SYSTEMD.UNIT(5)                  systemd.unit                  SYSTEMD.UNIT(5)

       systemd.unit - Unit configuration

       service.service, socket.socket, device.device, mount.mount,
       automount.automount, swap.swap,, path.path, timer.timer,
       slice.slice, scope.scope

   System Unit Search Path

   User Unit Search Path

       A unit file is a plain text ini-style file that encodes information
       about a service, a socket, a device, a mount point, an automount point,
       a swap file or partition, a start-up target, a watched file system
       path, a timer controlled and supervised by systemd(1), a resource
       management slice or a group of externally created processes. See
       systemd.syntax(5) for a general description of the syntax.

       This man page lists the common configuration options of all the unit
       types. These options need to be configured in the [Unit] or [Install]
       sections of the unit files.

       In addition to the generic [Unit] and [Install] sections described
       here, each unit may have a type-specific section, e.g. [Service] for a
       service unit. See the respective man pages for more information:
       systemd.service(5), systemd.socket(5), systemd.device(5),
       systemd.mount(5), systemd.automount(5), systemd.swap(5),, systemd.path(5), systemd.timer(5), systemd.slice(5),

       Unit files are loaded from a set of paths determined during
       compilation, described in the next section.

       Valid unit names consist of a "name prefix" and a dot and a suffix
       specifying the unit type. The "unit prefix" must consist of one or more
       valid characters (ASCII letters, digits, ":", "-", "_", ".", and "\").
       The total length of the unit name including the suffix must not exceed
       256 characters. The type suffix must be one of ".service", ".socket",
       ".device", ".mount", ".automount", ".swap", ".target", ".path",
       ".timer", ".slice", or ".scope".

       Units names can be parameterized by a single argument called the
       "instance name". The unit is then constructed based on a "template
       file" which serves as the definition of multiple services or other
       units. A template unit must have a single "@" at the end of the name
       (right before the type suffix). The name of the full unit is formed by
       inserting the instance name between "@" and the unit type suffix. In
       the unit file itself, the instance parameter may be referred to using
       "%i" and other specifiers, see below.

       Unit files may contain additional options on top of those listed here.
       If systemd encounters an unknown option, it will write a warning log
       message but continue loading the unit. If an option or section name is
       prefixed with X-, it is ignored completely by systemd. Options within
       an ignored section do not need the prefix. Applications may use this to
       include additional information in the unit files.

       Units can be aliased (have an alternative name), by creating a symlink
       from the new name to the existing name in one of the unit search paths.
       For example, systemd-networkd.service has the alias
       dbus-org.freedesktop.network1.service, created during installation as a
       symlink, so when systemd is asked through D-Bus to load
       dbus-org.freedesktop.network1.service, it'll load
       systemd-networkd.service. As another example, — the
       default system target started at boot — is commonly symlinked (aliased)
       to either or to select what is
       started by default. Alias names may be used in commands like disable,
       start, stop, status, and similar, and in all unit dependency
       directives, including Wants=, Requires=, Before=, After=. Aliases
       cannot be used with the preset command.

       Aliases obey the following restrictions: a unit of a certain type
       (".service", ".socket", ...) can only be aliased by a name with the
       same type suffix. A plain unit (not a template or an instance), may
       only be aliased by a plain name. A template instance may only be
       aliased by another template instance, and the instance part must be
       identical. A template may be aliased by another template (in which case
       the alias applies to all instances of the template). As a special case,
       a template instance (e.g.  "alias@inst.service") may be a symlink to
       different template (e.g.  "template@inst.service"). In that case, just
       this specific instance is aliased, while other instances of the
       template (e.g.  "alias@foo.service", "alias@bar.service") are not
       aliased. Those rule preserve the requirement that the instance (if any)
       is always uniquely defined for a given unit and all its aliases.

       Unit files may specify aliases through the Alias= directive in the
       [Install] section. When the unit is enabled, symlinks will be created
       for those names, and removed when the unit is disabled. For example, specifies, so when enabled, the
       symlink /etc/systemd/systemd/ctrl-alt-del.service pointing to the file will be created, and when Ctrl+Alt+Del is invoked,
       systemd will look for the ctrl-alt-del.service and execute
       reboot.service.  systemd does not look at the [Install] section at all
       during normal operation, so any directives in that section only have an
       effect through the symlinks created during enablement.

       Along with a unit file foo.service, the directory foo.service.wants/
       may exist. All unit files symlinked from such a directory are
       implicitly added as dependencies of type Wants= to the unit. Similar
       functionality exists for Requires= type dependencies as well, the
       directory suffix is .requires/ in this case. This functionality is
       useful to hook units into the start-up of other units, without having
       to modify their unit files. For details about the semantics of Wants=,
       see below. The preferred way to create symlinks in the .wants/ or
       .requires/ directory of a unit file is by embedding the dependency in
       [Install] section of the target unit, and creating the symlink in the
       file system with the enable or preset commands of systemctl(1).

       Along with a unit file foo.service, a "drop-in" directory
       foo.service.d/ may exist. All files with the suffix ".conf" from this
       directory will be parsed after the unit file itself is parsed. This is
       useful to alter or add configuration settings for a unit, without
       having to modify unit files. Drop-in files must contain appropriate
       section headers. For instantiated units, this logic will first look for
       the instance ".d/" subdirectory (e.g.  "foo@bar.service.d/") and read
       its ".conf" files, followed by the template ".d/" subdirectory (e.g.
       "foo@.service.d/") and the ".conf" files there. Moreover for units
       names containing dashes ("-"), the set of directories generated by
       truncating the unit name after all dashes is searched too.
       Specifically, for a unit name foo-bar-baz.service not only the regular
       drop-in directory foo-bar-baz.service.d/ is searched but also both
       foo-bar-.service.d/ and foo-.service.d/. This is useful for defining
       common drop-ins for a set of related units, whose names begin with a
       common prefix. This scheme is particularly useful for mount, automount
       and slice units, whose systematic naming structure is built around
       dashes as component separators. Note that equally named drop-in files
       further down the prefix hierarchy override those further up, i.e.
       foo-bar-.service.d/10-override.conf overrides

       In cases of unit aliases (described above), dropins for the aliased
       name and all aliases are loaded. In the example of
       aliasing,,,,,, would all be read. For templates, dropins
       for the template, any template aliases, the template instance, and all
       alias instances are read. When just a specific template instance is
       aliased, then the dropins for the target template, the target template
       instance, and the alias template instance are read.

       In addition to /etc/systemd/system, the drop-in ".d/" directories for
       system services can be placed in /usr/lib/systemd/system or
       /run/systemd/system directories. Drop-in files in /etc take precedence
       over those in /run which in turn take precedence over those in
       /usr/lib. Drop-in files under any of these directories take precedence
       over unit files wherever located. Multiple drop-in files with different
       names are applied in lexicographic order, regardless of which of the
       directories they reside in.

       Units also support a top-level drop-in with type.d/, where type may be
       e.g.  "service" or "socket", that allows altering or adding to the
       settings of all corresponding unit files on the system. The formatting
       and precedence of applying drop-in configurations follow what is
       defined above. Configurations in type.d/ have the lowest precedence
       compared to settings in the name specific override directories. So the
       contents of foo-.service.d/10-override.conf would override

       Note that while systemd offers a flexible dependency system between
       units it is recommended to use this functionality only sparingly and
       instead rely on techniques such as bus-based or socket-based activation
       which make dependencies implicit, resulting in a both simpler and more
       flexible system.

