend.target. This
           command is asynchronous, and will return after the suspend operation is successfully enqueued. It
           will not wait for the suspend/resume cycle to complete.

       hibernate
           Hibernate the system. This will trigger activation of the special target unit hibernate.target. This
           command is asynchronous, and will return after the hibernation operation is successfully enqueued. It
           will not wait for the hibernate/thaw cycle to complete.

       hybrid-sleep
           Hibernate and suspend the system. This will trigger activation of the special target unit
           hybrid-sleep.target. This command is asynchronous, and will return after the hybrid sleep operation
           is successfully enqueued. It will not wait for the sleep/wake-up cycle to complete.

           Added in version 196.

       suspend-then-hibernate
           Suspend the system and hibernate it after the delay specified in systemd-sleep.conf. This will
           trigger activation of the special target unit suspend-then-hibernate.target. This command is
           asynchronous, and will return after the hybrid sleep operation is successfully enqueued. It will not
           wait for the sleep/wake-up or hibernate/thaw cycle to complete.

           Added in version 240.

   Parameter Syntax
       Unit commands listed above take either a single unit name (designated as UNIT), or multiple unit
       specifications (designated as PATTERN...). In the first case, the unit name with or without a suffix must
       be given. If the suffix is not specified (unit name is "abbreviated"), systemctl will append a suitable
       suffix, ".service" by default, and a type-specific suffix in case of commands which operate only on
       specific unit types. For example,

           # systemctl start sshd

       and

           # systemctl start sshd.service

       are equivalent, as are

           # systemctl isolate default

       and

           # systemctl isolate default.target

       Note that (absolute) paths to device nodes are automatically converted to device unit names, and other
       (absolute) paths to mount unit names.

           # systemctl status /dev/sda
           # systemctl status /home

       are equivalent to:

           # systemctl status dev-sda.device
           # systemctl status home.mount

       In the second case, shell-style globs will be matched against the primary names of all units currently in
       memory; literal unit names, with or without a suffix, will be treated as in the first case. This means
       that literal unit names always refer to exactly one unit, but globs may match zero units and this is not
       considered an error.

       Glob patterns use fnmatch(3), so normal shell-style globbing rules are used, and "*", "?", "[]" may be
       used. See glob(7) for more details. The patterns are matched against the primary names of units currently
       in memory, and patterns which do not match anything are silently skipped. For example:

           # systemctl stop sshd@*.service

       will stop all sshd@.service instances. Note that alias names of units, and units that aren't in memory
       are not considered for glob expansion.

       For unit file commands, the specified UNIT should be the name of the unit file (possibly abbreviated, see
       above), or the absolute path to the unit file:

           # systemctl enable foo.service

       or

           # systemctl link /path/to/foo.service

OPTIONS

       The following options are understood:

       -t, --type=
           The argument is a comma-separated list of unit types such as service and socket. When units are
           listed with list-units, list-dependencies, show, or status, only units of the specified types will be
           shown. By default, units of all types are shown.

           As a special case, if one of the arguments is help, a list of allowed values will be printed and the
           program will exit.

       --state=
           The argument is a comma-separated list of unit LOAD, SUB, or ACTIVE states. When listing units with
           list-units, list-dependencies, show or status, show only those in the specified states. Use
           --state=failed or --failed to show only failed units.

           As a special case, if one of the arguments is help, a list of allowed values will be printed and the
           program will exit.

           Added in version 206.

       -p, --property=
           When showing unit/job/manager properties with the show command, limit display to properties specified
           in the argument. The argument should be a comma-separated list of property names, such as "MainPID".
           Unless specified, all known properties are shown. If specified more than once, all properties with
           the specified names are shown. Shell completion is implemented for property names.

           For the manager itself, systemctl show will show all available properties, most of which are derived
           or closely match the options described in systemd-system.conf(5).

           Properties for units vary by unit type, so showing any unit (even a non-existent one) is a way to
           list properties pertaining to this type. Similarly, showing any job will list properties pertaining
           to all jobs. Properties for units are documented in systemd.unit(5), and the pages for individual
           unit types systemd.service(5), systemd.socket(5), etc.

