1UDEVADM(8) udevadm UDEVADM(8)
2
6 udevadm - udev management tool
7
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|unit...]
39 Query the udev database for device information.
40 Positional arguments should be used to specify one or more devices.
42 Each one may be a device name (in which case it must start with /dev/),
43 a sys path (in which case it must start with /sys/), or a systemd
44 device unit name (in which case it must end with ".device", see
45 systemd.device(5)).
46 -q, --query=TYPE
48 Query the database for the specified type of device data. Valid
49 TYPEs are: name, symlink, path, property, all.
50 -p, --path=DEVPATH
52 The /sys path of the device to query, e.g. [/sys]/class/block/sda.
53 This option is an alternative to the positional argument with a
54 /sys/ prefix. udevadm info --path=/class/block/sda is equivalent
55 to udevadm info /sys/class/block/sda.
56 -n, --name=FILE
58 The name of the device node or a symlink to query, e.g.
59 [/dev]/sda. This option is an alternative to the positional
60 argument with a /dev/ prefix. udevadm info --name=sda is
61 equivalent to udevadm info /dev/sda.
62 -r, --root
64 Print absolute paths in name or symlink query.
65 -a, --attribute-walk
67 Print all sysfs properties of the specified device that can be used
68 in udev rules to match the specified device. It prints all devices
69 along the chain, up to the root of sysfs that can be used in udev
70 rules.
71 -x, --export
73 Print output as key/value pairs. Values are enclosed in single
74 quotes. This takes effects only when --query=property or
75 --device-id-of-file=FILE is specified.
76 -P, --export-prefix=NAME
78 Add a prefix to the key name of exported values. This implies
79 --export.
80 -d, --device-id-of-file=FILE
82 Print major/minor numbers of the underlying device, where the file
83 lives on. If this is specified, all positional arguments are
84 ignored.
85 -e, --export-db
87 Export the content of the udev database.
88 -c, --cleanup-db
90 Cleanup the udev database.
91 -w[SECONDS], --wait-for-initialization[=SECONDS]
93 Wait for device to be initialized. If argument SECONDS is not
94 specified, the default is to wait forever.
95 -h, --help
97 Print a short help text and exit.
98 udevadm trigger [options] [devpath|file|unit]
100 Request device events from the kernel. Primarily used to replay events
101 at system coldplug time.
102 Takes device specifications as positional arguments. See the
104 description of info above.
105 -v, --verbose
107 Print the list of devices which will be triggered.
108 -n, --dry-run
110 Do not actually trigger the event.
111 -t, --type=TYPE
113 Trigger a specific type of devices. Valid types are: devices,
114 subsystems. The default value is devices.
115 -c, --action=ACTION
117 Type of event to be triggered. Possible actions are "add",
118 "remove", "change", "move", "online", "offline", "bind", and
119 "unbind". Also, the special value "help" can be used to list the
120 possible actions. The default value is "change".
121 -s, --subsystem-match=SUBSYSTEM
123 Trigger events for devices which belong to a matching subsystem.
124 This option supports shell style pattern matching. When this option
125 is specified more than once, then each matching result is ORed,
126 that is, all the devices in each subsystem are triggered.
127 -S, --subsystem-nomatch=SUBSYSTEM
129 Do not trigger events for devices which belong to a matching
130 subsystem. This option supports shell style pattern matching. When
131 this option is specified more than once, then each matching result
132 is ANDed, that is, devices which do not match all specified
133 subsystems are triggered.
134 -a, --attr-match=ATTRIBUTE=VALUE
136 Trigger events for devices with a matching sysfs attribute. If a
137 value is specified along with the attribute name, the content of
138 the attribute is matched against the given value using shell style
139 pattern matching. If no value is specified, the existence of the
140 sysfs attribute is checked. When this option is specified multiple
141 times, then each matching result is ANDed, that is, only devices
142 which have all specified attributes are triggered.
143 -A, --attr-nomatch=ATTRIBUTE=VALUE
145 Do not trigger events for devices with a matching sysfs attribute.
146 If a value is specified along with the attribute name, the content
147 of the attribute is matched against the given value using shell
148 style pattern matching. If no value is specified, the existence of
149 the sysfs attribute is checked. When this option is specified
150 multiple times, then each matching result is ANDed, that is, only
151 devices which have none of the specified attributes are triggered.
152 -p, --property-match=PROPERTY=VALUE
154 Trigger events for devices with a matching property value. This
155 option supports shell style pattern matching. When this option is
156 specified more than once, then each matching result is ORed, that
157 is, devices which have one of the specified properties are
158 triggered.
159 -g, --tag-match=PROPERTY
161 Trigger events for devices with a matching tag. When this option is
162 specified multiple times, then each matching result is ANDed, that
163 is, devices which have all specified tags are triggered.
164 -y, --sysname-match=NAME
166 Trigger events for devices for which the last component (i.e. the
167 filename) of the /sys path matches the specified PATH. This option
168 supports shell style pattern matching. When this option is
169 specified more than once, then each matching result is ORed, that
170 is, all devices which have any of the specified NAME are triggered.
