udevadm
udev management tool
see also :
udevd
Synopsis
udevadm
[--debug] [--version]
[--help]
udevadm info
options
udevadm trigger
[options]
udevadm settle
[options]
udevadm control
command
udevadm monitor
[options]
udevadm test [options]
devpath
udevadm test-builtin
[options] command devpath
add an example, a script, a trick and tips
examples
source
service autofs restart
udevadm control --reload_rules
udevadm trigger
source
/sbin/udevadm trigger
/sbin/udevadm settle
exit 0
source
touch /etc/auto.usb
service autofs restart
udevadm control --reload_rules
udevadm trigger
source
service udev reload
udevadm trigger
source
if [ "$1" = "configure" ]; then
udevadm trigger
fi
exit 0
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.
udevadm
test-builtin [options] command devpath
Run a built-in command for the given device, and print
debug output.
--help
Print help text.
udevadm settle
[options]
see also
udev
udevd
author
Written by Kay
Sievers kay.sievers[:at:]vrfy[:dot:]org.