UDEVADM(8)			    udevadm			    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.

       --run
	   The udev runtime directory: /run/udev.

       --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 udevd to exit.

       --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.

       --timeout=seconds
	   The maximum number seonds to wait for a reply from 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 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				  07/30/2011			    UDEVADM(8)