udevadm — udev management tool
udevadm [--debug] [--version] [--help]
udevadm info options
udevadm trigger [options]
udevadm settle [options]
udevadm control command
udevadm monitor [options]
udevadm test [options] devpath
udevadm test-builtin [options] command devpath
udevadm expects a command and command specific options. It controls the runtime behavior of udev, requests kernel events, manages the event queue, and provides simple debugging mechanisms.
--debugPrint debug messages to stderr.
--versionPrint version number.
--helpPrint help text.
optionsQueries the udev database for device information stored in the udev database. It can also query the properties of a device from its sysfs representation to help creating udev rules that match this device.
--query=typeQuery the database for specified type of device data. It needs the
--path or --name to identify the specified
device. Valid queries are:
name, symlink, path,
property, all.
--path=devpathThe devpath of the device to query.
--name=fileThe name of the device node or a symlink to query
--rootThe udev root directory: /dev. If used in conjunction
with a name or symlink query, the
query returns the absolute path including the root directory.
--runThe udev runtime directory: /run/udev.
--attribute-walkPrint all sysfs properties of the specified device that can be used in udev rules to match the specified device. It prints all devices along the chain, up to the root of sysfs that can be used in udev rules.
--exportPrint output as key/value pairs. Values are enclosed in single quotes.
--export-prefix=nameAdd a prefix to the key name of exported values.
--device-id-of-file=filePrint major/minor numbers of the underlying device, where the file lives on.
--export-dbExport the content of the udev database.
--cleanup-dbCleanup the udev database.
--versionPrint version.
--helpPrint help text.
Request device events from the kernel. Primarily used to replay events at system coldplug time.
--verbosePrint the list of devices which will be triggered.
--dry-runDo not actually trigger the event.
--type=typeTrigger a specific type of devices. Valid types are: devices, subsystems. The default value is devices.
--action=actionType of event to be triggered. The default value is change.
--subsystem-match=subsystemTrigger events for devices which belong to a matching subsystem. This option can be specified multiple times and supports shell style pattern matching.
--subsystem-nomatch=subsystemDo not trigger events for devices which belong to a matching subsystem. This option can be specified multiple times and supports shell style pattern matching.
--attr-match=attribute=valueTrigger events for devices with a matching sysfs attribute. If a value is specified along with the attribute name, the content of the attribute is matched against the given value using shell style pattern matching. If no value is specified, the existence of the sysfs attribute is checked. This option can be specified multiple times.
--attr-nomatch=attribute=valueDo not trigger events for devices with a matching sysfs attribute. If a value is specified along with the attribute name, the content of the attribute is matched against the given value using shell style pattern matching. If no value is specified, the existence of the sysfs attribute is checked. This option can be specified multiple times.
--property-match=property=valueTrigger events for devices with a matching property value. This option can be specified multiple times and supports shell style pattern matching.
--tag-match=propertyTrigger events for devices with a matching tag. This option can be specified multiple times.
--sysname-match=nameTrigger events for devices with a matching sys device name. This option can be specified multiple times and supports shell style pattern matching.
--parent-match=syspathTrigger events for all children of a given device.
Watches the udev event queue, and exits if all current events are handled.
--timeout=secondsMaximum number of seconds to wait for the event queue to become empty. The default value is 120 seconds. A value of 0 will check if the queue is empty and always return immediately.
--seq-start=seqnumWait only for events after the given sequence number.
--seq-end=seqnumWait only for events before the given sequence number.
--exit-if-exists=fileStop waiting if file exists.
--quietDo not print any output, like the remaining queue entries when reaching the timeout.
--helpPrint help text.
commandModify the internal state of the running udev daemon.
--exitSignal and wait for udevd to exit.
--log-priority=valueSet the internal log level of udevd. Valid values are the numerical
syslog priorities or their textual representations: err,
info and debug.
--stop-exec-queueSignal udevd to stop executing new events. Incoming events will be queued.
--start-exec-queueSignal udevd to enable the execution of events.
--reload-rulesSignal udevd to reload the rules files. The udev daemon detects changes automatically, this option is usually not needed. Reloading rules does not apply any changes to already existing devices.
--property=KEY=valueSet a global property for all events.
--children-max=valueSet the maximum number of events, udevd will handle at the same time.
--timeout=secondsThe maximum number seonds to wait for a reply from udevd.
--helpPrint help text.
Listens to the kernel uevents and events sent out by a udev rule and prints the devpath of the event to the console. It can be used to analyze the event timing, by comparing the timestamps of the kernel uevent and the udev event.
--kernelPrint the kernel uevents.
--udevPrint the udev event after the rule processing.
--propertyAlso print the properties of the event.
--subsystem-match=string[/string]Filter events by subsystem[/devtype]. Only udev events with a matching subsystem value will pass.
--tag-match=stringFilter events by property. Only udev events with a given tag attached will pass.
--helpPrint help text.