Commands: info Query sysfs or the udev database trigger Request events from the kernel settle Wait for pending udev events control Control the udev daemon monitor Listen to kernel and udev events test Test an event run test-builtin Test a built-in command
See the udevadm(8) man page for details.
$ udevadm info --help udevadm info [OPTIONS] [DEVPATH|FILE]
Query sysfs or the udev database.
-h --help Print this message -V --version Print version of the program -q --query=TYPE Query device information: name Name of device node symlink Pointing to node path sysfs device path property The device properties all All values -p --path=SYSPATH sysfs device path used for query or attribute walk -n --name=NAME Node or symlink name used for query or attribute walk -r --root Prepend dev directory to path names -a --attribute-walk Print all key matches walking along the chain of parent devices -d --device-id-of-file=FILE Print major:minor of device containing this file -x --export Export key/value pairs -P --export-prefix Export the key name with a prefix -e --export-db Export the content of the udev database -c --cleanup-db Clean up the udev database -w --wait-for-initialization[=SECONDS] Wait for device to be initialized
-h --help Show this help -V --version Show package version -v --verbose Print the list of devices while running -n --dry-run Do not actually trigger the events -q --quiet Suppress error logging in triggering events -t --type= Type of events to trigger devices sysfs devices (default) subsystems sysfs subsystems and drivers -c --action=ACTION|help Event action value, default is "change" -s --subsystem-match=SUBSYSTEM Trigger devices from a matching subsystem -S --subsystem-nomatch=SUBSYSTEM Exclude devices from a matching subsystem -a --attr-match=FILE[=VALUE] Trigger devices with a matching attribute -A --attr-nomatch=FILE[=VALUE] Exclude devices with a matching attribute -p --property-match=KEY=VALUE Trigger devices with a matching property -g --tag-match=TAG Trigger devices with a matching tag -y --sysname-match=NAME Trigger devices with this /sys path --name-match=NAME Trigger devices with this /dev name -b --parent-match=NAME Trigger devices with that parent device -w --settle Wait for the triggered events to complete --wait-daemon[=SECONDS] Wait for udevd daemon to be initialized before triggering uevents --uuid Print synthetic uevent UUID
$ udevadm settle --help udevadm settle [OPTIONS]
Wait for pending udev events.
-h --help Show this help -V --version Show package version -t --timeout=SEC Maximum time to wait for events -E --exit-if-exists=FILE Stop waiting if file exists
$ udevadm settle --help udevadm settle [OPTIONS]
Wait for pending udev events.
-h --help Show this help -V --version Show package version -t --timeout=SEC Maximum time to wait for events -E --exit-if-exists=FILE Stop waiting if file exists
$ udevadm control --help udevadm control OPTION
Control the udev daemon.
-h --help Show this help -V --version Show package version -e --exit Instruct the daemon to cleanup and exit -l --log-level=LEVEL Set the udev log level for the daemon -s --stop-exec-queue Do not execute events, queue only -S --start-exec-queue Execute events, flush queue -R--reload Reload rules and databases -p --property=KEY=VALUE Set a global property for all events -m --children-max=N Maximum number of children --ping Wait for udev to respond to a ping message -t --timeout=SECONDS Maximum time to block for a reply
-h --help Show this help -V --version Show package version -p --property Print the event properties -k --kernel Print kernel uevents -u --udev Print udev events -s --subsystem-match=SUBSYSTEM[/DEVTYPE] Filter events by subsystem -t --tag-match=TAG Filter events by tag
$ udevadm test --help udevadm test [OPTIONS] DEVPATH
Test an event run.
-h --help Show this help -V --version Show package version -a --action=ACTION|help Set action string -N --resolve-names=early|late|never When to resolve names
Udevadm info starts with the device specified by the devpath and then walks up the chain of parent devices. It prints for every device found, all possible attributes in the udev rules key format. A rule to match, can be composed by the attributes of the device and the attributes from one single parent device.