       -P
           Equivalent to --value --property=, i.e. shows the value of the property without the property name or
           "=". Note that using -P once will also affect all properties listed with -p/--property=.

           Added in version 246.

       -a, --all
           When listing units with list-units, also show inactive units and units which are following other
           units. When showing unit/job/manager properties, show all properties regardless whether they are set
           or not.

           To list all units installed in the file system, use the list-unit-files command instead.

           When listing units with list-dependencies, recursively show dependencies of all dependent units (by
           default only dependencies of target units are shown).

           When used with status, show journal messages in full, even if they include unprintable characters or
           are very long. By default, fields with unprintable characters are abbreviated as "blob data". (Note
           that the pager may escape unprintable characters again.)

       -r, --recursive
           When listing units, also show units of local containers. Units of local containers will be prefixed
           with the container name, separated by a single colon character (":").

           Added in version 212.

       --reverse
           Show reverse dependencies between units with list-dependencies, i.e. follow dependencies of type
           WantedBy=, RequiredBy=, UpheldBy=, PartOf=, BoundBy=, instead of Wants= and similar.

           Added in version 203.

       --after
           With list-dependencies, show the units that are ordered before the specified unit. In other words,
           recursively list units following the After= dependency.

           Note that any After= dependency is automatically mirrored to create a Before= dependency. Temporal
           dependencies may be specified explicitly, but are also created implicitly for units which are
           WantedBy= targets (see systemd.target(5)), and as a result of other directives (for example
           RequiresMountsFor=). Both explicitly and implicitly introduced dependencies are shown with
           list-dependencies.

           When passed to the list-jobs command, for each printed job show which other jobs are waiting for it.
           May be combined with --before to show both the jobs waiting for each job as well as all jobs each job
           is waiting for.

           Added in version 203.

       --before
           With list-dependencies, show the units that are ordered after the specified unit. In other words,
           recursively list units following the Before= dependency.

           When passed to the list-jobs command, for each printed job show which other jobs it is waiting for.
           May be combined with --after to show both the jobs waiting for each job as well as all jobs each job
           is waiting for.

           Added in version 212.

       --with-dependencies
           When used with status, cat, list-units, and list-unit-files, those commands print all specified units
           and the dependencies of those units.

           Options --reverse, --after, --before may be used to change what types of dependencies are shown.

           Added in version 245.

       -l, --full
           Do not ellipsize unit names, process tree entries, journal output, or truncate unit descriptions in
           the output of status, list-units, list-jobs, and list-timers.

           Also, show installation targets in the output of is-enabled.

       --value
           When printing properties with show, only print the value, and skip the property name and "=". Also
           see option -P above.

           Added in version 230.

       --show-types
           When showing sockets, show the type of the socket.

           Added in version 202.

       --job-mode=
           When queuing a new job, this option controls how to deal with already queued jobs. It takes one of
           "fail", "replace", "replace-irreversibly", "isolate", "ignore-dependencies", "ignore-requirements",
           "flush", "triggering", or "restart-dependencies". Defaults to "replace", except when the isolate
           command is used which implies the "isolate" job mode.

           If "fail" is specified and a requested operation conflicts with a pending job (more specifically:
           causes an already pending start job to be reversed into a stop job or vice versa), cause the
           operation to fail.

           If "replace" (the default) is specified, any conflicting pending job will be replaced, as necessary.

           If "replace-irreversibly" is specified, operate like "replace", but also mark the new jobs as
           irreversible. This prevents future conflicting transactions from replacing these jobs (or even being
           enqueued while the irreversible jobs are still pending). Irreversible jobs can still be cancelled
           using the cancel command. This job mode should be used on any transaction which pulls in
           shutdown.target.

           "isolate" is only valid for start operations and causes all other units to be stopped when the
           specified unit is started. This mode is always used when the isolate command is used.

           "flush" will cause all queued jobs to be canceled when the new job is enqueued.

           If "ignore-dependencies" is specified, then all unit dependencies are ignored for this new job and
           the operation is executed immediately. If passed, no required units of the unit passed will be pulled
           in, and no ordering dependencies will be honored. This is mostly a debugging and rescue tool for the
           administrator and should not be used by applications.