       As mentioned above, a unit may be instantiated from a template file.
       This allows creation of multiple units from a single configuration
       file. If systemd looks for a unit configuration file, it will first
       search for the literal unit name in the file system. If that yields no
       success and the unit name contains an "@" character, systemd will look
       for a unit template that shares the same name but with the instance
       string (i.e. the part between the "@" character and the suffix)
       removed. Example: if a service getty@tty3.service is requested and no
       file by that name is found, systemd will look for getty@.service and
       instantiate a service from that configuration file if it is found.

       To refer to the instance string from within the configuration file you
       may use the special "%i" specifier in many of the configuration
       options. See below for details.

       If a unit file is empty (i.e. has the file size 0) or is symlinked to
       /dev/null, its configuration will not be loaded and it appears with a
       load state of "masked", and cannot be activated. Use this as an
       effective way to fully disable a unit, making it impossible to start it
       even manually.

       The unit file format is covered by the Interface Stability Promise[1].

       Sometimes it is useful to convert arbitrary strings into unit names. To
       facilitate this, a method of string escaping is used, in order to map
       strings containing arbitrary byte values (except NUL) into valid unit
       names and their restricted character set. A common special case are
       unit names that reflect paths to objects in the file system hierarchy.
       Example: a device unit dev-sda.device refers to a device with the
       device node /dev/sda in the file system.

       The escaping algorithm operates as follows: given a string, any "/"
       character is replaced by "-", and all other characters which are not
       ASCII alphanumerics or "_" are replaced by C-style "\x2d" escapes. In
       addition, "."  is replaced with such a C-style escape when it would
       appear as the first character in the escaped string.

       When the input qualifies as absolute file system path, this algorithm
       is extended slightly: the path to the root directory "/" is encoded as
       single dash "-". In addition, any leading, trailing or duplicate "/"
       characters are removed from the string before transformation. Example:
       /foo//bar/baz/ becomes "foo-bar-baz".

       This escaping is fully reversible, as long as it is known whether the
       escaped string was a path (the unescaping results are different for
       paths and non-path strings). The systemd-escape(1) command may be used
       to apply and reverse escaping on arbitrary strings. Use systemd-escape
       --path to escape path strings, and systemd-escape without --path

   Implicit Dependencies
       A number of unit dependencies are implicitly established, depending on
       unit type and unit configuration. These implicit dependencies can make
       unit configuration file cleaner. For the implicit dependencies in each
       unit type, please refer to section "Implicit Dependencies" in
       respective man pages.

       For example, service units with Type=dbus automatically acquire
       dependencies of type Requires= and After= on dbus.socket. See
       systemd.service(5) for details.

   Default Dependencies
       Default dependencies are similar to implicit dependencies, but can be
       turned on and off by setting DefaultDependencies= to yes (the default)
       and no, while implicit dependencies are always in effect. See section
       "Default Dependencies" in respective man pages for the effect of
       enabling DefaultDependencies= in each unit types.

       For example, target units will complement all configured dependencies
       of type Wants= or Requires= with dependencies of type After= unless
       DefaultDependencies=no is set in the specified units. See for details. Note that this behavior can be turned
       off by setting DefaultDependencies=no.

       Unit files are loaded from a set of paths determined during
       compilation, described in the two tables below. Unit files found in
       directories listed earlier override files with the same name in
       directories lower in the list.

       When the variable $SYSTEMD_UNIT_PATH is set, the contents of this
       variable overrides the unit load path. If $SYSTEMD_UNIT_PATH ends with
       an empty component (":"), the usual unit load path will be appended to
       the contents of the variable.

       Table 1.  Load path when running in system mode (--system).
       │Path                          Description                │
       │/etc/systemd/system.control   │ Persistent and transient   │
       ├──────────────────────────────┤ configuration created      │
       │/run/systemd/system.control   │ using the dbus API         │
       │/run/systemd/transient        │ Dynamic configuration for  │
       │                              │ transient units            │
       │/run/systemd/generator.early  │ Generated units with high  │
       │                              │ priority (see early-dir in │
       │                              │ systemd.generator(7))      │
       │/etc/systemd/system           │ System units created by    │
       │                              │ the administrator          │
       │/run/systemd/system           │ Runtime units              │
       │/run/systemd/generator        │ Generated units with       │
       │                              │ medium priority (see       │
       │                              │ normal-dir in              │
       │                              │ systemd.generator(7))      │
       │/usr/local/lib/systemd/system │ System units installed by  │
       │                              │ the administrator          │
       │/usr/lib/systemd/system       │ System units installed by  │
       │                              │ the distribution package   │
       │                              │ manager                    │
       │/run/systemd/generator.late   │ Generated units with low   │
       │                              │ priority (see late-dir in  │
       │                              │ systemd.generator(7))      │

       Table 2.  Load path when running in user mode (--user).
       │Path                                    Description                │
       │$XDG_CONFIG_HOME/systemd/user.control   │ Persistent and transient   │
       │or                                      │ configuration created      │
       │~/.config/systemd/user.control          │ using the dbus API         │
       ├────────────────────────────────────────┤ ($XDG_CONFIG_HOME is used  │
       │$XDG_RUNTIME_DIR/systemd/user.control   │ if set, ~/.config          │
       │                                        │ otherwise)                 │
       │/run/systemd/transient                  │ Dynamic configuration for  │
       │                                        │ transient units            │
       │/run/systemd/generator.early            │ Generated units with high  │
       │                                        │ priority (see early-dir in │
       │                                        │ systemd.generator(7))      │
       │$XDG_CONFIG_HOME/systemd/user or        │ User configuration         │
       │$HOME/.config/systemd/user              │ ($XDG_CONFIG_HOME is used  │
       │                                        │ if set, ~/.config          │
       │                                        │ otherwise)                 │
       │/etc/systemd/user                       │ User units created by the  │
       │                                        │ administrator              │
       │$XDG_RUNTIME_DIR/systemd/user           │ Runtime units (only used   │
       │                                        │ when $XDG_RUNTIME_DIR is   │
       │                                        │ set)                       │
       │/run/systemd/user                       │ Runtime units              │
       │$XDG_RUNTIME_DIR/systemd/generator      │ Generated units with       │
       │                                        │ medium priority (see       │
       │                                        │ normal-dir in              │
       │                                        │ systemd.generator(7))      │
       │$XDG_DATA_HOME/systemd/user or          │ Units of packages that     │
       │$HOME/.local/share/systemd/user         │ have been installed in the │
       │                                        │ home directory             │
       │                                        │ ($XDG_DATA_HOME is used if │
       │                                        │ set, ~/.local/share        │
       │                                        │ otherwise)                 │
       │$dir/systemd/user for each $dir in      │ Additional locations for   │
       │$XDG_DATA_DIRS                          │ installed user units, one  │
       │                                        │ for each entry in          │
       │                                        │ $XDG_DATA_DIRS             │
       │/usr/local/lib/systemd/user             │ User units installed by    │
       │                                        │ the administrator          │
       │/usr/lib/systemd/user                   │ User units installed by    │
       │                                        │ the distribution package   │
       │                                        │ manager                    │
       │$XDG_RUNTIME_DIR/systemd/generator.late │ Generated units with low   │
       │                                        │ priority (see late-dir in  │
       │                                        │ systemd.generator(7))      │

       The set of load paths for the user manager instance may be augmented or
       changed using various environment variables. And environment variables
       may in turn be set using environment generators, see
       systemd.environment-generator(7). In particular, $XDG_DATA_HOME and
       $XDG_DATA_DIRS may be easily set using systemd-environment-d-
       generator(8). Thus, directories listed here are just the defaults. To
       see the actual list that would be used based on compilation options and
       current environment use

           systemd-analyze --user unit-paths

       Moreover, additional units might be loaded into systemd from
       directories not on the unit load path by creating a symlink pointing to
       a unit file in the directories. You can use systemctl link for this
       operation. See systemctl(1) for its usage and precaution.

