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1<?xml version='1.0'?>
2<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
3<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
4  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5
6<refentry id="udevd">
7  <refentryinfo>
8    <title>udevd</title>
9    <productname>eudev</productname>
10    <authorgroup>
11      <author>
12        <contrib>Developer</contrib>
13        <firstname>Kay</firstname>
14        <surname>Sievers</surname>
15        <email>kay@vrfy.org</email>
16      </author>
17    </authorgroup>
18  </refentryinfo>
19
20  <refmeta>
21    <refentrytitle>udevd</refentrytitle>
22    <manvolnum>8</manvolnum>
23  </refmeta>
24
25  <refnamediv>
26    <refname>udevd</refname>
27    <refpurpose>Device event managing daemon</refpurpose>
28  </refnamediv>
29
30  <refsynopsisdiv>
31    <para><filename>udevd</filename></para>
32
33    <cmdsynopsis>
34      <command>/sbin/udevd</command>
35      <arg><option>--daemon</option></arg>
36      <arg><option>--debug</option></arg>
37      <arg><option>--children-max=</option></arg>
38      <arg><option>--exec-delay=</option></arg>
39      <arg><option>--event-timeout=</option></arg>
40      <arg><option>--resolve-names=early|late|never</option></arg>
41      <arg><option>--version</option></arg>
42      <arg><option>--help</option></arg>
43    </cmdsynopsis>
44
45  </refsynopsisdiv>
46
47  <refsect1><title>Description</title>
48    <para><command>udevd</command> listens to kernel uevents.
49    For every event, udevd executes matching instructions
50    specified in udev rules. See <citerefentry>
51    <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
52    </citerefentry>.</para>
53
54    <para>The behavior of the daemon can be configured using
55    <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
56    its command-line options, environment variables, and on the kernel
57    command-line, or changed dynamically with <command>udevadm
58    control</command>.
59    </para>
60  </refsect1>
61
62  <refsect1><title>Options</title>
63    <variablelist>
64      <varlistentry>
65        <term><option>-d</option>, <option>--daemon</option></term>
66        <listitem>
67          <para>Detach and run in the background.</para>
68        </listitem>
69      </varlistentry>
70
71      <varlistentry>
72        <term><option>-D</option>, <option>--debug</option></term>
73        <listitem>
74          <para>Print debug messages to standard error.</para>
75        </listitem>
76      </varlistentry>
77
78      <varlistentry>
79        <term><option>-c</option>, <option>--children-max=</option></term>
80        <listitem>
81          <para>Limit the number of events executed in parallel.</para>
82        </listitem>
83      </varlistentry>
84
85      <varlistentry>
86        <term><option>-e</option>, <option>--exec-delay=</option></term>
87        <listitem>
88          <para>Delay the execution of <varname>RUN</varname>
89          instructions by the given number of seconds. This option
90          might be useful when debugging system crashes during
91          coldplug caused by loading non-working kernel
92          modules.</para>
93        </listitem>
94      </varlistentry>
95
96      <varlistentry>
97        <term><option>-t</option>, <option>--event-timeout=</option></term>
98        <listitem>
99          <para>Set the number of seconds to wait for events to finish. After
100          this time the event will be terminated. The default is 30 seconds.</para>
101        </listitem>
102      </varlistentry>
103
104      <varlistentry>
105        <term><option>-N</option>, <option>--resolve-names=</option></term>
106        <listitem>
107          <para>Specify when udevd should resolve names of users and groups.
108          When set to <option>early</option> (the default), names will be
109          resolved when the rules are parsed.  When set to
110          <option>late</option>, names will be resolved for every event.
111          When set to <option>never</option>, names will never be resolved
112          and all devices will be owned by root.</para>
113        </listitem>
114      </varlistentry>
115
116      <varlistentry>
117        <term><option>-h</option>, <option>--help</option></term>
118
119      </varlistentry>
120    </variablelist>
121  </refsect1>
122
123  <refsect1><title>Kernel command line</title>
124    <variablelist class='kernel-commandline-options'>
125      <para>Parameters starting with "rd." will be read when
126      <command>udevd</command> is used in an initrd.</para>
127      <varlistentry>
128        <term><varname>udev.log-priority=</varname></term>
129        <term><varname>rd.udev.log-priority=</varname></term>
130        <listitem>
131          <para>Set the log level.</para>
132        </listitem>
133      </varlistentry>
134      <varlistentry>
135        <term><varname>udev.children-max=</varname></term>
136        <term><varname>rd.udev.children-max=</varname></term>
137        <listitem>
138          <para>Limit the number of events executed in parallel.</para>
139        </listitem>
140      </varlistentry>
141      <varlistentry>
142        <term><varname>udev.exec-delay=</varname></term>
143        <term><varname>rd.udev.exec-delay=</varname></term>
144        <listitem>
145          <para>Delay the execution of <varname>RUN</varname> instructions by the given
146          number of seconds. This option might be useful when
147          debugging system crashes during coldplug caused by loading
148          non-working kernel modules.</para>
149        </listitem>
150      </varlistentry>
151      <varlistentry>
152        <term><varname>udev.event-timeout=</varname></term>
153        <term><varname>rd.udev.event-timeout=</varname></term>
154        <listitem>
155          <para>Wait for events to finish up to the given number
156          of seconds. This option might be useful if events are
157          terminated due to kernel drivers taking too long to initialize.</para>
158        </listitem>
159      </varlistentry>
160      <varlistentry>
161        <term><varname>net.ifnames=</varname></term>
162        <listitem>
163          <para>Network interfaces are renamed to give them predictable names
164          when possible. It is enabled by default; specifying 0 disables it.</para>
165        </listitem>
166      </varlistentry>
167    </variablelist>
168    <!-- when adding entries here, consider also adding them
169         in kernel-command-line.xml -->
170 </refsect1>
171
172  <refsect1>
173    <title>See Also</title>
174    <para>
175      <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
176      <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
177      <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry>
178    </para>
179  </refsect1>
180</refentry>
181