           "ignore-requirements" is similar to "ignore-dependencies", but only causes the requirement
           dependencies to be ignored, the ordering dependencies will still be honored.

           "triggering" may only be used with systemctl stop. In this mode, the specified unit and any active
           units that trigger it are stopped. See the discussion of Triggers= in systemd.unit(5) for more
           information about triggering units.

           "restart-dependencies" may only be used with systemctl start. In this mode, dependencies of the
           specified unit will receive restart propagation, as if a restart job had been enqueued for the unit.

           Added in version 209.

       -T, --show-transaction
           When enqueuing a unit job (for example as effect of a systemctl start invocation or similar), show
           brief information about all jobs enqueued, covering both the requested job and any added because of
           unit dependencies. Note that the output will only include jobs immediately part of the transaction
           requested. It is possible that service start-up program code run as effect of the enqueued jobs might
           request further jobs to be pulled in. This means that completion of the listed jobs might ultimately
           entail more jobs than the listed ones.

           Added in version 242.

       --fail
           Shorthand for --job-mode=fail.

           When used with the kill command, if no units were killed, the operation results in an error.

           Added in version 227.

       --check-inhibitors=
           When system shutdown or sleep state is requested, this option controls checking of inhibitor locks.
           It takes one of "auto", "yes" or "no". Defaults to "auto", which will behave like "yes" for
           interactive invocations (i.e. from a TTY) and "no" for non-interactive invocations.  "yes" lets the
           request respect inhibitor locks.  "no" lets the request ignore inhibitor locks.

           Applications can establish inhibitor locks to prevent certain important operations (such as CD
           burning) from being interrupted by system shutdown or sleep. Any user may take these locks and
           privileged users may override these locks. If any locks are taken, shutdown and sleep state requests
           will normally fail (unless privileged). However, if "no" is specified or "auto" is specified on a
           non-interactive requests, the operation will be attempted. If locks are present, the operation may
           require additional privileges.

           Option --force provides another way to override inhibitors.

           Added in version 248.

       -i
           Shortcut for --check-inhibitors=no.

           Added in version 198.

       --dry-run
           Just print what would be done. Currently supported by verbs halt, poweroff, reboot, kexec, suspend,
           hibernate, hybrid-sleep, suspend-then-hibernate, default, rescue, emergency, and exit.

           Added in version 236.

       -q, --quiet
           Suppress printing of the results of various commands and also the hints about truncated log lines.
           This does not suppress output of commands for which the printed output is the only result (like
           show). Errors are always printed.

       --no-warn
           Don't generate the warnings shown by default in the following cases:

           •   when systemctl is invoked without procfs mounted on /proc/,

           •   when using enable or disable on units without install information (i.e. don't have or have an
               empty [Install] section),

           •   when using disable combined with --user on units that are enabled in global scope,

           •   when a stop-ped, disable-d, or mask-ed unit still has active triggering units.

           Added in version 253.

       --no-block
           Do not synchronously wait for the requested operation to finish. If this is not specified, the job
           will be verified, enqueued and systemctl will wait until the unit's start-up is completed. By passing
           this argument, it is only verified and enqueued. This option may not be combined with --wait.

       --wait
           Synchronously wait for started units to terminate again. This option may not be combined with
           --no-block. Note that this will wait forever if any given unit never terminates (by itself or by
           getting stopped explicitly); particularly services which use "RemainAfterExit=yes".

           When used with is-system-running, wait until the boot process is completed before returning.

           Added in version 232.

       --user
           Talk to the service manager of the calling user, rather than the service manager of the system.

       --system
           Talk to the service manager of the system. This is the implied default.

       --failed
           List units in failed state. This is equivalent to --state=failed.

           Added in version 233.

       --no-wall
           Do not send wall message before halt, power-off and reboot.

       --global
           When used with enable and disable, operate on the global user configuration directory, thus enabling
           or disabling a unit file globally for all future logins of all users.

