UDEVADM(8)

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 kernel 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-nomatchattribute=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.

  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 var=value
    Set global variable.

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

--max_childs_running
    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)