1UDEVADM(8) udevadm UDEVADM(8)
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6 udevadm - udev management tool
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9 udevadm [--debug] [--version] [--help]
10 udevadm info [options] [devpath]
12 udevadm trigger [options] [devpath]
14 udevadm settle [options]
16 udevadm control option
18 udevadm monitor [options]
20 udevadm test [options] devpath
22 udevadm test-builtin [options] command devpath
24
26 udevadm expects a command and command specific options. It controls the
27 runtime behavior of systemd-udevd, requests kernel events, manages the
28 event queue, and provides simple debugging mechanisms.
29
31 -d, --debug
32 Print debug messages to standard error. This option is implied in
33 udevadm test and udevadm test-builtin commands.
34 -h, --help
36 Print a short help text and exit.
37 udevadm info [options] [devpath|file]
39 Queries the udev database for device information stored in the udev
40 database. It can also query the properties of a device from its sysfs
41 representation to help creating udev rules that match this device.
42 -q, --query=TYPE
44 Query the database for the specified type of device data. It needs
45 the --path or --name to identify the specified device. Valid TYPEs
46 are: name, symlink, path, property, all.
47 -p, --path=DEVPATH
49 The /sys path of the device to query, e.g. [/sys]/class/block/sda.
50 Note that this option usually is not very useful, since udev can
51 guess the type of the argument, so udevadm info
52 --path=/class/block/sda is equivalent to udevadm info
53 /sys/class/block/sda.
54 -n, --name=FILE
56 The name of the device node or a symlink to query, e.g.
57 [/dev]/sda. Note that this option usually is not very useful, since
58 udev can guess the type of the argument, so udevadm info --name=sda
59 is equivalent to udevadm info /dev/sda.
60 -r, --root
62 Print absolute paths in name or symlink query.
63 -a, --attribute-walk
65 Print all sysfs properties of the specified device that can be used
66 in udev rules to match the specified device. It prints all devices
67 along the chain, up to the root of sysfs that can be used in udev
68 rules.
69 -x, --export
71 Print output as key/value pairs. Values are enclosed in single
72 quotes.
73 -P, --export-prefix=NAME
75 Add a prefix to the key name of exported values.
76 -d, --device-id-of-file=FILE
78 Print major/minor numbers of the underlying device, where the file
79 lives on.
80 -e, --export-db
82 Export the content of the udev database.
83 -c, --cleanup-db
85 Cleanup the udev database.
86 -h, --help
88 Print a short help text and exit.
89 In addition, an optional positional argument can be used to specify a
91 device name or a sys path. It must start with /dev or /sys
92 respectively.
93 udevadm trigger [options] [devpath|file...]
95 Request device events from the kernel. Primarily used to replay events
96 at system coldplug time.
97 -v, --verbose
99 Print the list of devices which will be triggered.
100 -n, --dry-run
102 Do not actually trigger the event.
103 -t, --type=TYPE
105 Trigger a specific type of devices. Valid types are: devices,
106 subsystems. The default value is devices.
107 -c, --action=ACTION
109 Type of event to be triggered. The default value is change.
110 -s, --subsystem-match=SUBSYSTEM
112 Trigger events for devices which belong to a matching subsystem.
113 This option can be specified multiple times and supports shell
114 style pattern matching.
115 -S, --subsystem-nomatch=SUBSYSTEM
117 Do not trigger events for devices which belong to a matching
118 subsystem. This option can be specified multiple times and supports
119 shell style pattern matching.
120 -a, --attr-match=ATTRIBUTE=VALUE
122 Trigger events for devices with a matching sysfs attribute. If a
123 value is specified along with the attribute name, the content of
124 the attribute is matched against the given value using shell style
125 pattern matching. If no value is specified, the existence of the
126 sysfs attribute is checked. This option can be specified multiple
127 times.
128 -A, --attr-nomatch=ATTRIBUTE=VALUE
130 Do not trigger events for devices with a matching sysfs attribute.
131 If a value is specified along with the attribute name, the content
132 of the attribute is matched against the given value using shell
133 style pattern matching. If no value is specified, the existence of
134 the sysfs attribute is checked. This option can be specified
135 multiple times.
