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>systemd-udevd listens to kernel uevents. For every event, systemd-udevd executes matching
54 instructions specified in udev rules. See
<citerefentry>
55 <refentrytitle>udev
</refentrytitle><manvolnum>7</manvolnum>
56 </citerefentry>.
</para>
57 <para>The behavior of the running daemon can be changed with
58 <command>udevadm control
</command>.
</para>
61 <refsect1><title>Options
</title>
64 <term><option>--daemon
</option></term>
66 <para>Detach and run in the background.
</para>
70 <term><option>--debug
</option></term>
72 <para>Print debug messages to stderr.
</para>
76 <term><option>--children-max=
</option></term>
78 <para>Limit the number of parallel executed events.
</para>
82 <term><option>--exec-delay=
</option></term>
84 <para>Number of seconds to delay the execution of RUN instructions.
85 This might be useful when debugging system crashes during coldplug
86 cause by loading non-working kernel modules.
</para>
90 <term><option>--resolve-names=
</option></term>
92 <para>Specify when systemd-udevd should resolve names of users and groups.
93 When set to
<option>early
</option> (the default) names will be
94 resolved when the rules are parsed. When set to
95 <option>late
</option> names will be resolved for every event.
96 When set to
<option>never
</option> names will never be resolved
97 and all devices will be owned by root.
</para>
101 <term><option>--version
</option></term>
103 <para>Print version number.
</para>
107 <term><option>--help
</option></term>
109 <para>Print help text.
</para>
115 <refsect1><title>Environment
</title>
118 <term><varname>UDEV_LOG=
</varname></term>
120 <para>Set the logging priority.
</para>
126 <refsect1><title>Kernel command line
</title>
128 <para>The parameters starting with
"rd.", will be read when udev is used in an initrd.
</para>
130 <term><varname>udev.log-priority=
</varname></term>
131 <term><varname>rd.udev.log-priority=
</varname></term>
133 <para>Set the logging priority.
</para>
137 <term><varname>udev.children-max=
</varname></term>
138 <term><varname>rd.udev.children-max=
</varname></term>
140 <para>Limit the number of parallel executed events.
</para>
144 <term><varname>udev.exec-delay=
</varname></term>
145 <term><varname>rd.udev.exec-delay=
</varname></term>
147 <para>Number of seconds to delay the execution of RUN instructions.
148 This might be useful when debugging system crashes during coldplug
149 cause by loading non-working kernel modules.
</para>
156 <title>See Also
</title>
158 <refentrytitle>udev
</refentrytitle><manvolnum>7</manvolnum>
159 </citerefentry>,
<citerefentry>
160 <refentrytitle>udevadm
</refentrytitle><manvolnum>8</manvolnum>
161 </citerefentry></para>