1SYSTEMD.PATH(5)                  systemd.path                  SYSTEMD.PATH(5)
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NAME

6       systemd.path - Path unit configuration
7

SYNOPSIS

9       path.path
10

DESCRIPTION

12       A unit configuration file whose name ends in ".path" encodes
13       information about a path monitored by systemd, for path-based
14       activation.
15
16       This man page lists the configuration options specific to this unit
17       type. See systemd.unit(5) for the common options of all unit
18       configuration files. The common configuration items are configured in
19       the generic [Unit] and [Install] sections. The path specific
20       configuration options are configured in the [Path] section.
21
22       For each path file, a matching unit file must exist, describing the
23       unit to activate when the path changes. By default, a service by the
24       same name as the path (except for the suffix) is activated. Example: a
25       path file foo.path activates a matching service foo.service. The unit
26       to activate may be controlled by Unit= (see below).
27
28       Internally, path units use the inotify(7) API to monitor file systems.
29       Due to that, it suffers by the same limitations as inotify, and for
30       example cannot be used to monitor files or directories changed by other
31       machines on remote NFS file systems.
32
33       When a service unit triggered by a path unit terminates (regardless
34       whether it exited successfully or failed), monitored paths are checked
35       immediately again, and the service accordingly restarted instantly. As
36       protection against busy looping in this trigger/start cycle, a start
37       rate limit is enforced on the service unit, see StartLimitIntervalSec=
38       and StartLimitBurst= in systemd.unit(5). Unlike other service failures,
39       the error condition that the start rate limit is hit is propagated from
40       the service unit to the path unit and causes the path unit to fail as
41       well, thus ending the loop.
42

AUTOMATIC DEPENDENCIES

44   Implicit Dependencies
45       The following dependencies are implicitly added:
46
47       •   If a path unit is beneath another mount unit in the file system
48           hierarchy, both a requirement and an ordering dependency between
49           both units are created automatically.
50
51       •   An implicit Before= dependency is added between a path unit and the
52           unit it is supposed to activate.
53
54   Default Dependencies
55       The following dependencies are added unless DefaultDependencies=no is
56       set:
57
58       •   Path units will automatically have dependencies of type Before= on
59           paths.target, dependencies of type After= and Requires= on
60           sysinit.target, and have dependencies of type Conflicts= and
61           Before= on shutdown.target. These ensure that path units are
62           terminated cleanly prior to system shutdown. Only path units
63           involved with early boot or late system shutdown should disable
64           DefaultDependencies= option.
65

OPTIONS

67       Path unit files may include [Unit] and [Install] sections, which are
68       described in systemd.unit(5).
69
70       Path unit files must include a [Path] section, which carries
71       information about the path or paths it monitors. The options specific
72       to the [Path] section of path units are the following:
73
74       PathExists=, PathExistsGlob=, PathChanged=, PathModified=,
75       DirectoryNotEmpty=
76           Defines paths to monitor for certain changes: PathExists= may be
77           used to watch the mere existence of a file or directory. If the
78           file specified exists, the configured unit is activated.
79           PathExistsGlob= works similarly, but checks for the existence of at
80           least one file matching the globbing pattern specified.
81           PathChanged= may be used to watch a file or directory and activate
82           the configured unit whenever it changes. It is not activated on
83           every write to the watched file but it is activated if the file
84           which was open for writing gets closed.  PathModified= is similar,
85           but additionally it is activated also on simple writes to the
86           watched file.  DirectoryNotEmpty= may be used to watch a directory
87           and activate the configured unit whenever it contains at least one
88           file.
89
90           The arguments of these directives must be absolute file system
91           paths.
92
93           Multiple directives may be combined, of the same and of different
94           types, to watch multiple paths. If the empty string is assigned to
95           any of these options, the list of paths to watch is reset, and any
96           prior assignments of these options will not have any effect.
97
98           If a path already exists (in case of PathExists= and
99           PathExistsGlob=) or a directory already is not empty (in case of
100           DirectoryNotEmpty=) at the time the path unit is activated, then
101           the configured unit is immediately activated as well. Something
102           similar does not apply to PathChanged= and PathModified=.
103
104           If the path itself or any of the containing directories are not
105           accessible, systemd will watch for permission changes and notice
106           that conditions are satisfied when permissions allow that.
107
108       Unit=
109           The unit to activate when any of the configured paths changes. The
110           argument is a unit name, whose suffix is not ".path". If not
111           specified, this value defaults to a service that has the same name
112           as the path unit, except for the suffix. (See above.) It is
113           recommended that the unit name that is activated and the unit name
114           of the path unit are named identical, except for the suffix.
115
116       MakeDirectory=
117           Takes a boolean argument. If true, the directories to watch are
118           created before watching. This option is ignored for PathExists=
119           settings. Defaults to false.
120
121       DirectoryMode=
122           If MakeDirectory= is enabled, use the mode specified here to create
123           the directories in question. Takes an access mode in octal
124           notation. Defaults to 0755.
125
126       TriggerLimitIntervalSec=, TriggerLimitBurst=
127           Configures a limit on how often this path unit may be activated
128           within a specific time interval. The TriggerLimitIntervalSec= may
129           be used to configure the length of the time interval in the usual
130           time units "us", "ms", "s", "min", "h", ... and defaults to 2s. See
131           systemd.time(7) for details on the various time units understood.
132           The TriggerLimitBurst= setting takes a positive integer value and
133           specifies the number of permitted activations per time interval,
134           and defaults to 200. Set either to 0 to disable any form of trigger
135           rate limiting. If the limit is hit, the unit is placed into a
136           failure mode, and will not watch the paths anymore until restarted.
137           Note that this limit is enforced before the service activation is
138           enqueued.
139
140       Check systemd.unit(5), systemd.exec(5), and systemd.kill(5) for more
141       settings.
142

SEE ALSO

144       Environment variables with details on the trigger will be set for
145       triggered units. See the section "Environment Variables Set or
146       Propagated by the Service Manager" in systemd.exec(5) for more details.
147
148       systemd(1), systemctl(1), systemd.unit(5), systemd.service(5),
149       inotify(7), systemd.directives(7)
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153systemd 253                                                    SYSTEMD.PATH(5)
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