systemctl(1)


NAME

   systemctl - Control the systemd system and service manager

SYNOPSIS

   systemctl [OPTIONS...] COMMAND [NAME...]

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.

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 the specified
       states. Use --state=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.

   -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 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).

   -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=, 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.

   --value
       When printing properties with show, only print the value, and skip
       the property name and "=".

   --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 honored.

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

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

   -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 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-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".

   --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.

   --no-wall
       Do not send wall message before halt, power-off, 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-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 /bin/mount and /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 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 hangs or crashed.

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

   --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 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.

   --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".

   --firmware-setup
       When used with the reboot command, indicate to the system's
       firmware to boot into setup mode. Note that this is currently only
       supported on some EFI systems and only if the system was booted in
       EFI mode.

   --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.

   -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 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.

       This is the default command.

   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=.

   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.

       Also see --all and --state=.

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

       Note that glob patterns operate on the set of primary 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.

   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.

   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.

   try-reload-or-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.

   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 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.

   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.

   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.

   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

       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. 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=, Requisite=,
       ConsistsOf=, 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 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).

   enable NAME..., 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.

       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.

       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, or only this boot. 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 NAME...
       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.

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

   reenable NAME...
       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.

   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.  NAME must be the real unit name, any
       alias names are ignored silently.

       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
       
       Name               Description              Exit Code 
       
       "enabled"          Enabled via                        
        .wants/, .requires/                
       "enabled-runtime"  or alias symlinks                  
                          (permanently in          0         
                          /etc/systemd/system/,              
                          or transiently in                  
                          /run/systemd/system/).             
       
       "linked"           Made available through             
        one or more symlinks               
       "linked-runtime"   to the unit 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.                  
       
       "masked"           Completely disabled,               
        so that any start                  
       "masked-runtime"   operation on it 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  0         
                          not enabled, but it has            
                          a non-empty Also=                  
                          setting in the                     
                          "[Install]" unit file              
                          section, listing other             
                          unit files that might              
                          be enabled.                        
       
       "disabled"         The unit file is not     > 0       
                          enabled, but contains              
                          an "[Install]" section             
                          with installation                  
                          instructions.                      
       
       "generated"        The unit file was        0         
                          generated 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         > 0       
                          invalid or 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.                           
       

   mask NAME...
       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.

   unmask NAME...
       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.

   link PATH...
       Link a unit file that is not in the unit file search paths 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.

   revert NAME...
       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.

   add-wants TARGET NAME..., add-requires TARGET NAME...
       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.

   edit NAME...
       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 --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.

   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.

   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 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.

   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.

       Table 2. is-system-running output
       
       Name          Description          Exit Code 
       
       initializing  Early bootup,        > 0       
                     before basic.target            
                     is reached or the              
                     maintenance state              
                     entered.                       
       
       starting      Late bootup, before  > 0       
                     the job 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        > 0       
                     operational but one            
                     or more units                  
                     failed.                        
       
       maintenance   The rescue or        > 0       
                     emergency target is            
                     active.                        
       
       stopping      The manager is       > 0       
                     shutting down.                 
       
       offline       The manager is not   > 0       
                     running.                       
                     Specifically, this             
                     is the operational             
                     state if an                    
                     incompatible                   
                     program is running             
                     as system manager              
                     (PID 1).                       
       
       unknown       The operational      > 0       
                     state could not be             
                     determined, due to             
                     lack of resources              
                     or another error               
                     cause.                         
       

   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 --job-mode=replace-irreversibly, 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. 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 hangs
       or crashed.

   poweroff
       Shut down and power-off the system. This is mostly equivalent to
       start poweroff.target --job-mode=replace-irreversibly, 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. Note that when --force is specified twice the power-off
       operation is executed by systemctl itself, and the system manager
       is not contacted. This means the command should succeed even when
       the system manager hangs or crashed.

   reboot [arg]
       Shut down and reboot the system. This is mostly equivalent to start
       reboot.target --job-mode=replace-irreversibly, 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. Note that when --force is specified twice the reboot
       operation is executed by systemctl itself, and the system manager
       is not contacted. This means the command should succeed even when
       the system manager hangs or crashed.

       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 --job-mode=replace-irreversibly,
       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.

   exit [EXIT_CODE]
       Ask the systemd 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.

       The systemd manager can exit with a non-zero exit code if the
       optional argument EXIT_CODE is given.

   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 which is loaded from the actual host volume. 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, 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.

   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 (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 NAME 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

EXIT STATUS

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

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).

   $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.

   $SYSTEMD_LESS
       Override the options passed to less (by default "FRSXMK").

   $SYSTEMD_LESSCHARSET
       Override the charset passed to less (by default "utf-8", if the
       invoking terminal is determined to be UTF-8 compatible).

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. Preset
       http://freedesktop.org/wiki/Software/systemd/Preset





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