       --no-reload
           When used with enable and disable, do not implicitly reload daemon configuration after executing the
           changes.

       --no-ask-password
           When used with start and related commands, disables asking for passwords. Background services may
           require input of a password or passphrase string, for example to unlock system hard disks or
           cryptographic certificates. Unless this option is specified and the command is invoked from a
           terminal, systemctl will query the user on the terminal for the necessary secrets. Use this option to
           switch this behavior off. In this case, the password must be supplied by some other means (for
           example graphical password agents) or the service might fail. This also disables querying the user
           for authentication for privileged operations.

       --kill-whom=
           When used with kill, choose which processes to send a UNIX process signal to. Must be one of main,
           control or all to select whether to kill only the main process, the control process or all processes
           of the unit. The main process of the unit is the one that defines the life-time of it. A control
           process of a unit is one that is invoked by the manager to induce state changes of it. For example,
           all processes started due to the ExecStartPre=, ExecStop= or ExecReload= settings of service units
           are control processes. Note that there is only one control process per unit at a time, as only one
           state change is executed at a time. For services of type Type=forking, the initial process started by
           the manager for ExecStart= is a control process, while the process ultimately forked off by that one
           is then considered the main process of the unit (if it can be determined). This is different for
           service units of other types, where the process forked off by the manager for ExecStart= is always
           the main process itself. A service unit consists of zero or one main process, zero or one control
           process plus any number of additional processes. Not all unit types manage processes of these types
           however. For example, for mount units, control processes are defined (which are the invocations of
           /usr/bin/mount and /usr/bin/umount), but no main process is defined. If omitted, defaults to all.

           Added in version 252.

       --kill-value=INT
           If used with the kill command, enqueues a signal along with the specified integer value parameter to
           the specified process(es). This operation is only available for POSIX Realtime Signals (i.e.
           --signal=SIGRTMIN+...  or --signal=SIGRTMAX-...), and ensures the signals are generated via the
           sigqueue(3) system call, rather than kill(3). The specified value must be a 32-bit signed integer,
           and may be specified either in decimal, in hexadecimal (if prefixed with "0x"), octal (if prefixed
           with "0o") or binary (if prefixed with "0b")

           If this option is used the signal will only be enqueued on the control or main process of the unit,
           never on other processes belonging to the unit, i.e.  --kill-whom=all will only affect main and
           control processes but no other processes.

           Added in version 254.

       -s, --signal=
           When used with kill, choose which signal to send to selected processes. Must be one of the well-known
           signal specifiers such as SIGTERM, SIGINT or SIGSTOP. If omitted, defaults to SIGTERM.

           The special value "help" will list the known values and the program will exit immediately, and the
           special value "list" will list known values along with the numerical signal numbers and the program
           will exit immediately.

       --what=
           Select what type of per-unit resources to remove when the clean command is invoked, see above. Takes
           one of configuration, state, cache, logs, runtime, fdstore to select the type of resource. This
           option may be specified more than once, in which case all specified resource types are removed. Also
           accepts the special value all as a shortcut for specifying all six resource types. If this option is
           not specified defaults to the combination of cache, runtime and fdstore, i.e. the three kinds of
           resources that are generally considered to be redundant and can be reconstructed on next invocation.
           Note that the explicit removal of the fdstore resource type is only useful if the
           FileDescriptorStorePreserve= option is enabled, since the file descriptor store is otherwise cleaned
           automatically when the unit is stopped.

           Added in version 243.

       -f, --force
           When used with enable, overwrite any existing conflicting symlinks.

           When used with edit, create all of the specified units which do not already exist.

           When used with halt, poweroff, reboot or kexec, execute the selected operation without shutting down
           all units. However, all processes will be killed forcibly and all file systems are unmounted or
           remounted read-only. This is hence a drastic but relatively safe option to request an immediate
           reboot. If --force is specified twice for these operations (with the exception of kexec), they will
           be executed immediately, without terminating any processes or unmounting any file systems. Warning:
           specifying --force twice with any of these operations might result in data loss. Note that when
           --force is specified twice the selected operation is executed by systemctl itself, and the system
           manager is not contacted. This means the command should succeed even when the system manager has
           crashed.

