UDEVADM(8)							      udevadm								UDEVADM(8)

NAME

       udevadm - udev management tool

SYNOPSIS

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

       udevadm info [options] [devpath]

       udevadm trigger [options] [devpath]

       udevadm settle [options]

       udevadm control option

       udevadm monitor [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 systemd-udevd, requests kernel events, manages
       the event queue, and provides simple debugging mechanisms.

OPTIONS

       -d, --debug
	   Print debug messages to standard error.

       --version
	   Print a short version string and exit.

       -h, --help
	   Print a short help text and exit.

   udevadm info [options] [devpath|file]
       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.

       -q, --query=TYPE
	   Query the database for the specified type of device data. It needs the --path or --name to identify the specified device. Valid TYPEs
	   are: name, symlink, path, property, all.

       -p, --path=DEVPATH
	   The /sys path of the device to query, e.g.  [/sys]/class/block/sda. Note that this option usually is not very useful, since udev can
	   guess the type of the argument, so udevadm --devpath=/class/block/sda is equivalent to udevadm /sys/class/block/sda.

       -n, --name=FILE
	   The name of the device node or a symlink to query, e.g.  [/dev]/sda. Note that this option usually is not very useful, since udev can
	   guess the type of the argument, so udevadm --name=sda is equivalent to udevadm /dev/sda.

       -r, --root
	   Print absolute paths in name or symlink query.

       -a, --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.

       -x, --export
	   Print output as key/value pairs. Values are enclosed in single quotes.

       -P, --export-prefix=NAME
	   Add a prefix to the key name of exported values.

       -d, --device-id-of-file=FILE
	   Print major/minor numbers of the underlying device, where the file lives on.

       -e, --export-db
	   Export the content of the udev database.

       -c, --cleanup-db
	   Cleanup the udev database.

       --version
	   Print a short version string and exit.

       -h, --help
	   Print a short help text and exit.

       In addition, an optional positional argument can be used to specify a device name or a sys path. It must start with /dev or /sys
       respectively.

   udevadm trigger [options] [devpath|file...]
       Request device events from the kernel. Primarily used to replay events at system coldplug time.

       -v, --verbose
	   Print the list of devices which will be triggered.

       -n, --dry-run
	   Do not actually trigger the event.

       -t, --type=TYPE
	   Trigger a specific type of devices. Valid types are: devices, subsystems. The default value is devices.

       -c, --action=ACTION
	   Type of event to be triggered. The default value is change.

       -s, --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.

       -S, --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.

       -a, --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.

       -A, --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.

       -p, --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.

       -g, --tag-match=PROPERTY
	   Trigger events for devices with a matching tag. This option can be specified multiple times.

       -y, --sysname-match=PATH
	   Trigger events for devices for which the last component (i.e. the filename) of the /sys path matches the specified PATH. This option
	   can be specified multiple times and also supports shell style pattern matching.

       --name-match=NAME
	   Trigger events for devices with a matching device path. This option can be specified multiple times.

       -b, --parent-match=SYSPATH
	   Trigger events for all children of a given device.

       --version
	   Print a short version string and exit.

       -h, --help
	   Print a short help text and exit.

       In addition, optional positional arguments can be used to specify device names or sys paths. They must start with /dev or /sys
       respectively.

   udevadm settle [options]
       Watches the udev event queue, and exits if all current events are handled.

       -t, --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.

       -E, --exit-if-exists=FILE
	   Stop waiting if file exists.

       --version
	   Print a short version string and exit.

       -h, --help
	   Print a short help text and exit.

   udevadm control option
       Modify the internal state of the running udev daemon.

       -e, --exit
	   Signal and wait for systemd-udevd to exit.

       -l, --log-priority=value
	   Set the internal log level of systemd-udevd. Valid values are the numerical syslog priorities or their textual representations: emerg,
	   alert, crit, err, warning, notice, info, and debug.

       -s, --stop-exec-queue
	   Signal systemd-udevd to stop executing new events. Incoming events will be queued.

       -S, --start-exec-queue
	   Signal systemd-udevd to enable the execution of events.

       -R, --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.

       -p, --property=KEY=value
	   Set a global property for all events.

       -m, --children-max=value
	   Set the maximum number of events, systemd-udevd will handle at the same time.

       -t, --timeout=seconds
	   The maximum number of seconds to wait for a reply from systemd-udevd.

       --version
	   Print a short version string and exit.

       -h, --help
	   Print a short help text and exit.

   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.

       -k, --kernel
	   Print the kernel uevents.

       -u, --udev
	   Print the udev event after the rule processing.

       -p, --property
	   Also print the properties of the event.

       -s, --subsystem-match=string[/string]
	   Filter kernel uevents and udev events by subsystem[/devtype]. Only events with a matching subsystem value will pass.

       -t, --tag-match=string
	   Filter udev events by tag. Only udev events with a given tag attached will pass.

       --version
	   Print a short version string and exit.

       -h, --help
	   Print a short help text and exit.

   udevadm test [options] [devpath]
       Simulate a udev event run for the given device, and print debug output.

       -a, --action=string
	   The action string.

       -N, --resolve-names=early|late|never
	   Specify when udevadm should resolve names of users and groups. When set to early (the default), names will be resolved when the rules
	   are parsed. When set to late, names will be resolved for every event. When set to never, names will never be resolved and all devices
	   will be owned by root.

       --version
	   Print a short version string and exit.

       -h, --help
	   Print a short help text and exit.

   udevadm test-builtin [options] [command] [devpath]
       Run a built-in command COMMAND for device DEVPATH, and print debug output.

       --version
	   Print a short version string and exit.

       -h, --help
	   Print a short help text and exit.

SEE ALSO

       udev(7), systemd-udevd.service(8)

systemd 237																UDEVADM(8)