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
12 udevadm trigger [options]
14 udevadm settle [options]
16 udevadm control command
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.
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31 --debug
32 Print debug messages to standard error.
33 --version
35 Print version number.
36 -h, --help
38 Print help text.
39 udevadm info [options] [devpath|file]
41 Queries the udev database for device information stored in the udev
42 database. It can also query the properties of a device from its sysfs
43 representation to help creating udev rules that match this device.
44 -q, --query=TYPE
46 Query the database for the specified type of device data. It needs
47 the --path or --name to identify the specified device. Valid TYPEs
48 are: name, symlink, path, property, all.
49 -p, --path=DEVPATH
51 The /sys path of the device to query, e.g. [/sys]/class/block/sda.
52 Note that this option usually is not very useful, since udev can
53 guess the type of the argument, so udevadm
54 --devpath=/class/block/sda is equivalent to udevadm
55 /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. Note that this option usually is not very useful, since
60 udev can guess the type of the argument, so udevadm --name=sda is
61 equivalent to udevadm /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.
75 -P, --export-prefix=NAME
77 Add a prefix to the key name of exported values.
78 -d, --device-id-of-file=FILE
80 Print major/minor numbers of the underlying device, where the file
81 lives on.
82 -e, --export-db
84 Export the content of the udev database.
85 -c, --cleanup-db
87 Cleanup the udev database.
88 -h, --help
90 Print help text.
91 In addition an optional positional argument can be used to specify a
93 device name or a sys path. It must start with /dev or /sys
94 respectively.
95 udevadm trigger [options] [devpath|file...]
97 Request device events from the kernel. Primarily used to replay events
98 at system coldplug time.
99 -v, --verbose
101 Print the list of devices which will be triggered.
102 -n, --dry-run
104 Do not actually trigger the event.
105 -t, --type=TYPE
107 Trigger a specific type of devices. Valid types are: devices,
108 subsystems. The default value is devices.
109 -c, --action=ACTION
111 Type of event to be triggered. The default value is change.
112 -s, --subsystem-match=SUBSYSTEM
114 Trigger events for devices which belong to a matching subsystem.
115 This option can be specified multiple times and supports shell
116 style pattern matching.
117 -S, --subsystem-nomatch=SUBSYSTEM
119 Do not trigger events for devices which belong to a matching
120 subsystem. This option can be specified multiple times and supports
121 shell style pattern matching.
122 -a, --attr-match=ATTRIBUTE=VALUE
124 Trigger events for devices with a matching sysfs attribute. If a
125 value is specified along with the attribute name, the content of
126 the attribute is matched against the given value using shell style
127 pattern matching. If no value is specified, the existence of the
128 sysfs attribute is checked. This option can be specified multiple
129 times.
130 -A, --attr-nomatch=ATTRIBUTE=VALUE
132 Do not trigger events for devices with a matching sysfs attribute.
133 If a value is specified along with the attribute name, the content
134 of the attribute is matched against the given value using shell
135 style pattern matching. If no value is specified, the existence of
136 the sysfs attribute is checked. This option can be specified
137 multiple times.
138 -p, --property-match=PROPERTY=VALUE
140 Trigger events for devices with a matching property value. This
141 option can be specified multiple times and supports shell style
142 pattern matching.
143 -g, --tag-match=PROPERTY
145 Trigger events for devices with a matching tag. This option can be
146 specified multiple times.
147 -y, --sysname-match=PATH
149 Trigger events for devices with a matching sys device path. This
150 option can be specified multiple times and supports shell style
151 pattern matching.
152 --name-match=NAME
154 Trigger events for devices with a matching device path. This
155 options can be specified multiple times.
156 -b, --parent-match=SYSPATH
158 Trigger events for all children of a given device.
159 -h, --help
161 Print help text.
162 In addition optional positional arguments can be used to specify device
164 names or sys paths. They must start with /dev or /sys respectively.
165 udevadm settle [options]
167 Watches the udev event queue, and exits if all current events are
168 handled.
169 -t, --timeout=SECONDS
171 Maximum number of seconds to wait for the event queue to become
172 empty. The default value is 120 seconds. A value of 0 will check if
173 the queue is empty and always return immediately.
174 -E, --exit-if-exists=FILE
176 Stop waiting if file exists.
177 -h, --help
179 Print help text.
180 udevadm control command
182 Modify the internal state of the running udev daemon.
183 -e, --exit
185 Signal and wait for systemd-udevd to exit.
186 -l, --log-priority=value
188 Set the internal log level of systemd-udevd. Valid values are the
189 numerical syslog priorities or their textual representations:
190 emerg, alert, crit, err, warning, notice, info, and debug.
191 -s, --stop-exec-queue
193 Signal systemd-udevd to stop executing new events. Incoming events
194 will be queued.
195 -S, --start-exec-queue
197 Signal systemd-udevd to enable the execution of events.
198 -R, --reload
200 Signal systemd-udevd to reload the rules files and other databases
201 like the kernel module index. Reloading rules and databases does
202 not apply any changes to already existing devices; the new
203 configuration will only be applied to new events.
204 -p, --property=KEY=value
206 Set a global property for all events.
207 -m, --children-max=value
209 Set the maximum number of events, systemd-udevd will handle at the
210 same time.
211 --timeout=seconds
213 The maximum number of seconds to wait for a reply from
214 systemd-udevd.
215 -h, --help
217 Print help text.
218 udevadm monitor [options]
220 Listens to the kernel uevents and events sent out by a udev rule and
221 prints the devpath of the event to the console. It can be used to
222 analyze the event timing, by comparing the timestamps of the kernel
223 uevent and the udev event.
224 -k, --kernel
226 Print the kernel uevents.
227 -u, --udev
229 Print the udev event after the rule processing.
230 -p, --property
232 Also print the properties of the event.
233 -s, --subsystem-match=string[/string]
235 Filter events by subsystem[/devtype]. Only udev events with a
236 matching subsystem value will pass.
237 -t, --tag-match=string
239 Filter events by property. Only udev events with a given tag
240 attached will pass.
241 -h, --help
243 Print help text.
244 udevadm test [options] [devpath]
246 Simulate a udev event run for the given device, and print debug output.
247 -a, --action=string
249 The action string.
250 -N, --resolve-names=early|late|never
252 Specify when udevadm should resolve names of users and groups. When
253 set to early (the default), names will be resolved when the rules
254 are parsed. When set to late, names will be resolved for every
255 event. When set to never, names will never be resolved and all
256 devices will be owned by root.
257 -h, --help
259 Print help text.
260 udevadm test-builtin [options] [command] [devpath]
262 Run a built-in command COMMAND for device DEVPATH, and print debug
263 output.
264 -h, --help
266 Print help text.
267
269 udev(7), systemd-udevd.service(8)
270systemd 219 UDEVADM(8)