       --message=
           When used with halt, poweroff or reboot, set a short message explaining the reason for the operation.
           The message will be logged together with the default shutdown message.

           Added in version 225.

       --now
           When used with enable, the units will also be started. When used with disable or mask, the units will
           also be stopped. The start or stop operation is only carried out when the respective enable or
           disable operation has been successful.

           Added in version 220.

       --root=
           When used with enable/disable/is-enabled (and related commands), use the specified root path when
           looking for unit files. If this option is present, systemctl will operate on the file system
           directly, instead of communicating with the systemd daemon to carry out changes.

       --image=image
           Takes a path to a disk image file or block device node. If specified, all operations are applied to
           file system in the indicated disk image. This option is similar to --root=, but operates on file
           systems stored in disk images or block devices. The disk image should either contain just a file
           system or a set of file systems within a GPT partition table, following the Discoverable Partitions
           Specification[2]. For further information on supported disk images, see systemd-nspawn(1)'s switch of
           the same name.

           Added in version 252.

       --image-policy=policy
           Takes an image policy string as argument, as per systemd.image-policy(7). The policy is enforced when
           operating on the disk image specified via --image=, see above. If not specified defaults to the "*"
           policy, i.e. all recognized file systems in the image are used.

       --runtime
           When used with enable, disable, edit, (and related commands), make changes only temporarily, so that
           they are lost on the next reboot. This will have the effect that changes are not made in
           subdirectories of /etc/ but in /run/, with identical immediate effects, however, since the latter is
           lost on reboot, the changes are lost too.

           Similarly, when used with set-property, make changes only temporarily, so that they are lost on the
           next reboot.

       --preset-mode=
           Takes one of "full" (the default), "enable-only", "disable-only". When used with the preset or
           preset-all commands, controls whether units shall be disabled and enabled according to the preset
           rules, or only enabled, or only disabled.

           Added in version 215.

       -n, --lines=
           When used with status, controls the number of journal lines to show, counting from the most recent
           ones. Takes a positive integer argument, or 0 to disable journal output. Defaults to 10.

       -o, --output=
           When used with status, controls the formatting of the journal entries that are shown. For the
           available choices, see journalctl(1). Defaults to "short".

       --firmware-setup
           When used with the reboot, poweroff, or halt command, indicate to the system's firmware to reboot
           into the firmware setup interface for the next boot. Note that this functionality is not available on
           all systems.

           Added in version 220.

       --boot-loader-menu=timeout
           When used with the reboot, poweroff, or halt command, indicate to the system's boot loader to show
           the boot loader menu on the following boot. Takes a time value as parameter — indicating the menu
           timeout. Pass zero in order to disable the menu timeout. Note that not all boot loaders support this
           functionality.

           Added in version 242.

       --boot-loader-entry=ID
           When used with the reboot, poweroff, or halt command, indicate to the system's boot loader to boot
           into a specific boot loader entry on the following boot. Takes a boot loader entry identifier as
           argument, or "help" in order to list available entries. Note that not all boot loaders support this
           functionality.

           Added in version 242.

       --reboot-argument=
           This switch is used with reboot. The value is architecture and firmware specific. As an example,
           "recovery" might be used to trigger system recovery, and "fota" might be used to trigger a “firmware
           over the air” update.

           Added in version 246.

       --plain
           When used with list-dependencies, list-units or list-machines, the output is printed as a list
           instead of a tree, and the bullet circles are omitted.

           Added in version 203.

       --timestamp=
           Change the format of printed timestamps. The following values may be used:

           pretty (this is the default)
               "Day YYYY-MM-DD HH:MM:SS TZ"

               Added in version 248.

           unix
               "@seconds-since-the-epoch"

               Added in version 251.

           us, μs
               "Day YYYY-MM-DD HH:MM:SS.UUUUUU TZ"

               Added in version 248.

           utc
               "Day YYYY-MM-DD HH:MM:SS UTC"

               Added in version 248.

           us+utc, μs+utc
               "Day YYYY-MM-DD HH:MM:SS.UUUUUU UTC"

               Added in version 248.