136 -p, --property-match=PROPERTY=VALUE
138 Trigger events for devices with a matching property value. This
139 option can be specified multiple times and supports shell style
140 pattern matching.
141 -g, --tag-match=PROPERTY
143 Trigger events for devices with a matching tag. This option can be
144 specified multiple times.
145 -y, --sysname-match=PATH
147 Trigger events for devices for which the last component (i.e. the
148 filename) of the /sys path matches the specified PATH. This option
149 can be specified multiple times and also supports shell style
150 pattern matching.
151 --name-match=NAME
153 Trigger events for devices with a matching device path. This option
154 can be specified multiple times.
155 -b, --parent-match=SYSPATH
157 Trigger events for all children of a given device.
158 -w, --settle
160 Apart from triggering events, also waits for those events to
161 finish. Note that this is different from calling udevadm settle.
162 udevadm settle waits for all events to finish. This option only
163 waits for events triggered by the same command to finish.
164 -h, --help
166 Print a short help text and exit.
167 In addition, optional positional arguments can be used to specify
169 device names or sys paths. They must start with /dev or /sys
170 respectively.
171 udevadm settle [options]
173 Watches the udev event queue, and exits if all current events are
174 handled.
175 -t, --timeout=SECONDS
177 Maximum number of seconds to wait for the event queue to become
178 empty. The default value is 120 seconds. A value of 0 will check if
179 the queue is empty and always return immediately.
180 -E, --exit-if-exists=FILE
182 Stop waiting if file exists.
183 -h, --help
185 Print a short help text and exit.
186 udevadm control option
188 Modify the internal state of the running udev daemon.
189 -e, --exit
191 Signal and wait for systemd-udevd to exit.
192 -l, --log-priority=value
194 Set the internal log level of systemd-udevd. Valid values are the
195 numerical syslog priorities or their textual representations:
196 emerg, alert, crit, err, warning, notice, info, and debug.
197 -s, --stop-exec-queue
199 Signal systemd-udevd to stop executing new events. Incoming events
200 will be queued.
201 -S, --start-exec-queue
203 Signal systemd-udevd to enable the execution of events.
204 -R, --reload
206 Signal systemd-udevd to reload the rules files and other databases
207 like the kernel module index. Reloading rules and databases does
208 not apply any changes to already existing devices; the new
209 configuration will only be applied to new events.
210 -p, --property=KEY=value
212 Set a global property for all events.
213 -m, --children-max=value
215 Set the maximum number of events, systemd-udevd will handle at the
216 same time.
217 -t, --timeout=seconds
219 The maximum number of seconds to wait for a reply from
220 systemd-udevd.
221 -h, --help
223 Print a short help text and exit.
224 udevadm monitor [options]
226 Listens to the kernel uevents and events sent out by a udev rule and
227 prints the devpath of the event to the console. It can be used to
228 analyze the event timing, by comparing the timestamps of the kernel
229 uevent and the udev event.
230 -k, --kernel
232 Print the kernel uevents.
233 -u, --udev
235 Print the udev event after the rule processing.
236 -p, --property
238 Also print the properties of the event.
239 -s, --subsystem-match=string[/string]
241 Filter kernel uevents and udev events by subsystem[/devtype]. Only
242 events with a matching subsystem value will pass.
243 -t, --tag-match=string
245 Filter udev events by tag. Only udev events with a given tag
246 attached will pass.
247 -h, --help
249 Print a short help text and exit.
250 udevadm test [options] [devpath]
252 Simulate a udev event run for the given device, and print debug output.
253 -a, --action=string
255 The action string.
256 -N, --resolve-names=early|late|never
258 Specify when udevadm should resolve names of users and groups. When
259 set to early (the default), names will be resolved when the rules
260 are parsed. When set to late, names will be resolved for every
261 event. When set to never, names will never be resolved and all
262 devices will be owned by root.
263 -h, --help
265 Print a short help text and exit.
266 udevadm test-builtin [options] [command] [devpath]
268 Run a built-in command COMMAND for device DEVPATH, and print debug
269 output.
270 -h, --help
272 Print a short help text and exit.
273
275 udev(7), systemd-udevd.service(8)
276systemd 239 UDEVADM(8)