       The system and service manager loads a unit's configuration
       automatically when a unit is referenced for the first time. It will
       automatically unload the unit configuration and state again when the
       unit is not needed anymore ("garbage collection"). A unit may be
       referenced through a number of different mechanisms:

        1. Another loaded unit references it with a dependency such as After=,
           Wants=, ...

        2. The unit is currently starting, running, reloading or stopping.

        3. The unit is currently in the failed state. (But see below.)

        4. A job for the unit is pending.

        5. The unit is pinned by an active IPC client program.

        6. The unit is a special "perpetual" unit that is always active and
           loaded. Examples for perpetual units are the root mount unit
           -.mount or the scope unit init.scope that the service manager
           itself lives in.

        7. The unit has running processes associated with it.

       The garbage collection logic may be altered with the CollectMode=
       option, which allows configuration whether automatic unloading of units
       that are in failed state is permissible, see below.

       Note that when a unit's configuration and state is unloaded, all
       execution results, such as exit codes, exit signals, resource
       consumption and other statistics are lost, except for what is stored in
       the log subsystem.

       Use systemctl daemon-reload or an equivalent command to reload unit
       configuration while the unit is already loaded. In this case all
       configuration settings are flushed out and replaced with the new
       configuration (which however might not be in effect immediately),
       however all runtime state is saved/restored.

       The unit file may include a [Unit] section, which carries generic
       information about the unit that is not dependent on the type of unit:

           A human readable name for the unit. This is used by systemd (and
           other UIs) as the label for the unit, so this string should
           identify the unit rather than describe it, despite the name.
           "Apache2 Web Server" is a good example. Bad examples are
           "high-performance light-weight HTTP server" (too generic) or
           "Apache2" (too specific and meaningless for people who do not know
           Apache).  systemd will use this string as a noun in status messages
           ("Starting description...", "Started description.", "Reached target
           description.", "Failed to start description."), so it should be
           capitalized, and should not be a full sentence or a phrase with a
           continuous verb. Bad examples include "exiting the container" or
           "updating the database once per day.".

           A space-separated list of URIs referencing documentation for this
           unit or its configuration. Accepted are only URIs of the types
           "http://", "https://", "file:", "info:", "man:". For more
           information about the syntax of these URIs, see uri(7). The URIs
           should be listed in order of relevance, starting with the most
           relevant. It is a good idea to first reference documentation that
           explains what the unit's purpose is, followed by how it is
           configured, followed by any other related documentation. This
           option may be specified more than once, in which case the specified
           list of URIs is merged. If the empty string is assigned to this
           option, the list is reset and all prior assignments will have no

           Configures requirement dependencies on other units. This option may
           be specified more than once or multiple space-separated units may
           be specified in one option in which case dependencies for all
           listed names will be created. Dependencies of this type may also be
           configured outside of the unit configuration file by adding a
           symlink to a .wants/ directory accompanying the unit file. For
           details, see above.

           Units listed in this option will be started if the configuring unit
           is. However, if the listed units fail to start or cannot be added
           to the transaction, this has no impact on the validity of the
           transaction as a whole, and this unit will still be started. This
           is the recommended way to hook the start-up of one unit to the
           start-up of another unit.

           Note that requirement dependencies do not influence the order in
           which services are started or stopped. This has to be configured
           independently with the After= or Before= options. If unit
           foo.service pulls in unit bar.service as configured with Wants= and
           no ordering is configured with After= or Before=, then both units
           will be started simultaneously and without any delay between them
           if foo.service is activated.

           Similar to Wants=, but declares a stronger dependency. Dependencies
           of this type may also be configured by adding a symlink to a
           .requires/ directory accompanying the unit file.

           If this unit gets activated, the units listed will be activated as
           well. If one of the other units fails to activate, and an ordering
           dependency After= on the failing unit is set, this unit will not be
           started. Besides, with or without specifying After=, this unit will
           be stopped if one of the other units is explicitly stopped.

           Often, it is a better choice to use Wants= instead of Requires= in
           order to achieve a system that is more robust when dealing with
           failing services.

           Note that this dependency type does not imply that the other unit
           always has to be in active state when this unit is running.
           Specifically: failing condition checks (such as
           ConditionPathExists=, ConditionPathIsSymbolicLink=, ... — see
           below) do not cause the start job of a unit with a Requires=
           dependency on it to fail. Also, some unit types may deactivate on
           their own (for example, a service process may decide to exit
           cleanly, or a device may be unplugged by the user), which is not
           propagated to units having a Requires= dependency. Use the BindsTo=
           dependency type together with After= to ensure that a unit may
           never be in active state without a specific other unit also in
           active state (see below).

           Similar to Requires=. However, if the units listed here are not
           started already, they will not be started and the starting of this
           unit will fail immediately.  Requisite= does not imply an ordering
           dependency, even if both units are started in the same transaction.
           Hence this setting should usually be combined with After=, to
           ensure this unit is not started before the other unit.

           When Requisite=b.service is used on a.service, this dependency will
           show as RequisiteOf=a.service in property listing of b.service.
           RequisiteOf= dependency cannot be specified directly.

           Configures requirement dependencies, very similar in style to
           Requires=. However, this dependency type is stronger: in addition
           to the effect of Requires= it declares that if the unit bound to is
           stopped, this unit will be stopped too. This means a unit bound to
           another unit that suddenly enters inactive state will be stopped
           too. Units can suddenly, unexpectedly enter inactive state for
           different reasons: the main process of a service unit might
           terminate on its own choice, the backing device of a device unit
           might be unplugged or the mount point of a mount unit might be
           unmounted without involvement of the system and service manager.

           When used in conjunction with After= on the same unit the behaviour
           of BindsTo= is even stronger. In this case, the unit bound to
           strictly has to be in active state for this unit to also be in
           active state. This not only means a unit bound to another unit that
           suddenly enters inactive state, but also one that is bound to
           another unit that gets skipped due to a failed condition check
           (such as ConditionPathExists=, ConditionPathIsSymbolicLink=, ... —
           see below) will be stopped, should it be running. Hence, in many
           cases it is best to combine BindsTo= with After=.

           When BindsTo=b.service is used on a.service, this dependency will
           show as BoundBy=a.service in property listing of b.service.
           BoundBy= dependency cannot be specified directly.

           Configures dependencies similar to Requires=, but limited to
           stopping and restarting of units. When systemd stops or restarts
           the units listed here, the action is propagated to this unit. Note
           that this is a one-way dependency — changes to this unit do not
           affect the listed units.

           When PartOf=b.service is used on a.service, this dependency will
           show as ConsistsOf=a.service in property listing of b.service.
           ConsistsOf= dependency cannot be specified directly.

           A space-separated list of unit names. Configures negative
           requirement dependencies. If a unit has a Conflicts= setting on
           another unit, starting the former will stop the latter and vice

           Note that this setting does not imply an ordering dependency,
           similarly to the Wants= and Requires= dependencies described above.
           This means that to ensure that the conflicting unit is stopped
           before the other unit is started, an After= or Before= dependency
           must be declared. It doesn't matter which of the two ordering
           dependencies is used, because stop jobs are always ordered before
           start jobs, see the discussion in Before=/After= below.

           If unit A that conflicts with unit B is scheduled to be started at
           the same time as B, the transaction will either fail (in case both
           are required parts of the transaction) or be modified to be fixed
           (in case one or both jobs are not a required part of the
           transaction). In the latter case, the job that is not required will
           be removed, or in case both are not required, the unit that
           conflicts will be started and the unit that is conflicted is

       Before=, After=
           These two settings expect a space-separated list of unit names.
           They may be specified more than once, in which case dependencies
           for all listed names are created.