           Added in version 247.

       --mkdir
           When used with bind, creates the destination file or directory before applying the bind mount. Note
           that even though the name of this option suggests that it is suitable only for directories, this
           option also creates the destination file node to mount over if the object to mount is not a
           directory, but a regular file, device node, socket or FIFO.

           Added in version 248.

       --marked
           Only allowed with reload-or-restart. Enqueues restart jobs for all units that have the
           "needs-restart" mark, and reload jobs for units that have the "needs-reload" mark. When a unit marked
           for reload does not support reload, restart will be queued. Those properties can be set using
           set-property Markers=....

           Unless --no-block is used, systemctl will wait for the queued jobs to finish.

           Added in version 248.

       --read-only
           When used with bind, creates a read-only bind mount.

           Added in version 248.

       --drop-in=NAME
           When used with edit, use NAME as the drop-in file name instead of override.conf.

           Added in version 253.

       --when=
           When used with halt, poweroff, reboot or kexec, schedule the action to be performed at the given
           timestamp, which should adhere to the syntax documented in systemd.time(7) section "PARSING
           TIMESTAMPS". Specially, if "show" is given, the currently scheduled action will be shown, which can
           be canceled by passing an empty string or "cancel".

           Added in version 254.

       -H, --host=
           Execute the operation remotely. Specify a hostname, or a username and hostname separated by "@", to
           connect to. The hostname may optionally be suffixed by a port ssh is listening on, separated by ":",
           and then a container name, separated by "/", which connects directly to a specific container on the
           specified host. This will use SSH to talk to the remote machine manager instance. Container names may
           be enumerated with machinectl -H HOST. Put IPv6 addresses in brackets.

       -M, --machine=
           Execute operation on a local container. Specify a container name to connect to, optionally prefixed
           by a user name to connect as and a separating "@" character. If the special string ".host" is used in
           place of the container name, a connection to the local system is made (which is useful to connect to
           a specific user's user bus: "--user --machine=lennart@.host"). If the "@" syntax is not used, the
           connection is made as root user. If the "@" syntax is used either the left hand side or the right
           hand side may be omitted (but not both) in which case the local user name and ".host" are implied.

       --no-pager
           Do not pipe output into a pager.

       --legend=BOOL
           Enable or disable printing of the legend, i.e. column headers and the footer with hints. The legend
           is printed by default, unless disabled with --quiet or similar.

       -h, --help
           Print a short help text and exit.

       --version
           Print a short version string and exit.

EXIT STATUS

       On success, 0 is returned, a non-zero failure code otherwise.

       systemctl uses the return codes defined by LSB, as defined in LSB 3.0.0[3].

       Table 3. LSB return codes
       ┌──────┬─────────────────────────────┬──────────────────────────┐
       │ValueDescription in LSBUse in systemd           │
       ├──────┼─────────────────────────────┼──────────────────────────┤
       │0     │ "program is running or      │ unit is active           │
       │      │ service is OK"              │                          │
       ├──────┼─────────────────────────────┼──────────────────────────┤
       │1     │ "program is dead and        │ unit not failed (used by │
       │      │ /var/run pid file exists"   │ is-failed)               │
       ├──────┼─────────────────────────────┼──────────────────────────┤
       │2     │ "program is dead and        │ unused                   │
       │      │ /var/lock lock file exists" │                          │
       ├──────┼─────────────────────────────┼──────────────────────────┤
       │3     │ "program is not running"    │ unit is not active       │
       ├──────┼─────────────────────────────┼──────────────────────────┤
       │4     │ "program or service status  │ no such unit             │
       │      │ is unknown"                 │                          │
       └──────┴─────────────────────────────┴──────────────────────────┘

       The mapping of LSB service states to systemd unit states is imperfect, so it is better to not rely on
       those return values but to look for specific unit states and substates instead.

ENVIRONMENT

       $SYSTEMD_EDITOR
           Editor to use when editing units; overrides $EDITOR and $VISUAL. If neither $SYSTEMD_EDITOR nor
           $EDITOR nor $VISUAL are present or if it is set to an empty string or if their execution failed,
           systemctl will try to execute well known editors in this order: editor(1), nano(1), vim(1), vi(1).