171 --name-match=NAME
173 Trigger events for devices with a matching device path. When this
174 option is specified more than once, then each matching result is
175 ORed, that is, all specified devices are triggered.
176 -b, --parent-match=SYSPATH
178 Trigger events for all children of a given device. When this option
179 is specified more than once, then each matching result is ORed,
180 that is, all children of each specified device are triggered.
181 -w, --settle
183 Apart from triggering events, also waits for those events to
184 finish. Note that this is different from calling udevadm settle.
185 udevadm settle waits for all events to finish. This option only
186 waits for events triggered by the same command to finish.
187 --wait-daemon[=SECONDS]
189 Before triggering uevents, wait for systemd-udevd daemon to be
190 initialized. Optionally takes timeout value. Default timeout is 5
191 seconds. This is equivalent to invoke invoking udevadm control
192 --ping before udevadm trigger.
193 -h, --help
195 Print a short help text and exit.
196 In addition, optional positional arguments can be used to specify
198 device names or sys paths. They must start with /dev or /sys
199 respectively.
200 udevadm settle [options]
202 Watches the udev event queue, and exits if all current events are
203 handled.
204 -t, --timeout=SECONDS
206 Maximum number of seconds to wait for the event queue to become
207 empty. The default value is 120 seconds. A value of 0 will check if
208 the queue is empty and always return immediately.
209 -E, --exit-if-exists=FILE
211 Stop waiting if file exists.
212 -h, --help
214 Print a short help text and exit.
215 See systemd-udev-settle.service(8) for more information.
217 udevadm control option
219 Modify the internal state of the running udev daemon.
220 -e, --exit
222 Signal and wait for systemd-udevd to exit. No option except for
223 --timeout can be specified after this option. Note that
224 systemd-udevd.service contains Restart=always and so as a result,
225 this option restarts systemd-udevd. If you want to stop
226 systemd-udevd.service, please use the following:
227 systemctl stop systemd-udevd-control.socket systemd-udevd-kernel.socket systemd-udevd.service
229 -l, --log-priority=value
232 Set the internal log level of systemd-udevd. Valid values are the
233 numerical syslog priorities or their textual representations:
234 emerg, alert, crit, err, warning, notice, info, and debug.
235 -s, --stop-exec-queue
237 Signal systemd-udevd to stop executing new events. Incoming events
238 will be queued.
239 -S, --start-exec-queue
241 Signal systemd-udevd to enable the execution of events.
242 -R, --reload
244 Signal systemd-udevd to reload the rules files and other databases
245 like the kernel module index. Reloading rules and databases does
246 not apply any changes to already existing devices; the new
247 configuration will only be applied to new events.
248 -p, --property=KEY=value
250 Set a global property for all events.
251 -m, --children-max=value
253 Set the maximum number of events, systemd-udevd will handle at the
254 same time.
255 --ping
257 Send a ping message to systemd-udevd and wait for the reply. This
258 may be useful to check that systemd-udevd daemon is running.
259 -t, --timeout=seconds
261 The maximum number of seconds to wait for a reply from
262 systemd-udevd.
263 -h, --help
265 Print a short help text and exit.
266 udevadm monitor [options]
268 Listens to the kernel uevents and events sent out by a udev rule and
269 prints the devpath of the event to the console. It can be used to
270 analyze the event timing, by comparing the timestamps of the kernel
271 uevent and the udev event.
272 -k, --kernel
274 Print the kernel uevents.
275 -u, --udev
277 Print the udev event after the rule processing.
278 -p, --property
280 Also print the properties of the event.
281 -s, --subsystem-match=string[/string]
283 Filter kernel uevents and udev events by subsystem[/devtype]. Only
284 events with a matching subsystem value will pass. When this option
285 is specified more than once, then each matching result is ORed,
286 that is, all devices in the specified subsystems are monitored.
287 -t, --tag-match=string
289 Filter udev events by tag. Only udev events with a given tag
290 attached will pass. When this option is specified more than once,
291 then each matching result is ORed, that is, devices which have one
292 of the specified tags are monitored.
293 -h, --help
295 Print a short help text and exit.
296 udevadm test [options] [devpath]
298 Simulate a udev event run for the given device, and print debug output.
299 -a, --action=ACTION
301 Type of event to be simulated. Possible actions are "add",
302 "remove", "change", "move", "online", "offline", "bind", and
303 "unbind". Also, the special value "help" can be used to list the
304 possible actions. The default value is "add".
305 -N, --resolve-names=early|late|never
307 Specify when udevadm should resolve names of users and groups. When
308 set to early (the default), names will be resolved when the rules
309 are parsed. When set to late, names will be resolved for every
310 event. When set to never, names will never be resolved and all
311 devices will be owned by root.
312 -h, --help
314 Print a short help text and exit.
315 udevadm test-builtin [options] [command] [devpath]
317 Run a built-in command COMMAND for device DEVPATH, and print debug
318 output.
319 -h, --help
321 Print a short help text and exit.
322
324 udev(7), systemd-udevd.service(8)
325systemd 245 UDEVADM(8)