           Those two settings configure ordering dependencies between units.
           If unit foo.service contains the setting Before=bar.service and
           both units are being started, bar.service's start-up is delayed
           until foo.service has finished starting up.  After= is the inverse
           of Before=, i.e. while Before= ensures that the configured unit is
           started before the listed unit begins starting up, After= ensures
           the opposite, that the listed unit is fully started up before the
           configured unit is started.

           When two units with an ordering dependency between them are shut
           down, the inverse of the start-up order is applied. i.e. if a unit
           is configured with After= on another unit, the former is stopped
           before the latter if both are shut down. Given two units with any
           ordering dependency between them, if one unit is shut down and the
           other is started up, the shutdown is ordered before the start-up.
           It doesn't matter if the ordering dependency is After= or Before=,
           in this case. It also doesn't matter which of the two is shut down,
           as long as one is shut down and the other is started up; the
           shutdown is ordered before the start-up in all cases. If two units
           have no ordering dependencies between them, they are shut down or
           started up simultaneously, and no ordering takes place. It depends
           on the unit type when precisely a unit has finished starting up.
           Most importantly, for service units start-up is considered
           completed for the purpose of Before=/After= when all its configured
           start-up commands have been invoked and they either failed or
           reported start-up success. Note that this does includes
           ExecStartPost (or ExecStopPost for the shutdown case).

           Note that those settings are independent of and orthogonal to the
           requirement dependencies as configured by Requires=, Wants=,
           Requisite=, or BindsTo=. It is a common pattern to include a unit
           name in both the After= and Wants= options, in which case the unit
           listed will be started before the unit that is configured with
           these options.

           Note that Before= dependencies on device units have no effect and
           are not supported. Devices generally become available as a result
           of an external hotplug event, and systemd creates the corresponding
           device unit without delay.

           A space-separated list of one or more units that are activated when
           this unit enters the "failed" state. A service unit using Restart=
           enters the failed state only after the start limits are reached.

       PropagatesReloadTo=, ReloadPropagatedFrom=
           A space-separated list of one or more units where reload requests
           on this unit will be propagated to, or reload requests on the other
           unit will be propagated to this unit, respectively. Issuing a
           reload request on a unit will automatically also enqueue a reload
           request on all units that the reload request shall be propagated to
           via these two settings.

           For units that start processes (such as service units), lists one
           or more other units whose network and/or temporary file namespace
           to join. This only applies to unit types which support the
           PrivateNetwork=, NetworkNamespacePath= and PrivateTmp= directives
           (see systemd.exec(5) for details). If a unit that has this setting
           set is started, its processes will see the same /tmp, /var/tmp and
           network namespace as one listed unit that is started. If multiple
           listed units are already started, it is not defined which namespace
           is joined. Note that this setting only has an effect if
           PrivateNetwork=/NetworkNamespacePath= and/or PrivateTmp= is enabled
           for both the unit that joins the namespace and the unit whose
           namespace is joined.

           Takes a space-separated list of absolute paths. Automatically adds
           dependencies of type Requires= and After= for all mount units
           required to access the specified path.

           Mount points marked with noauto are not mounted automatically
           through, but are still honored for the purposes of
           this option, i.e. they will be pulled in by this unit.

           Takes a value of "fail", "replace", "replace-irreversibly",
           "isolate", "flush", "ignore-dependencies" or "ignore-requirements".
           Defaults to "replace". Specifies how the units listed in OnFailure=
           will be enqueued. See systemctl(1)'s --job-mode= option for details
           on the possible values. If this is set to "isolate", only a single
           unit may be listed in OnFailure=..

           Takes a boolean argument. If true, this unit will not be stopped
           when isolating another unit. Defaults to false for service, target,
           socket, busname, timer, and path units, and true for slice, scope,
           device, swap, mount, and automount units.

           Takes a boolean argument. If true, this unit will be stopped when
           it is no longer used. Note that, in order to minimize the work to
           be executed, systemd will not stop units by default unless they are
           conflicting with other units, or the user explicitly requested
           their shut down. If this option is set, a unit will be
           automatically cleaned up if no other active unit requires it.
           Defaults to false.

       RefuseManualStart=, RefuseManualStop=
           Takes a boolean argument. If true, this unit can only be activated
           or deactivated indirectly. In this case, explicit start-up or
           termination requested by the user is denied, however if it is
           started or stopped as a dependency of another unit, start-up or
           termination will succeed. This is mostly a safety feature to ensure
           that the user does not accidentally activate units that are not
           intended to be activated explicitly, and not accidentally
           deactivate units that are not intended to be deactivated. These
           options default to false.

           Takes a boolean argument. If true, this unit may be used with the
           systemctl isolate command. Otherwise, this will be refused. It
           probably is a good idea to leave this disabled except for target
           units that shall be used similar to runlevels in SysV init systems,
           just as a precaution to avoid unusable system states. This option
           defaults to false.

           Takes a boolean argument. If yes, (the default), a few default
           dependencies will implicitly be created for the unit. The actual
           dependencies created depend on the unit type. For example, for
           service units, these dependencies ensure that the service is
           started only after basic system initialization is completed and is
           properly terminated on system shutdown. See the respective man
           pages for details. Generally, only services involved with early
           boot or late shutdown should set this option to no. It is highly
           recommended to leave this option enabled for the majority of common
           units. If set to no, this option does not disable all implicit
           dependencies, just non-essential ones.

           Tweaks the "garbage collection" algorithm for this unit. Takes one
           of inactive or inactive-or-failed. If set to inactive the unit will
           be unloaded if it is in the inactive state and is not referenced by
           clients, jobs or other units — however it is not unloaded if it is
           in the failed state. In failed mode, failed units are not unloaded
           until the user invoked systemctl reset-failed on them to reset the
           failed state, or an equivalent command. This behaviour is altered
           if this option is set to inactive-or-failed: in this case the unit
           is unloaded even if the unit is in a failed state, and thus an
           explicitly resetting of the failed state is not necessary. Note
           that if this mode is used unit results (such as exit codes, exit
           signals, consumed resources, ...) are flushed out immediately after
           the unit completed, except for what is stored in the logging
           subsystem. Defaults to inactive.

       FailureAction=, SuccessAction=
           Configure the action to take when the unit stops and enters a
           failed state or inactive state. Takes one of none, reboot,
           reboot-force, reboot-immediate, poweroff, poweroff-force,
           poweroff-immediate, exit, and exit-force. In system mode, all
           options are allowed. In user mode, only none, exit, and exit-force
           are allowed. Both options default to none.

           If none is set, no action will be triggered.  reboot causes a
           reboot following the normal shutdown procedure (i.e. equivalent to
           systemctl reboot).  reboot-force causes a forced reboot which will
           terminate all processes forcibly but should cause no dirty file
           systems on reboot (i.e. equivalent to systemctl reboot -f) and
           reboot-immediate causes immediate execution of the reboot(2) system
           call, which might result in data loss (i.e. equivalent to systemctl
           reboot -ff). Similarly, poweroff, poweroff-force,
           poweroff-immediate have the effect of powering down the system with
           similar semantics.  exit causes the manager to exit following the
           normal shutdown procedure, and exit-force causes it terminate
           without shutting down services. When exit or exit-force is used by
           default the exit status of the main process of the unit (if this
           applies) is returned from the service manager. However, this may be
           overridden with FailureActionExitStatus=/SuccessActionExitStatus=,
           see below.

       FailureActionExitStatus=, SuccessActionExitStatus=
           Controls the exit status to propagate back to an invoking container
           manager (in case of a system service) or service manager (in case
           of a user manager) when the FailureAction=/SuccessAction= are set
           to exit or exit-force and the action is triggered. By default the
           exit status of the main process of the triggering unit (if this
           applies) is propagated. Takes a value in the range 0...255 or the
           empty string to request default behaviour.

