UDEVADM(8)

NAME

udevadm - udev management tool

SYNOPSIS

udevadm [--debug] [--version] [--help]

udevadm info options

udevadm trigger [options]

udevadm settle [options]

udevadm control command

udevadm monitor [options]

udevadm test [options] devpath

DESCRIPTION

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.

OPTIONS

--debug

Print debug messages to stderr.

--version

Print version number.

--help

Print help text.

udevadm info options

Queries 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=type

Query 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=devpath

The devpath of the device to query.

--name=file

The name of the device node or a symlink to query

--root

The udev root directory: /dev. If used in conjunction with a name or symlink query, the query returns the absolute path including the root directory.

--attribute-walk

Print 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.

--device-id-of-file=file

Print major/minor numbers of the underlying device, where the file lives on.

--export-db

Export the content of the udev database.

--version

Print version.

--help

Print help text.

udevadm trigger [options]

Request device events from the kernel. Primarily used to replay events at system coldplug time.

--verbose

Print the list of devices which will be triggered.

--dry-run

Do not actually trigger the event.

--type=type

Trigger a specific type of devices. Valid types are: devices, subsystems, failed. The default value is devices.

--action=action

Type of event to be triggered. The default value is change.

--subsystem-match=subsystem

Trigger events for devices which belong to a matching subsystem.
This option can be specified multiple times and supports shell
style pattern matching.

--subsystem-nomatch=subsystem

Do 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=value

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.

--attr-nomatch=attribute=value

Do 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=value

Trigger events for devices with a matching property value. This
option can be specified multiple times and supports shell style
pattern matching.

--tag-match=property

Trigger events for devices with a matching tag. This option can be specified multiple times.

--sysname-match=name

Trigger events for devices with a matching sys device name. This
option can be specified multiple times and supports shell style
pattern matching.

udevadm settle [options]

Watches the udev event queue, and exits if all current events are
handled.

--timeout=seconds

Maximum number of seconds to wait for the event queue to become
empty. The default value is 180 seconds. A value of 0 will check if the queue is empty and always return immediately.

--seq-start=seqnum

Wait only for events after the given sequence number.

--seq-end=seqnum

Wait only for events before the given sequence number.

--exit-if-exists=file

Stop waiting if file exists.

--quiet

Do not print any output, like the remaining queue entries when
reaching the timeout.

--help

Print help text.

udevadm control command

Modify the internal state of the running udev daemon.

--log-priority=value

Set the internal log level of udevd. Valid values are the numerical syslog priorities or their textual representations: err, info and debug.

--stop-exec-queue

Signal udevd to stop executing new events. Incoming events will be queued.

--start-exec-queue

Signal udevd to enable the execution of events.

--reload-rules

Signal 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=value

Set a global property for all events.

--children-max=value

Set the maximum number of events, udevd will handle at the same
time.

--help

Print help text.

udevadm monitor [options]

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.

--kernel

Print the kernel uevents.

--udev

Print the udev event after the rule processing.

--property

Also 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=string

Filter events by property. Only udev events with a given tag
attached will pass.

--help

Print help text.

udevadm test [options] devpath

Simulate a udev event run for the given device, and print debug output.

--action=string

The action string.

--subsystem=string

The subsystem string.

--help

Print help text.

AUTHOR

Written by Kay Sievers kay.sievers@vrfy.org.

SEE ALSO

udev(7) udevd(8)

udev 08/11/2010 UDEVADM(8)