OPTIONS¶
The following options are understood:
-t, --type=
The argument should be a comma-separated list of unit
  types such as 
service and 
socket.
If one of the arguments is a unit type, when listing units, limit
    display to certain unit types. Otherwise, units of all types will be
  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 should be a comma-separated list of unit
  LOAD, SUB, or ACTIVE states. When listing units, show only those in specified
  states. Use --state=failed to show only failed units.
-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. Those properties are documented 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.
 
-a, --all
When listing units, show all loaded units, regardless of
  their state, including inactive units. When showing unit/job/manager
  properties, show all properties regardless whether they are set or not.
To list all units installed on the system, use the
    list-unit-files command instead.
 
-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 (":").
--reverse
Show reverse dependencies between units with
  list-dependencies, i.e. follow dependencies of type WantedBy=,
  RequiredBy=, RequiredByOverrridable=, PartOf=,
  BoundBy=, instead of Wants= and similar.
--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.
 
--before
With list-dependencies, show the units that are
  ordered after the specified unit. In other words, recursively list units
  following the Before= dependency.
-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.
 
--show-types
When showing sockets, show the type of the socket.
--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" or
  "flush". 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.
"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
    honoured.
 
-i, --ignore-inhibitors
When system shutdown or a sleep state is requested,
  ignore inhibitor locks. Applications can establish inhibitor locks to avoid
  that certain important operations (such as CD burning or suchlike) are
  interrupted by system shutdown or a sleep state. 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 (regardless of whether
  privileged or not) and a list of active locks is printed. However, if
  --ignore-inhibitors is specified, the locks are ignored and not
  printed, and the operation attempted anyway, possibly requiring additional
  privileges.
-q, --quiet
Suppress output to standard output in snapshot,
  is-active, is-failed, is-enabled,
  is-system-running, enable and disable.
--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 it is completed. By passing this argument, it
  is only verified and enqueued.
--system
Talk to the service manager of the system. This is the
  implied default.
--no-wall
Do not send wall message before halt, power-off,
  reboot.
--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-who=
When used with kill, choose which processes to
  send a 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.
-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.
-f, --force
When used with 
enable, overwrite any existing
  conflicting symlinks.
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, 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.
 
--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.
--root=
When used with
  enable/disable/is-enabled (and related commands), use
  alternative root path when looking for unit files.
--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.
-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. 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".
 
--plain
When used with list-dependencies, the output is
  printed as a list instead of a tree.
-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 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.
-M, --machine=
Execute operation on a local container. Specify a
  container name to connect to.
--no-pager
Do not pipe output into a pager.
--no-legend
Do not print the legend, i.e. column headers and the
  footer with hints.
-h, --help
Print a short help text and exit.
--version
Print a short version string and exit.
COMMANDS¶
The following commands are understood:
Unit Commands¶
list-units [PATTERN...]
List known units (subject to limitations specified with
  
-t). If one or more 
PATTERNs are specified, only units matching
  one of them are shown.
This is the default command.
 
list-sockets [PATTERN...]
List socket units 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.
See also the options --show-types, --all, and
    --state=.
 
list-timers [PATTERN...]
List timer units ordered by the time they elapse next. If
  one or more 
PATTERNs are specified, only units matching one of them are
  shown.
See also the options --all and --state=.
 
start PATTERN...
Start (activate) one or more units specified on the
  command line.
Note that glob patterns operate on a list of currently loaded
    units. Units which are not active and are not in a failed state usually are
    not loaded, and would 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.
 
stop PATTERN...
Stop (deactivate) one or more units specified on the
  command line.
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...
Restart one or more units specified on the command line.
  If the units are not running yet, they will be started.
try-restart PATTERN...
Restart one or more units specified on the command line
  if the units are running. This does nothing if units are not running. Note
  that, for compatibility with Red Hat init scripts, condrestart is
  equivalent to this command.
reload-or-restart PATTERN...
Reload one or more units if they support it. If not,
  restart them instead. If the units are not running yet, they will be
  started.
reload-or-try-restart PATTERN...
Reload one or more units if they support it. If not,
  restart them instead. This does nothing if the units are not running. Note
  that, for compatibility with SysV init scripts, force-reload is
  equivalent to this command.
isolate NAME
Start the unit specified on the command line and its
  dependencies and stop all others. If a unit name with no extension is given,
  an extension of ".target" will be assumed.
This is similar to changing the runlevel in a traditional init
    system. The isolate command will immediately stop processes that are
    not enabled in the new unit, possibly including the graphical environment or
    terminal you are currently using.
Note that this is allowed only on units where AllowIsolate=
    is enabled. See systemd.unit(5) for details.
 
kill PATTERN...
Send a signal to one or more processes of the unit. Use
  --kill-who= to select which process to kill. Use --signal= to
  select the signal to send.
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 are in a
  "failed" state. 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 state to standard output.
status [PATTERN...|PID...]]
Show terse runtime status information about one or more
  units, followed by most recent log data from the journal. If no units are
  specified, show system status. If combined with 
--all, also show the
  status of all units (subject to limitations specified with 
-t). If a
  PID is passed, show information about the unit the process belongs to.
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 changes with --lines and
    --full, see above. In addition, journalctl
    --unit=NAME use a similar filter for messages and might be
    more convenient.
 