       JobTimeoutSec=, JobRunningTimeoutSec=
           When a job for this unit is queued, a timeout JobTimeoutSec= may be
           configured. Similarly, JobRunningTimeoutSec= starts counting when
           the queued job is actually started. If either time limit is
           reached, the job will be cancelled, the unit however will not
           change state or even enter the "failed" mode. This value defaults
           to "infinity" (job timeouts disabled), except for device units
           (JobRunningTimeoutSec= defaults to DefaultTimeoutStartSec=). NB:
           this timeout is independent from any unit-specific timeout (for
           example, the timeout set with TimeoutStartSec= in service units) as
           the job timeout has no effect on the unit itself, only on the job
           that might be pending for it. Or in other words: unit-specific
           timeouts are useful to abort unit state changes, and revert them.
           The job timeout set with this option however is useful to abort
           only the job waiting for the unit state to change.

       JobTimeoutAction=, JobTimeoutRebootArgument=
           JobTimeoutAction= optionally configures an additional action to
           take when the timeout is hit, see description of JobTimeoutSec= and
           JobRunningTimeoutSec= above. It takes the same values as
           StartLimitAction=. Defaults to none.  JobTimeoutRebootArgument=
           configures an optional reboot string to pass to the reboot(2)
           system call.

       StartLimitIntervalSec=interval, StartLimitBurst=burst
           Configure unit start rate limiting. Units which are started more
           than burst times within an interval time interval are not permitted
           to start any more. Use StartLimitIntervalSec= to configure the
           checking interval (defaults to DefaultStartLimitIntervalSec= in
           manager configuration file, set it to 0 to disable any kind of rate
           limiting). Use StartLimitBurst= to configure how many starts per
           interval are allowed (defaults to DefaultStartLimitBurst= in
           manager configuration file). These configuration options are
           particularly useful in conjunction with the service setting
           Restart= (see systemd.service(5)); however, they apply to all kinds
           of starts (including manual), not just those triggered by the
           Restart= logic. Note that units which are configured for Restart=
           and which reach the start limit are not attempted to be restarted
           anymore; however, they may still be restarted manually at a later
           point, after the interval has passed. From this point on, the
           restart logic is activated again. Note that systemctl reset-failed
           will cause the restart rate counter for a service to be flushed,
           which is useful if the administrator wants to manually start a unit
           and the start limit interferes with that. Note that this
           rate-limiting is enforced after any unit condition checks are
           executed, and hence unit activations with failing conditions do not
           count towards this rate limit. This setting does not apply to
           slice, target, device, and scope units, since they are unit types
           whose activation may either never fail, or may succeed only a
           single time.

           When a unit is unloaded due to the garbage collection logic (see
           above) its rate limit counters are flushed out too. This means that
           configuring start rate limiting for a unit that is not referenced
           continuously has no effect.

           Configure an additional action to take if the rate limit configured
           with StartLimitIntervalSec= and StartLimitBurst= is hit. Takes the
           same values as the setting FailureAction=/SuccessAction= settings
           and executes the same actions. If none is set, hitting the rate
           limit will trigger no action besides that the start will not be
           permitted. Defaults to none.

           Configure the optional argument for the reboot(2) system call if
           StartLimitAction= or FailureAction= is a reboot action. This works
           just like the optional argument to systemctl reboot command.

           A path to a configuration file this unit has been generated from.
           This is primarily useful for implementation of generator tools that
           convert configuration from an external configuration file format
           into native unit files. This functionality should not be used in
           normal units.

   Conditions and Asserts
       Unit files may also include a number of Condition...= and Assert...=
       settings. Before the unit is started, systemd will verify that the
       specified conditions are true. If not, the starting of the unit will be
       (mostly silently) skipped. Failing conditions will not result in the
       unit being moved into the "failed" state. The conditions are checked at
       the time the queued start job is to be executed. The ordering
       dependencies are still respected, so other units are still pulled in
       and ordered as if this unit was successfully activated. Use condition
       expressions in order to skip units that do not apply to the local
       system, for example because the kernel or runtime environment doesn't
       require their functionality.

       If multiple conditions are specified, the unit will be executed if all
       of them apply (i.e. a logical AND is applied). Condition checks can use
       a pipe symbol ("|") after the equals sign ("Condition...=|..."), which
       causes the condition becomes a triggering condition. If at least one
       triggering condition is defined for a unit, then the unit will be
       executed if at least one of the triggering conditions apply and all of
       the non-triggering conditions. If you prefix an argument with the pipe
       symbol and an exclamation mark, the pipe symbol must be passed first,
       the exclamation second. If any of these options is assigned the empty
       string, the list of conditions is reset completely, all previous
       condition settings (of any kind) will have no effect.

       The AssertArchitecture=, AssertVirtualization=, ... options provide a
       similar mechanism that causes the job to fail (instead of being
       skipped). The failed check is logged. Units with failed conditions are
       considered to be in a clean state and will be garbage collected if they
       are not referenced. This means that when queried, the condition failure
       may or may not show up in the state of the unit.

       Note that neither assertion nor condition expressions result in unit
       state changes. Also note that both are checked at the time the job is
       to be executed, i.e. long after depending jobs and it itself were
       queued. Thus, neither condition nor assertion expressions are suitable
       for conditionalizing unit dependencies.

       The condition verb of systemd-analyze(1) can be used to test condition
       and assert expressions.

       Except for ConditionPathIsSymbolicLink=, all path checks follow

           Check whether the system is running on a specific architecture.
           Takes one of "x86", "x86-64", "ppc", "ppc-le", "ppc64", "ppc64-le",
           "ia64", "parisc", "parisc64", "s390", "s390x", "sparc", "sparc64",
           "mips", "mips-le", "mips64", "mips64-le", "alpha", "arm", "arm-be",
           "arm64", "arm64-be", "sh", "sh64", "m68k", "tilegx", "cris", "arc",
           "arc-be", or "native".

           The architecture is determined from the information returned by
           uname(2) and is thus subject to personality(2). Note that a
           Personality= setting in the same unit file has no effect on this
           condition. A special architecture name "native" is mapped to the
           architecture the system manager itself is compiled for. The test
           may be negated by prepending an exclamation mark.

           Check whether the system is executed in a virtualized environment
           and optionally test whether it is a specific implementation. Takes
           either boolean value to check if being executed in any virtualized
           environment, or one of "vm" and "container" to test against a
           generic type of virtualization solution, or one of "qemu", "kvm",
           "zvm", "vmware", "microsoft", "oracle", "xen", "bochs", "uml",
           "bhyve", "qnx", "openvz", "lxc", "lxc-libvirt", "systemd-nspawn",
           "docker", "podman", "rkt", "wsl", "acrn" to test against a specific
           implementation, or "private-users" to check whether we are running
           in a user namespace. See systemd-detect-virt(1) for a full list of
           known virtualization technologies and their identifiers. If
           multiple virtualization technologies are nested, only the innermost
           is considered. The test may be negated by prepending an exclamation

           ConditionHost= may be used to match against the hostname or machine
           ID of the host. This either takes a hostname string (optionally
           with shell style globs) which is tested against the locally set
           hostname as returned by gethostname(2), or a machine ID formatted
           as string (see machine-id(5)). The test may be negated by
           prepending an exclamation mark.

           ConditionKernelCommandLine= may be used to check whether a specific
           kernel command line option is set (or if prefixed with the
           exclamation mark — unset). The argument must either be a single
           word, or an assignment (i.e. two words, separated by "="). In the
           former case the kernel command line is searched for the word
           appearing as is, or as left hand side of an assignment. In the
           latter case, the exact assignment is looked for with right and left
           hand side matching.

