systemd.path — Path unit configuration
path.path
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.
If a path unit is beneath another mount point in the file system hierarchy, a dependency between both units is created automatically.
Unless DefaultDependencies=false
is used, path units will implicitly 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 this option.
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.