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 is shown, and if a
  job id is specified, properties of the job is 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.
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.
set-property NAME
    ASSIGNMENT...
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 instantly,
  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
    CPUShares=777
Note that this command allows changing multiple properties at the
    same time, which is preferable over setting them individually. Like unit
    file configuration settings, assigning the empty list to list parameters
    will reset the list.
 
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.
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 restarted or reset with this command.
list-dependencies [NAME]
Shows units required and wanted by the specified unit.
  This recursively lists units following the 
Requires=,
  
RequiresOverridable=, 
Requisite=, 
RequisiteOverridable=,
  
Wants=, 
BindsTo= dependencies. If no unit is specified,
  default.target 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.
 
Unit File Commands¶
list-unit-files [PATTERN...]
List installed unit files and their enablement state (as
  reported by is-enabled). If one or more PATTERNs are specified,
  only units whose filename (just the last component of the path) matches one of
  them are shown.
enable NAME...
Enable one or more unit files or unit file instances, as
  specified on the command line. This will create a number of symlinks as
  encoded in the "[Install]" sections of the unit files. After the
  symlinks have been created, the systemd configuration is reloaded (in a way
  that is equivalent to 
daemon-reload) 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, either
  
--now should be used together with this command, or an additional
  
start command must be invoked for the unit. Also note that in case of
  instance enablement, symlinks named the same as instances are created in the
  install location, however they all point to the same template unit file.
This command will print the actions executed. This output may be
    suppressed by passing --quiet.
Note that this operation creates only the suggested symlinks for
    the units. 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 in the 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 to ensure the changes are
    taken into account.
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.
If --runtime is specified, then this enables the unit only
    this boot.
Using enable on masked units results in an error.
 
disable NAME...
Disables one or more units. This removes all symlinks to
  the specified unit files from the unit configuration directory, and hence
  undoes the changes made by 
enable. Note however that this removes all
  symlinks to the unit files (i.e. including manual additions), not just those
  actually created by 
enable. This call implicitly reloads the systemd
  daemon configuration after completing the disabling of the units. Note that
  this command does not implicitly stop the units that are being disabled. If
  this is desired, either 
--now should be used together with this
  command, or an additional 
stop command should be executed afterwards.
This command will print the actions executed. This output may be
    suppressed by passing --quiet.
This command honors --runtime in a similar way as
    enable.
 
reenable NAME...
Reenable one or more unit files, as specified on the
  command line. This is a combination of disable and enable and is
  useful to reset the symlinks a unit is enabled with to the defaults configured
  in the "[Install]" section of the unit file.
preset NAME...
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.
For more information on the preset policy format, see
    systemd.preset(5). For more information on the concept of presets,
    please consult the Preset[1] document.
 
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.
 
is-enabled NAME...
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
  
    | Printed string | 
    Meaning | 
    Return value | 
  
  
    | "enabled" | 
    Enabled through a symlink in .wants directory (permanently
      or just in /run). | 
    0 | 
  
  
    | "enabled-runtime" | 
  
  
    | "linked" | 
    Made available through a symlink to the unit file
      (permanently or just in /run). | 
    1 | 
  
  
    | "linked-runtime" | 
  
  
    | "masked" | 
    Disabled entirely (permanently or just in /run). | 
    1 | 
  
  
    | "masked-runtime" | 
  
  
    | "static" | 
    Unit file is not enabled, and has no provisions for enabling in the
      "[Install]" section. | 
    0 | 
  
  
    | "indirect" | 
    Unit file itself is not enabled, but it has a non-empty Also=
      setting in the "[Install]" section, listing other unit files
      that might be enabled. | 
    0 | 
  
  
    | "disabled" | 
    Unit file is not enabled. | 
    1 | 
  
  
    | "bad" | 
    Unit file is invalid or another error occured. Note that
      is-enabled wil not actually return this state, but print an error
      message instead. However the unit file listing printed by
      list-unit-files might show it. | 
    > 0 | 
  
 
mask NAME...
  
