1SYSTEMD.DEVICE(5)               systemd.device               SYSTEMD.DEVICE(5)
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NAME

6       systemd.device - Device unit configuration
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SYNOPSIS

9       device.device
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DESCRIPTION

12       A unit configuration file whose name ends in ".device" encodes
13       information about a device unit as exposed in the sysfs/udev(7) device
14       tree.
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16       This unit type has no specific options. See systemd.unit(5) for the
17       common options of all unit configuration files. The common
18       configuration items are configured in the generic "[Unit]" and
19       "[Install]" sections. A separate "[Device]" section does not exist,
20       since no device-specific options may be configured.
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22       systemd will dynamically create device units for all kernel devices
23       that are marked with the "systemd" udev tag (by default all block and
24       network devices, and a few others). This may be used to define
25       dependencies between devices and other units. To tag a udev device, use
26       "TAG+="systemd"" in the udev rules file, see udev(7) for details.
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28       Device units are named after the /sys and /dev paths they control.
29       Example: the device /dev/sda5 is exposed in systemd as dev-sda5.device.
30       For details about the escaping logic used to convert a file system path
31       to a unit name see systemd.unit(5).
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THE UDEV DATABASE

34       The settings of device units may either be configured via unit files,
35       or directly from the udev database (which is recommended). The
36       following udev device properties are understood by systemd:
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38       SYSTEMD_WANTS=
39           Adds dependencies of type Wants from the device unit to all listed
40           units. This settings may be used to activate arbitrary units when a
41           specific device becomes available.
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43           Note that this and the other tags are not taken into account unless
44           the device is tagged with the "systemd" string in the udev
45           database, because otherwise the device is not exposed as a systemd
46           unit (see above).
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48           Note that systemd will only act on Wants dependencies when a device
49           first becomes active. It will not act on them if they are added to
50           devices that are already active. Use SYSTEMD_READY= (see below) to
51           influence on which udev event to trigger the dependencies.
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53       SYSTEMD_ALIAS=
54           Adds an additional alias name to the device unit. This must be an
55           absolute path that is automatically transformed into a unit name.
56           (See above.)
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58       SYSTEMD_READY=
59           If set to 0, systemd will consider this device unplugged even if it
60           shows up in the udev tree. If this property is unset or set to 1,
61           the device will be considered plugged if it is visible in the udev
62           tree. This property has no influence on the behavior when a device
63           disappears from the udev tree.
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65           This option is useful to support devices that initially show up in
66           an uninitialized state in the tree, and for which a "changed" event
67           is generated the moment they are fully set up. Note that
68           SYSTEMD_WANTS= (see above) is not acted on as long as
69           SYSTEMD_READY=0 is set for a device.
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71       ID_MODEL_FROM_DATABASE=, ID_MODEL=
72           If set, this property is used as description string for the device
73           unit.
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SEE ALSO

76       systemd(1), systemctl(1), systemd.unit(5), udev(7),
77       systemd.directives(7)
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81systemd 219                                                  SYSTEMD.DEVICE(5)
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