NAME

       systemd.path - Path unit configuration

SYNOPSIS

       path.path

DESCRIPTION

       A unit configuration file whose name ends in ".path" encodes information about a path
       monitored by systemd, for path-based activation.

       This man page lists the configuration options specific to this unit type. See
       systemd.unit(5) for the common options of all unit configuration files. The common
       configuration items are configured in the generic [Unit] and [Install] sections. The path
       specific configuration options are configured in the [Path] section.

       For each path file, a matching unit file must exist, describing the unit to activate when
       the path changes. By default, a service by the same name as the path (except for the
       suffix) is activated. Example: a path file foo.path activates a matching service
       foo.service. The unit to activate may be controlled by Unit= (see below).

       Internally, path units use the inotify(7) API to monitor file systems. Due to that, it
       suffers by the same limitations as inotify, and for example cannot be used to monitor
       files or directories changed by other machines on remote NFS file systems.

       When a service unit triggered by a path unit terminates (regardless whether it exited
       successfully or failed), monitored paths are checked immediately again, and the service
       accordingly restarted instantly. As protection against busy looping in this trigger/start
       cycle, a start rate limit is enforced on the service unit, see StartLimitIntervalSec= and
       StartLimitBurst= in systemd.unit(5). Unlike other service failures, the error condition
       that the start rate limit is hit is propagated from the service unit to the path unit and
       causes the path unit to fail as well, thus ending the loop.

AUTOMATIC DEPENDENCIES

   Implicit Dependencies
       The following dependencies are implicitly added:

       •   If a path unit is beneath another mount unit in the file system hierarchy, both a
           requirement and an ordering dependency between both units are created automatically.

       •   An implicit Before= dependency is added between a path unit and the unit it is
           supposed to activate.

   Default Dependencies
       The following dependencies are added unless DefaultDependencies=no is set:

       •   Path units will automatically have dependencies of type Before= on paths.target,
           dependencies of type After= and Requires= on sysinit.target, and have dependencies of
           type Conflicts= and Before= on shutdown.target. These ensure that path units are
           terminated cleanly prior to system shutdown. Only path units involved with early boot
           or late system shutdown should disable DefaultDependencies= option.

OPTIONS

       Path unit files may include [Unit] and [Install] sections, which are described in
       systemd.unit(5).

       Path unit files must include a [Path] section, which carries information about the path or
       paths it monitors. The options specific to the [Path] section of path units are the
       following:

       PathExists=, PathExistsGlob=, PathChanged=, PathModified=, DirectoryNotEmpty=
           Defines paths to monitor for certain changes: PathExists= may be used to watch the
           mere existence of a file or directory. If the file specified exists, the configured
           unit is activated.  PathExistsGlob= works similarly, but checks for the existence of
           at least one file matching the globbing pattern specified.  PathChanged= may be used
           to watch a file or directory and activate the configured unit whenever it changes. It
           is not activated on every write to the watched file but it is activated if the file
           which was open for writing gets closed.  PathModified= is similar, but additionally it
           is activated also on simple writes to the watched file.  DirectoryNotEmpty= may be
           used to watch a directory and activate the configured unit whenever it contains at
           least one file.

           The arguments of these directives must be absolute file system paths.

           Multiple directives may be combined, of the same and of different types, to watch
           multiple paths. If the empty string is assigned to any of these options, the list of
           paths to watch is reset, and any prior assignments of these options will not have any
           effect.

           If a path already exists (in case of PathExists= and PathExistsGlob=) or a directory
           already is not empty (in case of DirectoryNotEmpty=) at the time the path unit is
           activated, then the configured unit is immediately activated as well. Something
           similar does not apply to PathChanged= and PathModified=.

           If the path itself or any of the containing directories are not accessible, systemd
           will watch for permission changes and notice that conditions are satisfied when
           permissions allow that.

       Unit=
           The unit to activate when any of the configured paths changes. The argument is a unit
           name, whose suffix is not ".path". If not specified, this value defaults to a service
           that has the same name as the path unit, except for the suffix. (See above.) It is
           recommended that the unit name that is activated and the unit name of the path unit
           are named identical, except for the suffix.

       MakeDirectory=
           Takes a boolean argument. If true, the directories to watch are created before
           watching. This option is ignored for PathExists= settings. Defaults to false.

       DirectoryMode=
           If MakeDirectory= is enabled, use the mode specified here to create the directories in
           question. Takes an access mode in octal notation. Defaults to 0755.

       TriggerLimitIntervalSec=, TriggerLimitBurst=
           Configures a limit on how often this path unit may be activated within a specific time
           interval. The TriggerLimitIntervalSec= may be used to configure the length of the time
           interval in the usual time units "us", "ms", "s", "min", "h", ... and defaults to 2s.
           See systemd.time(7) for details on the various time units understood. The
           TriggerLimitBurst= setting takes a positive integer value and specifies the number of
           permitted activations per time interval, and defaults to 200. Set either to 0 to
           disable any form of trigger rate limiting. If the limit is hit, the unit is placed
           into a failure mode, and will not watch the paths anymore until restarted. Note that
           this limit is enforced before the service activation is enqueued.

       Check systemd.unit(5), systemd.exec(5), and systemd.kill(5) for more settings.

SEE ALSO

       Environment variables with details on the trigger will be set for triggered units. See the
       section "Environment Variables Set or Propagated by the Service Manager" in
       systemd.exec(5) for more details.

       systemd(1), systemctl(1), systemd.unit(5), systemd.service(5), inotify(7),
       systemd.directives(7)