systemd.path(5) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | AUTOMATIC DEPENDENCIES | OPTIONS | SEE ALSO | COLOPHON

SYSTEMD.PATH(5)               systemd.path               SYSTEMD.PATH(5)

NAME         top

       systemd.path - Path unit configuration

SYNOPSIS         top

       path.path

DESCRIPTION         top

       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         top

   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         top

       Path files must include a [Path] section, which carries
       information about the path(s) 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 similar, 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.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2021-04-01.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-04-01.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 248                                              SYSTEMD.PATH(5)

Pages that refer to this page: systemd(1)systemd.unit(5)daemon(7)systemd.directives(7)systemd.index(7)systemd.special(7)systemd.syntax(7)