UDEVADM

NAME

udevadm - udev management tool

SYNOPSIS

	udevadm info [options]
	udevadm trigger [options]
	udevadm settle [options]
	udevadm control [options] instruction
	udevadm monitor [options]
	udevadm test [options] devpath
	udevadm version
	udevadm help

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

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, env, 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 uevents, usually used to replay events at system coldplug.

−−verbose

Print the list of devices which will be triggered.

−−dry−run

Do not actually trigger the event.

−−retry−failed

Trigger only the events which are failed during a previous run.

−−action=action

Type of event to be triggered. The default value is "add".

−−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.

−−socket=path

Pass the synthesized events to the specified socket, instead of triggering a global kernel event. All available event values will be send in the same format the kernel sends an uevent, or RUN+="socket:path" sends a message. If the first character of the specified path is an @ character, an abstract namespace socket is used, instead of an existing socket file.

−−env=KEY=value

Pass an additional environemt key to the event. This works only with the −−socket option.

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.

−−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 from the config.

−−env=KEY=value

Set global variable.

−−max_childs=value

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

−−max_childs_running=value

Set the maximum number of events, which are allowed to run 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.

−−environment

Print the complete environment for all events. Can be used to compare the kernel supplied and the udev added environment values.

−−kernel

Print the kernel uevents.

−−udev

Print the udev event after the rule processing.

−−help

Print help text.

udevadm test [options] devpath
Simulate a udev event run for the given device, and print out debug output. Unless forced to, no device node or symlink will be created.

−−action=string

The action string.

−−subsystem=string

The subsystem string.

−−force

Force the creation of a device node or symlink. Usually the test run prints only debug output.

−−help

Print help text.

udevadm version
Print version number.

udevadm help
Print help text.

AUTHOR

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

SEE ALSO

udev(7) udevd(8)