           ConditionKernelVersion= may be used to check whether the kernel
           version (as reported by uname -r) matches a certain expression (or
           if prefixed with the exclamation mark does not match it). The
           argument must be a list of (potentially quoted) expressions. For
           each of the expressions, if it starts with one of "<", "<=", "=",
           "!=", ">=", ">" a relative version comparison is done, otherwise
           the specified string is matched with shell-style globs.

           Note that using the kernel version string is an unreliable way to
           determine which features are supported by a kernel, because of the
           widespread practice of backporting drivers, features, and fixes
           from newer upstream kernels into older versions provided by
           distributions. Hence, this check is inherently unportable and
           should not be used for units which may be used on different

           ConditionSecurity= may be used to check whether the given security
           technology is enabled on the system. Currently, the recognized
           values are "selinux", "apparmor", "tomoyo", "ima", "smack", "audit"
           and "uefi-secureboot". The test may be negated by prepending an
           exclamation mark.

           Check whether the given capability exists in the capability
           bounding set of the service manager (i.e. this does not check
           whether capability is actually available in the permitted or
           effective sets, see capabilities(7) for details). Pass a capability
           name such as "CAP_MKNOD", possibly prefixed with an exclamation
           mark to negate the check.

           Check whether the system has AC power, or is exclusively battery
           powered at the time of activation of the unit. This takes a boolean
           argument. If set to "true", the condition will hold only if at
           least one AC connector of the system is connected to a power
           source, or if no AC connectors are known. Conversely, if set to
           "false", the condition will hold only if there is at least one AC
           connector known and all AC connectors are disconnected from a power

           Takes one of /var or /etc as argument, possibly prefixed with a "!"
           (to invert the condition). This condition may be used to
           conditionalize units on whether the specified directory requires an
           update because /usr's modification time is newer than the stamp
           file .updated in the specified directory. This is useful to
           implement offline updates of the vendor operating system resources
           in /usr that require updating of /etc or /var on the next following
           boot. Units making use of this condition should order themselves
           before systemd-update-done.service(8), to make sure they run before
           the stamp file's modification time gets reset indicating a
           completed update.

           Takes a boolean argument. This condition may be used to
           conditionalize units on whether the system is booting up with an
           unpopulated /etc directory (specifically: an /etc with no
           /etc/machine-id). This may be used to populate /etc on the first
           boot after factory reset, or when a new system instance boots up
           for the first time.

           Check for the exists of a file. If the specified absolute path name
           does not exist, the condition will fail. If the absolute path name
           passed to ConditionPathExists= is prefixed with an exclamation mark
           ("!"), the test is negated, and the unit is only started if the
           path does not exist.

           ConditionPathExistsGlob= is similar to ConditionPathExists=, but
           checks for the existence of at least one file or directory matching
           the specified globbing pattern.

           ConditionPathIsDirectory= is similar to ConditionPathExists= but
           verifies that a certain path exists and is a directory.

           ConditionPathIsSymbolicLink= is similar to ConditionPathExists= but
           verifies that a certain path exists and is a symbolic link.

           ConditionPathIsMountPoint= is similar to ConditionPathExists= but
           verifies that a certain path exists and is a mount point.

           ConditionPathIsReadWrite= is similar to ConditionPathExists= but
           verifies that the underlying file system is readable and writable
           (i.e. not mounted read-only).

           ConditionDirectoryNotEmpty= is similar to ConditionPathExists= but
           verifies that a certain path exists and is a non-empty directory.

           ConditionFileNotEmpty= is similar to ConditionPathExists= but
           verifies that a certain path exists and refers to a regular file
           with a non-zero size.

           ConditionFileIsExecutable= is similar to ConditionPathExists= but
           verifies that a certain path exists, is a regular file, and marked

           ConditionUser= takes a numeric "UID", a UNIX user name, or the
           special value "@system". This condition may be used to check
           whether the service manager is running as the given user. The
           special value "@system" can be used to check if the user id is
           within the system user range. This option is not useful for system
           services, as the system manager exclusively runs as the root user,
           and thus the test result is constant.

           ConditionGroup= is similar to ConditionUser= but verifies that the
           service manager's real or effective group, or any of its auxiliary
           groups, match the specified group or GID. This setting does not
           support the special value "@system".

           Verify that the given cgroup controller (eg.  "cpu") is available
           for use on the system. For example, a particular controller may not
           be available if it was disabled on the kernel command line with
           cgroup_disable=controller. Multiple controllers may be passed with
           a space separating them; in this case the condition will only pass
           if all listed controllers are available for use. Controllers
           unknown to systemd are ignored. Valid controllers are "cpu",
           "cpuacct", "io", "blkio", "memory", "devices", and "pids".

           Verify that the specified amount of system memory is available to
           the current system. Takes a memory size in bytes as argument,
           optionally prefixed with a comparison operator "<", "<=", "=",
           "!=", ">=", ">". On bare-metal systems compares the amount of
           physical memory in the system with the specified size, adhering to
           the specified comparison operator. In containers compares the
           amount of memory assigned to the container instead.

           Verify that the specified number of CPUs is available to the
           current system. Takes a number of CPUs as argument, optionally
           prefixed with a comparison operator "<", "<=", "=", "!=", ">=",
           ">". Compares the number of CPUs in the CPU affinity mask
           configured of the service manager itself with the specified number,
           adhering to the specified comparison operator. On physical systems
           the number of CPUs in the affinity mask of the service manager
           usually matches the number of physical CPUs, but in special and
           virtual environments might differ. In particular, in containers the
           affinity mask usually matches the number of CPUs assigned to the
           container and not the physically available ones.

       AssertArchitecture=, AssertVirtualization=, AssertHost=,
       AssertKernelCommandLine=, AssertKernelVersion=, AssertSecurity=,
       AssertCapability=, AssertACPower=, AssertNeedsUpdate=,
       AssertFirstBoot=, AssertPathExists=, AssertPathExistsGlob=,
       AssertPathIsDirectory=, AssertPathIsSymbolicLink=,
       AssertPathIsMountPoint=, AssertPathIsReadWrite=,
       AssertDirectoryNotEmpty=, AssertFileNotEmpty=, AssertFileIsExecutable=,
       AssertUser=, AssertGroup=, AssertControlGroupController=
           Similar to the ConditionArchitecture=, ConditionVirtualization=,
           ..., condition settings described above, these settings add
           assertion checks to the start-up of the unit. However, unlike the
           conditions settings, any assertion setting that is not met results
           in failure of the start job (which means this is logged loudly).
           Note that hitting a configured assertion does not cause the unit to
           enter the "failed" state (or in fact result in any state change of
           the unit), it affects only the job queued for it. Use assertion
           expressions for units that cannot operate when specific
           requirements are not met, and when this is something the
           administrator or user should look into.

       Unit settings that create a relationship with a second unit usually
       show up in properties of both units, for example in systemctl show
       output. In some cases the name of the property is the same as the name
       of the configuration setting, but not always. This table lists the
       properties that are shown on two units which are connected through some
       dependency, and shows which property on "source" unit corresponds to
       which property on the "target" unit.

