NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COLOPHON

UDEVADM(8)                         udevadm                        UDEVADM(8)

NAME         top

       udevadm - udev management tool

SYNOPSIS         top

       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         top

       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         top

       --debug
           Print debug messages to standard error.

       --version
           Print version number.

       -h, --help
           Print help text.

   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 version.

       -h, --help
           Print help text.

   udevadm trigger [options]
       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=NAME
           Trigger events for devices with a matching sys device name. This
           option can be specified multiple times and supports shell style
           pattern matching.

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

       -h, --help
           Print help text.

   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.

       -h, --help
           Print help text.

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

       -x, --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:
           err, 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.

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

       -h, --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.

       -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 events by subsystem[/devtype]. Only udev events with a
           matching subsystem value will pass.

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

       -h, --help
           Print help text.

   udevadm hwdb [options]
       Maintain the hardware database index in /etc/udev/hwdb.bin.

       -u, --update
           Compile the hardware database information located in
           /usr/lib/udev/hwdb.d/, /etc/udev/hwdb.d/ and store it in
           /etc/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.

       -t, --test=string
           Query the database with a modalias string, and print the
           retrieved properties.

       -r, --root=string
           Alternative root path in the file system for reading and writing
           files.

       -h, --help
           Print help text.

   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.

       -h, --help
           Print help text.

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

       -h, --help
           Print help text.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a bug
       report for this manual page, see 
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.  This
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systemd 215                                                       UDEVADM(8)