Mask one or more unit files, as specified on the command
  line. This will link these units 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
  can be used to ensure that the units are also stopped.
unmask NAME...
Unmask one or more unit files, as specified on the
  command line. This will undo the effect of mask.
link FILENAME...
Link a unit file that is not in the unit file search
  paths into the unit file search path. This requires an absolute path to a unit
  file. The effect of this can be undone with disable. The effect of this
  command is that a unit file is available for start and other commands
  although it is not installed directly in the unit search path.
add-wants TARGET
    NAME..., add-requires
    TARGET NAME...
Adds "Wants=" resp. "Requires="
  dependency to the specified 
TARGET for one or more units.
This command honors --runtime in a similar way as
    enable.
 
edit NAME...
Edit a drop-in snippet or a whole replacement file if
  
--full is specified, to extend or override the specified unit.
This creates a drop-in file for a unit. 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 --full is specified, this will copy the original units
    instead of creating drop-in files.
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.
 
get-default
Return the default target to boot into. This returns the
  target unit name default.target is aliased (symlinked) to.
set-default NAME
Set the default target to boot into. This sets (symlinks)
  the default.target alias to the given target unit.
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.
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.
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.
Snapshot Commands¶
snapshot [NAME]
Create a snapshot. If a snapshot name is specified, the
  new snapshot will be named after it. If none is specified, an automatic
  snapshot name is generated. In either case, the snapshot name used is printed
  to standard output, unless 
--quiet is specified.
A snapshot refers to a saved state of the systemd manager. It is
    implemented itself as a unit that is generated dynamically with this command
    and has dependencies on all units active at the time. At a later time, the
    user may return to this state by using the isolate command on the
    snapshot unit.
Snapshots are only useful for saving and restoring which units are
    running or are stopped, they do not save/restore any other state. Snapshots
    are dynamic and lost on reboot.
 
delete PATTERN...
Remove a snapshot previously created with
  snapshot.
Environment Commands¶
show-environment
Dump the systemd manager environment block. The
  environment block will be dumped in straight-forward form suitable for
  sourcing into a shell script. This environment block will be passed to all
  processes the manager spawns.
set-environment VARIABLE=VALUE...
Set one or more systemd manager environment variables, as
  specified on the command line.
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.
import-environment [VARIABLE...]
Import all, one or more environment variables set on the
  client into the systemd manager environment block. If no arguments are passed,
  the entire environment block is imported. Otherwise, a list of one or more
  environment variable names should be passed, whose client-side values are then
  imported into the manager's environment block.
Manager Lifecycle Commands¶
daemon-reload
Reload 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.
System Commands¶
is-system-running
Checks whether the system is operational. This returns
  success when the system is fully up and running, meaning not in startup,
  shutdown or maintenance mode. Failure is returned otherwise. In addition, the
  current state is printed in a short string to standard output, see table
  below. Use 
--quiet to suppress this output.
Table 2. Manager Operational States
  
    | Name | 
    Description | 
  
  
    | initializing | 
    Early bootup, before basic.target is reached or the maintenance
      state entered. | 
  
  
    | starting | 
    Late bootup, before the job queue becomes idle for the first time, or
      one of the rescue targets are reached. | 
  
  
    | running | 
    The system is fully operational. | 
  
  
    | degraded | 
    The system is operational but one or more units failed. | 
  
  
    | maintenance | 
    The rescue or emergency target is active. | 
  
  
    | stopping | 
    The manager is shutting down. | 
  
 
default
  
Enter default mode. This is mostly equivalent to
  isolate default.target.
rescue
Enter rescue mode. This is mostly equivalent to
  isolate rescue.target, but also prints a wall message to all
  users.
emergency
Enter emergency mode. This is mostly equivalent to
  isolate emergency.target, but also prints a wall message to all
  users.
halt
Shut down and halt the system. This is mostly equivalent
  to start halt.target --irreversible, but also prints a wall message to
  all users. 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.
poweroff
Shut down and power-off the system. This is mostly
  equivalent to start poweroff.target --irreversible, but also prints a
  wall message to all users. 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
  powering off. 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.
reboot [arg]
Shut down and reboot the system. This is mostly
  equivalent to 
start reboot.target --irreversible, but also prints a
  wall message to all users. 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
  reboot. 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.
If the optional argument arg is given, it will be passed as
    the optional argument to the reboot(2) system call. 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.
 
kexec
Shut down and reboot the system via kexec. This is mostly
  equivalent to start kexec.target --irreversible, but also prints a wall
  message to all users. 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 reboot.
switch-root ROOT
  [INIT]
Switches to a different root directory and executes a new
  system manager process below it. This is intended for usage in initial RAM
  disks ("initrd"), and will transition from the initrd's system
  manager process (a.k.a "init" process) to the main system manager
  process. 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 the latter is omitted or the empty string, a systemd
  binary will automatically be searched for and used as init. If the system
  manager path is omitted or equal to the empty string, 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.
suspend
Suspend the system. This will trigger activation of the
  special suspend.target target.
hibernate
Hibernate the system. This will trigger activation of the
  special hibernate.target target.
hybrid-sleep
Hibernate and suspend the system. This will trigger
  activation of the special hybrid-sleep.target target.
Parameter Syntax¶
Unit commands listed above take either a single unit name
    (designated as NAME), 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, 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,
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
    currently loaded units; 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 names of currently loaded units, and patterns which do not match
    anything are silently skipped. For example:
# systemctl stop sshd@*.service
 
will stop all sshd@.service instances.
For unit file commands, the specified NAME should be the
    full name of the unit file, or the absolute path to the unit file:
# systemctl enable foo.service
 
or
# systemctl link /path/to/foo.service