Provided by: udev_204-5ubuntu20.31_amd64 
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 hwdb [options]
udevadm test [options] devpath
udevadm test-builtin [options] command 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
Print absolute paths in name or symlink query.
--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.
--export
Print output as key/value pairs. Values are enclosed in single quotes.
--export-prefix=name
Add a prefix to the key name of exported values.
--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.
--cleanup-db
Cleanup 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. 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.
--parent-match=syspath
Trigger events for all children of a given device.
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 120
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.
--exit
Signal and wait for systemd-udevd to exit.
--log-priority=value
Set the internal log level of systemd-udevd. Valid values are the numerical syslog priorities or
their textual representations: err, info and debug.
--stop-exec-queue
Signal systemd-udevd to stop executing new events. Incoming events will be queued.
--start-exec-queue
Signal systemd-udevd to enable the execution of events.
--reload
Signal systemd-udevd to reload the rules files and other databases like the kernel module index.
Reloading rules and databases does not apply any changes to already existing devices; the new
configuration will only be applied to new events.
--property=KEY=value
Set a global property for all events.
--children-max=value
Set the maximum number of events, systemd-udevd will handle at the same time.
--timeout=seconds
The maximum number of seconds to wait for a reply from systemd-udevd.
--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 hwdb [options]
Maintain the hardware database index in /lib/udev/hwdb.bin.
--update
Compile the hardware database information located in /lib/udev/hwdb.d/, /etc/udev/hwdb.d/ and store
it in /lib/udev/hwdb.bin. This should be done after any update to the source files; it will not be
called automatically. The running udev daemon will detect a new database on its own and does not need
to be notified about it.
--test=string
Query the database with a modalias string, and print the retrieved properties.
--root=string
Alternative root path in the filesystem for reading and writing files.
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.
udevadm test-builtin [options] command devpath
Run a built-in command for the given device, and print debug output.
--help
Print help text.
SEE ALSO
udev(7)systemd-udevd.service(8)