           Added in version 218.

       $SYSTEMD_LOG_LEVEL
           The maximum log level of emitted messages (messages with a higher log level, i.e. less important
           ones, will be suppressed). Either one of (in order of decreasing importance) emerg, alert, crit, err,
           warning, notice, info, debug, or an integer in the range 0...7. See syslog(3) for more information.

       $SYSTEMD_LOG_COLOR
           A boolean. If true, messages written to the tty will be colored according to priority.

           This setting is only useful when messages are written directly to the terminal, because journalctl(1)
           and other tools that display logs will color messages based on the log level on their own.

       $SYSTEMD_LOG_TIME
           A boolean. If true, console log messages will be prefixed with a timestamp.

           This setting is only useful when messages are written directly to the terminal or a file, because
           journalctl(1) and other tools that display logs will attach timestamps based on the entry metadata on
           their own.

       $SYSTEMD_LOG_LOCATION
           A boolean. If true, messages will be prefixed with a filename and line number in the source code
           where the message originates.

           Note that the log location is often attached as metadata to journal entries anyway. Including it
           directly in the message text can nevertheless be convenient when debugging programs.

       $SYSTEMD_LOG_TARGET
           The destination for log messages. One of console (log to the attached tty), console-prefixed (log to
           the attached tty but with prefixes encoding the log level and "facility", see syslog(3), kmsg (log to
           the kernel circular log buffer), journal (log to the journal), journal-or-kmsg (log to the journal if
           available, and to kmsg otherwise), auto (determine the appropriate log target automatically, the
           default), null (disable log output).

       $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, including less(1) and more(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.

           Note: if $SYSTEMD_PAGERSECURE is not set, $SYSTEMD_PAGER (as well as $PAGER) will be silently
           ignored.

       $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.

           See less(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_PAGERSECURE
           Takes a boolean argument. When true, the "secure" mode of the pager is enabled; if false, disabled.
           If $SYSTEMD_PAGERSECURE is not set at all, secure mode is enabled if the effective UID is not the
           same as the owner of the login session, see geteuid(2) and sd_pid_get_owner_uid(3). In secure mode,
           LESSSECURE=1 will be set when invoking the pager, and the pager shall disable commands that open or
           create new files or start new subprocesses. When $SYSTEMD_PAGERSECURE is not set at all, pagers which
           are not known to implement secure mode will not be used. (Currently only less(1) implements secure
           mode.)

           Note: when commands are invoked with elevated privileges, for example under sudo(8) or pkexec(1),
           care must be taken to ensure that unintended interactive features are not enabled. "Secure" mode for
           the pager may be enabled automatically as describe above. Setting SYSTEMD_PAGERSECURE=0 or not
           removing it from the inherited environment allows the user to invoke arbitrary commands. Note that if
           the $SYSTEMD_PAGER or $PAGER variables are to be honoured, $SYSTEMD_PAGERSECURE must be set too. It
           might be reasonable to completely disable the pager using --no-pager instead.

       $SYSTEMD_COLORS
           Takes a boolean argument. When true, systemd and related utilities will use colors in their output,
           otherwise the output will be monochrome. Additionally, the variable can take one of the following
           special values: "16", "256" to restrict the use of colors to the base 16 or 256 ANSI colors,
           respectively. This can be specified to override the automatic decision 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.

SEE ALSO

       systemd(1), journalctl(1), loginctl(1), machinectl(1), systemd.unit(5), systemd.resource-control(5),
       systemd.special(7), wall(1), systemd.preset(5), systemd.generator(7), glob(7)

NOTES

        1. Boot Loader Specification
           https://uapi-group.org/specifications/specs/boot_loader_specification

        2. Discoverable Partitions Specification
           https://uapi-group.org/specifications/specs/discoverable_partitions_specification

        3. LSB 3.0.0
           http://refspecs.linuxbase.org/LSB_3.0.0/LSB-PDA/LSB-PDA/iniscrptact.html