2 <?xml-stylesheet type=
"text/xsl" href=
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3 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.2//EN"
4 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
6 <refentry id=
"systemd-udevd.service">
8 <title>systemd-udevd.service
</title>
9 <productname>systemd
</productname>
12 <contrib>Developer
</contrib>
13 <firstname>Kay
</firstname>
14 <surname>Sievers
</surname>
15 <email>kay@vrfy.org
</email>
21 <refentrytitle>systemd-udevd.service
</refentrytitle>
22 <manvolnum>8</manvolnum>
23 <refmiscinfo class=
"version"></refmiscinfo>
27 <refname>systemd-udevd.service
</refname>
28 <refname>systemd-udevd-control.socket
</refname>
29 <refname>systemd-udevd-kernel.socket
</refname>
30 <refname>systemd-udevd
</refname>
31 <refpurpose>Device event managing daemon
</refpurpose>
35 <para><filename>systemd-udevd.service
</filename></para>
36 <para><filename>systemd-udevd-control.socket
</filename></para>
37 <para><filename>systemd-udevd-kernel.socket
</filename></para>
40 <command>/usr/lib/systemd/systemd-udevd
</command>
41 <arg><option>--daemon
</option></arg>
42 <arg><option>--debug
</option></arg>
43 <arg><option>--children-max=
</option></arg>
44 <arg><option>--exec-delay=
</option></arg>
45 <arg><option>--resolve-names=early|late|never
</option></arg>
46 <arg><option>--version
</option></arg>
47 <arg><option>--help
</option></arg>
52 <refsect1><title>Description
</title>
53 <para><command>systemd-udevd
</command> listens to kernel uevents.
54 For every event, systemd-udevd executes matching instructions
55 specified in udev rules. See
<citerefentry>
56 <refentrytitle>udev
</refentrytitle><manvolnum>7</manvolnum>
57 </citerefentry>.
</para>
58 <para>The behavior of the running daemon can be changed with
59 <command>udevadm control
</command>.
</para>
62 <refsect1><title>Options
</title>
65 <term><option>--daemon
</option></term>
67 <para>Detach and run in the background.
</para>
71 <term><option>--debug
</option></term>
73 <para>Print debug messages to stderr.
</para>
77 <term><option>--children-max=
</option></term>
79 <para>Limit the number of events executed in parallel.
</para>
83 <term><option>--exec-delay=
</option></term>
86 <para>Delay the execution of RUN intruction by the given
87 number of seconds. This option might be useful when
88 debugging system crashes during coldplug caused by loading
89 non-working kernel modules.
</para>
93 <term><option>--resolve-names=
</option></term>
95 <para>Specify when systemd-udevd should resolve names of users and groups.
96 When set to
<option>early
</option> (the default) names will be
97 resolved when the rules are parsed. When set to
98 <option>late
</option> names will be resolved for every event.
99 When set to
<option>never
</option> names will never be resolved
100 and all devices will be owned by root.
</para>
104 <term><option>--version
</option></term>
106 <para>Print version number.
</para>
110 <term><option>--help
</option></term>
112 <para>Print help text.
</para>
118 <refsect1><title>Environment
</title>
121 <term><varname>UDEV_LOG=
</varname></term>
123 <para>Set the logging priority.
</para>
129 <refsect1><title>Kernel command line
</title>
131 <para>Parameters starting with
"rd." will be read when
132 <command>systemd-udevd
</command> is used in an initrd.
</para>
134 <term><varname>udev.log-priority=
</varname></term>
135 <term><varname>rd.udev.log-priority=
</varname></term>
137 <para>Set the logging priority.
</para>
141 <term><varname>udev.children-max=
</varname></term>
142 <term><varname>rd.udev.children-max=
</varname></term>
144 <para>Limit the number of events executed in parallel.
</para>
148 <term><varname>udev.exec-delay=
</varname></term>
149 <term><varname>rd.udev.exec-delay=
</varname></term>
151 <para>Delay the execution of RUN intruction by the given
152 number of seconds. This option might be useful when
153 debugging system crashes during coldplug caused by loading
154 non-working kernel modules.
</para>
161 <title>See Also
</title>
163 <refentrytitle>udev
</refentrytitle><manvolnum>7</manvolnum>
164 </citerefentry>,
<citerefentry>
165 <refentrytitle>udevadm
</refentrytitle><manvolnum>8</manvolnum>
166 </citerefentry></para>