       Table 3.  Forward and reverse unit properties
       │"Forward"             "Reverse"             Where used                      │
       │property              property              │                                 │
       │Before=               After=                │                                 │
       ├──────────────────────┼───────────────────────┤ [Unit] section                  │
       │After=                Before=               │                                 │
       │Requires=             RequiredBy=           │ [Unit] section  │ [Install]     │
       │                      │                       │                 │ section       │
       │Wants=                WantedBy=             │ [Unit] section  │ [Install]     │
       │                      │                       │                 │ section       │
       │PartOf=               ConsistsOf=           │ [Unit] section  │ an automatic  │
       │                      │                       │                 │ property      │
       │BindsTo=              BoundBy=              │ [Unit] section  │ an automatic  │
       │                      │                       │                 │ property      │
       │Requisite=            RequisiteOf=          │ [Unit] section  │ an automatic  │
       │                      │                       │                 │ property      │
       │Triggers=             TriggeredBy=          │ Automatic properties, see notes │
       │                      │                       │ below                           │
       │Conflicts=            ConflictedBy=         │ [Unit] section  │ an automatic  │
       │                      │                       │                 │ property      │
       │PropagatesReloadTo=   ReloadPropagatedFrom= │                                 │
       ├──────────────────────┼───────────────────────┤ [Unit] section                  │
       │ReloadPropagatedFrom= PropagatesReloadTo=   │                                 │
       │Following=            │ n/a                   │ An automatic    │               │
       │                      │                       │ property        │               │

       Note: WantedBy= and RequiredBy= are used in the [Install] section to
       create symlinks in .wants/ and .requires/ directories. They cannot be
       used directly as a unit configuration setting.

       Note: ConsistsOf=, BoundBy=, RequisiteOf=, ConflictedBy= are created
       implicitly along with their reverses and cannot be specified directly.

       Note: Triggers= is created implicitly between a socket, path unit, or
       an automount unit, and the unit they activate. By default a unit with
       the same name is triggered, but this can be overridden using Sockets=,
       Service=, and Unit= settings. See systemd.service(5),
       systemd.socket(5), systemd.path(5), and systemd.automount(5) for
       details.  TriggeredBy= is created implicitly on the triggered unit.

       Note: Following= is used to group device aliases and points to the
       "primary" device unit that systemd is using to track device state,
       usually corresponding to a sysfs path. It does not show up in the
       "target" unit.

       Unit files may include an "[Install]" section, which carries
       installation information for the unit. This section is not interpreted
       by systemd(1) during runtime; it is used by the enable and disable
       commands of the systemctl(1) tool during installation of a unit.

           A space-separated list of additional names this unit shall be
           installed under. The names listed here must have the same suffix
           (i.e. type) as the unit filename. This option may be specified more
           than once, in which case all listed names are used. At installation
           time, systemctl enable will create symlinks from these names to the
           unit filename. Note that not all unit types support such alias
           names, and this setting is not supported for them. Specifically,
           mount, slice, swap, and automount units do not support aliasing.

       WantedBy=, RequiredBy=
           This option may be used more than once, or a space-separated list
           of unit names may be given. A symbolic link is created in the
           .wants/ or .requires/ directory of each of the listed units when
           this unit is installed by systemctl enable. This has the effect
           that a dependency of type Wants= or Requires= is added from the
           listed unit to the current unit. The primary result is that the
           current unit will be started when the listed unit is started. See
           the description of Wants= and Requires= in the [Unit] section for

           WantedBy=foo.service in a service bar.service is mostly equivalent
           to Alias=foo.service.wants/bar.service in the same file. In case of
           template units, systemctl enable must be called with an instance
           name, and this instance will be added to the .wants/ or .requires/
           list of the listed unit. E.g. in a service
           getty@.service will result in systemctl enable getty@tty2.service
           creating a link to

           Additional units to install/deinstall when this unit is
           installed/deinstalled. If the user requests
           installation/deinstallation of a unit with this option configured,
           systemctl enable and systemctl disable will automatically
           install/uninstall units listed in this option as well.

           This option may be used more than once, or a space-separated list
           of unit names may be given.

           In template unit files, this specifies for which instance the unit
           shall be enabled if the template is enabled without any explicitly
           set instance. This option has no effect in non-template unit files.
           The specified string must be usable as instance identifier.

       The following specifiers are interpreted in the Install section: %n,
       %N, %p, %i, %j, %g, %G, %U, %u, %m, %H, %b, %v. For their meaning see
       the next section.

       Many settings resolve specifiers which may be used to write generic
       unit files referring to runtime or unit parameters that are replaced
       when the unit files are loaded. Specifiers must be known and resolvable
       for the setting to be valid. The following specifiers are understood:

