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">
9 <productname>udev</productname>
13 <refentrytitle>udevd</refentrytitle>
14 <manvolnum>8</manvolnum>
15 <refmiscinfo class="version"></refmiscinfo>
19 <refname>udevd</refname><refpurpose>event managing daemon</refpurpose>
24 <command>udevd</command>
25 <arg><option>--daemon</option></arg>
26 <arg><option>--debug</option></arg>
27 <arg><option>--children-max=</option></arg>
28 <arg><option>--exec-delay=</option></arg>
29 <arg><option>--resolve-names=early|late|never</option></arg>
30 <arg><option>--version</option></arg>
31 <arg><option>--help</option></arg>
35 <refsect1><title>Description</title>
36 <para>udevd listens to kernel uevents. For every event, udevd executes matching
37 instructions specified in udev rules. See <citerefentry>
38 <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
39 </citerefentry>.</para>
40 <para>On startup the content of the directory <filename>/lib/udev/devices</filename>
41 is copied to <filename>/dev</filename>. If kernel modules specify static device
42 nodes, these nodes are created even wihtout a corresponding kernel device, to
43 allow on-demand loading of kernel modules. Matching permissions specified in udev
44 rules are applied to these static device nodes.</para>
45 <para>The behavior of the running daemon can be changed with
46 <command>udevadm control</command>.</para>
49 <refsect1><title>Options</title>
52 <term><option>--daemon</option></term>
54 <para>Detach and run in the background.</para>
58 <term><option>--debug</option></term>
60 <para>Print debug messages to stderr.</para>
64 <term><option>--children-max=</option></term>
66 <para>Limit the number of parallel executed events.</para>
70 <term><option>--exec-delay=</option></term>
72 <para>Number of seconds to delay the execution of RUN instructions.
73 This might be useful when debugging system crashes during coldplug
74 cause by loading non-working kernel modules.</para>
78 <term><option>--resolve-names=</option></term>
80 <para>Specify when udevd should resolve names of users and groups.
81 When set to <option>early</option> (the default) names will be
82 resolved when the rules are parsed. When set to
83 <option>late</option> names will be resolved for every event.
84 When set to <option>never</option> names will never be resolved
85 and all devices will be owned by root.</para>
89 <term><option>--version</option></term>
91 <para>Print version number.</para>
95 <term><option>--help</option></term>
97 <para>Print help text.</para>
103 <refsect1><title>Environment</title>
106 <term><varname>UDEV_LOG=</varname></term>
108 <para>Set the logging priority.</para>
114 <refsect1><title>Kernel command line</title>
117 <term><varname>udev.log-priority=</varname></term>
119 <para>Set the logging priority.</para>
123 <term><varname>udev.children-max=</varname></term>
125 <para>Limit the number of parallel executed events.</para>
129 <term><varname>udev.exec-delay=</varname></term>
131 <para>Number of seconds to delay the execution of RUN instructions.
132 This might be useful when debugging system crashes during coldplug
133 cause by loading non-working kernel modules.</para>
139 <refsect1><title>Author</title>
140 <para>Written by Kay Sievers <email>kay.sievers@vrfy.org</email>.</para>
144 <title>See Also</title>
146 <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
147 </citerefentry>, <citerefentry>
148 <refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
149 </citerefentry></para>