       Table 4. Specifiers available in unit files
       │Specifier Meaning             Details             │
       │"%b"      │ Boot ID             │ The boot ID of the  │
       │          │                     │ running system,     │
       │          │                     │ formatted as        │
       │          │                     │ string. See         │
       │          │                     │ random(4) for more  │
       │          │                     │ information.        │
       │"%C"      │ Cache directory     │ This is either      │
       │          │ root                │ /var/cache (for the │
       │          │                     │ system manager) or  │
       │          │                     │ the path            │
       │          │                     │ "$XDG_CACHE_HOME"   │
       │          │                     │ resolves to (for    │
       │          │                     │ user managers).     │
       │"%E"      │ Configuration       │ This is either /etc │
       │          │ directory root      │ (for the system     │
       │          │                     │ manager) or the     │
       │          │                     │ path                │
       │          │                     │ "$XDG_CONFIG_HOME"  │
       │          │                     │ resolves to (for    │
       │          │                     │ user managers).     │
       │"%f"      │ Unescaped filename  │ This is either the  │
       │          │                     │ unescaped instance  │
       │          │                     │ name (if            │
       │          │                     │ applicable) with /  │
       │          │                     │ prepended (if       │
       │          │                     │ applicable), or the │
       │          │                     │ unescaped prefix    │
       │          │                     │ name prepended with │
       │          │                     │ /. This implements  │
       │          │                     │ unescaping          │
       │          │                     │ according to the    │
       │          │                     │ rules for escaping  │
       │          │                     │ absolute file       │
       │          │                     │ system paths        │
       │          │                     │ discussed above.    │
       │"%h"      │ User home directory │ This is the home    │
       │          │                     │ directory of the    │
       │          │                     │ user running the    │
       │          │                     │ service manager     │
       │          │                     │ instance. In case   │
       │          │                     │ of the system       │
       │          │                     │ manager this        │
       │          │                     │ resolves to         │
       │          │                     │ "/root".            │
       │          │                     │                     │
       │          │                     │ Note that this      │
       │          │                     │ setting is not      │
       │          │                     │ influenced by the   │
       │          │                     │ User= setting       │
       │          │                     │ configurable in the │
       │          │                     │ [Service] section   │
       │          │                     │ of the service      │
       │          │                     │ unit.               │
       │"%H"      │ Host name           │ The hostname of the │
       │          │                     │ running system at   │
       │          │                     │ the point in time   │
       │          │                     │ the unit            │
       │          │                     │ configuration is    │
       │          │                     │ loaded.             │
       │"%i"      │ Instance name       │ For instantiated    │
       │          │                     │ units this is the   │
       │          │                     │ string between the  │
       │          │                     │ first "@" character │
       │          │                     │ and the type        │
       │          │                     │ suffix. Empty for   │
       │          │                     │ non-instantiated    │
       │          │                     │ units.              │
       │"%I"      │ Unescaped instance  │ Same as "%i", but   │
       │          │ name                │ with escaping       │
       │          │                     │ undone.             │
       │"%j"      │ Final component of  │ This is the string  │
       │          │ the prefix          │ between the last    │
       │          │                     │ "-" and the end of  │
       │          │                     │ the prefix name. If │
       │          │                     │ there is no "-",    │
       │          │                     │ this is the same as │
       │          │                     │ "%p".               │
       │"%J"      │ Unescaped final     │ Same as "%j", but   │
       │          │ component of the    │ with escaping       │
       │          │ prefix              │ undone.             │
       │"%L"      │ Log directory root  │ This is either      │
       │          │                     │ /var/log (for the   │
       │          │                     │ system manager) or  │
       │          │                     │ the path            │
       │          │                     │ "$XDG_CONFIG_HOME"  │
       │          │                     │ resolves to with    │
       │          │                     │ /log appended (for  │
       │          │                     │ user managers).     │
       │"%m"      │ Machine ID          │ The machine ID of   │
       │          │                     │ the running system, │
       │          │                     │ formatted as        │
       │          │                     │ string. See         │
       │          │                     │ machine-id(5) for   │
       │          │                     │ more information.   │
       │"%n"      │ Full unit name      │                     │
       │"%N"      │ Full unit name      │ Same as "%n", but   │
       │          │                     │ with the type       │
       │          │                     │ suffix removed.     │
       │"%p"      │ Prefix name         │ For instantiated    │
       │          │                     │ units, this refers  │
       │          │                     │ to the string       │
       │          │                     │ before the first    │
       │          │                     │ "@" character of    │
       │          │                     │ the unit name. For  │
       │          │                     │ non-instantiated    │
       │          │                     │ units, same as      │
       │          │                     │ "%N".               │
       │"%P"      │ Unescaped prefix    │ Same as "%p", but   │
       │          │ name                │ with escaping       │
       │          │                     │ undone.             │
       │"%s"      │ User shell          │ This is the shell   │
       │          │                     │ of the user running │
       │          │                     │ the service manager │
       │          │                     │ instance. In case   │
       │          │                     │ of the system       │
       │          │                     │ manager this        │
       │          │                     │ resolves to         │
       │          │                     │ "/bin/sh".          │
       │"%S"      │ State directory     │ This is either      │
       │          │ root                │ /var/lib (for the   │
       │          │                     │ system manager) or  │
       │          │                     │ the path            │
       │          │                     │ "$XDG_CONFIG_HOME"  │
       │          │                     │ resolves to (for    │
       │          │                     │ user managers).     │
       │"%t"      │ Runtime directory   │ This is either /run │
       │          │ root                │ (for the system     │
       │          │                     │ manager) or the     │
       │          │                     │ path                │
       │          │                     │ "$XDG_RUNTIME_DIR"  │
       │          │                     │ resolves to (for    │
       │          │                     │ user managers).     │
       │"%T"      │ Directory for       │ This is either /tmp │
       │          │ temporary files     │ or the path         │
       │          │                     │ "$TMPDIR", "$TEMP"  │
       │          │                     │ or "$TMP" are set   │
       │          │                     │ to.                 │
       │"%g"      │ User group          │ This is the name of │
       │          │                     │ the group running   │
       │          │                     │ the service manager │
       │          │                     │ instance. In case   │
       │          │                     │ of the system       │
       │          │                     │ manager this        │
       │          │                     │ resolves to "root". │
       │"%G"      │ User GID            │ This is the numeric │
       │          │                     │ GID of the user     │
       │          │                     │ running the service │
       │          │                     │ manager instance.   │
       │          │                     │ In case of the      │
       │          │                     │ system manager this │
       │          │                     │ resolves to "0".    │
       │"%u"      │ User name           │ This is the name of │
       │          │                     │ the user running    │
       │          │                     │ the service manager │
       │          │                     │ instance. In case   │
       │          │                     │ of the system       │
       │          │                     │ manager this        │
       │          │                     │ resolves to "root". │
       │          │                     │                     │
       │          │                     │ Note that this      │
       │          │                     │ setting is not      │
       │          │                     │ influenced by the   │
       │          │                     │ User= setting       │
       │          │                     │ configurable in the │
       │          │                     │ [Service] section   │
       │          │                     │ of the service      │
       │          │                     │ unit.               │
       │"%U"      │ User UID            │ This is the numeric │
       │          │                     │ UID of the user     │
       │          │                     │ running the service │
       │          │                     │ manager instance.   │
       │          │                     │ In case of the      │
       │          │                     │ system manager this │
       │          │                     │ resolves to "0".    │
       │          │                     │                     │
       │          │                     │ Note that this      │
       │          │                     │ setting is not      │
       │          │                     │ influenced by the   │
       │          │                     │ User= setting       │
       │          │                     │ configurable in the │
       │          │                     │ [Service] section   │
       │          │                     │ of the service      │
       │          │                     │ unit.               │
       │"%v"      │ Kernel release      │ Identical to uname  │
       │          │                     │ -r output           │
       │"%V"      │ Directory for       │ This is either      │
       │          │ larger and          │ /var/tmp or the     │
       │          │ persistent          │ path "$TMPDIR",     │
       │          │ temporary files     │ "$TEMP" or "$TMP"   │
       │          │                     │ are set to.         │
       │"%%"      │ Single percent sign │ Use "%%" in place   │
       │          │                     │ of "%" to specify a │
       │          │                     │ single percent      │
       │          │                     │ sign.               │

       Example 1. Allowing units to be enabled

       The following snippet (highlighted) allows a unit (e.g.  foo.service)
       to be enabled via systemctl enable:




       After running systemctl enable, a symlink
       /etc/systemd/system/ linking to the
       actual unit will be created. It tells systemd to pull in the unit when
       starting The inverse systemctl disable will remove
       that symlink again.

       Example 2. Overriding vendor settings

       There are two methods of overriding vendor settings in unit files:
       copying the unit file from /usr/lib/systemd/system to
       /etc/systemd/system and modifying the chosen settings. Alternatively,
       one can create a directory named unit.d/ within /etc/systemd/system and
       place a drop-in file name.conf there that only changes the specific
       settings one is interested in. Note that multiple such drop-in files
       are read if present, processed in lexicographic order of their

       The advantage of the first method is that one easily overrides the
       complete unit, the vendor unit is not parsed at all anymore. It has the
       disadvantage that improvements to the unit file by the vendor are not
       automatically incorporated on updates.

       The advantage of the second method is that one only overrides the
       settings one specifically wants, where updates to the unit by the
       vendor automatically apply. This has the disadvantage that some future
       updates by the vendor might be incompatible with the local changes.

       This also applies for user instances of systemd, but with different
       locations for the unit files. See the section on unit load paths for
       further details.

       Suppose there is a vendor-supplied unit
       /usr/lib/systemd/system/httpd.service with the following contents:

           Description=Some HTTP server



       Now one wants to change some settings as an administrator: firstly, in
       the local setup, /srv/webserver might not exist, because the HTTP
       server is configured to use /srv/www instead. Secondly, the local
       configuration makes the HTTP server also depend on a memory cache
       service, memcached.service, that should be pulled in (Requires=) and
       also be ordered appropriately (After=). Thirdly, in order to harden the
       service a bit more, the administrator would like to set the PrivateTmp=
       setting (see systemd.exec(5) for details). And lastly, the
       administrator would like to reset the niceness of the service to its
       default value of 0.

       The first possibility is to copy the unit file to
       /etc/systemd/system/httpd.service and change the chosen settings:

           Description=Some HTTP server
  sqldb.service memcached.service
           Requires=sqldb.service memcached.service



       Alternatively, the administrator could create a drop-in file
       /etc/systemd/system/httpd.service.d/local.conf with the following

           # Reset all assertions and then re-add the condition we want


       Note that for drop-in files, if one wants to remove entries from a
       setting that is parsed as a list (and is not a dependency), such as
       AssertPathExists= (or e.g.  ExecStart= in service units), one needs to
       first clear the list before re-adding all entries except the one that
       is to be removed. Dependencies (After=, etc.) cannot be reset to an
       empty list, so dependencies can only be added in drop-ins. If you want
       to remove dependencies, you have to override the entire unit.

       systemd(1), systemctl(1), systemd-system.conf(5), systemd.special(7),
       systemd.service(5), systemd.socket(5), systemd.device(5),
       systemd.mount(5), systemd.automount(5), systemd.swap(5),, systemd.path(5), systemd.timer(5), systemd.scope(5),
       systemd.slice(5), systemd.time(7), systemd-analyze(1), capabilities(7),
       systemd.directives(7), uname(1)

        1. Interface Stability Promise

systemd 245                                                    SYSTEMD.UNIT(5)