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<html xmlns="http://www.w3.org/1999/xhtml"><head><title>udevd</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"/></head><body><div class="refentry" title="udevd"><a id="udevd"/><div class="titlepage"/><div class="refnamediv"><h2>Name</h2><p>udevd — event managing daemon</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">udevd</code>  [<code class="option">--daemon</code>] [<code class="option">--debug</code>] [<code class="option">--children-max=</code>] [<code class="option">--exec-delay=</code>] [<code class="option">--resolve-names=early|late|never</code>] [<code class="option">--version</code>] [<code class="option">--help</code>]</p></div></div><div class="refsect1" title="Description"><a id="id310245"/><h2>Description</h2><p>udevd listens to kernel uevents. For every event, udevd executes matching
    instructions specified in udev rules. See <span class="citerefentry"><span class="refentrytitle">udev</span>(7)</span>.</p><p>On startup the content of the directory <code class="filename">/lib/udev/devices</code>
    is copied to <code class="filename">/dev</code>. If kernel modules specify static device
    nodes, these nodes are created even without a corresponding kernel device, to
    allow on-demand loading of kernel modules. Matching permissions specified in udev
    rules are applied to these static device nodes.</p><p>The behavior of the running daemon can be changed with
    <span class="command"><strong>udevadm control</strong></span>.</p></div><div class="refsect1" title="Options"><a id="id310294"/><h2>Options</h2><div class="variablelist"><dl><dt><span class="term"><code class="option">--daemon</code></span></dt><dd><p>Detach and run in the background.</p></dd><dt><span class="term"><code class="option">--debug</code></span></dt><dd><p>Print debug messages to stderr.</p></dd><dt><span class="term"><code class="option">--children-max=</code></span></dt><dd><p>Limit the number of parallel executed events.</p></dd><dt><span class="term"><code class="option">--exec-delay=</code></span></dt><dd><p>Number of seconds to delay the execution of RUN instructions.
          This might be useful when debugging system crashes during coldplug
          cause by loading non-working kernel modules.</p></dd><dt><span class="term"><code class="option">--resolve-names=</code></span></dt><dd><p>Specify when udevd should resolve names of users and groups.
          When set to <code class="option">early</code> (the default) names will be
          resolved when the rules are parsed.  When set to
          <code class="option">late</code> names will be resolved for every event.
          When set to <code class="option">never</code> names will never be resolved
          and all devices will be owned by root.</p></dd><dt><span class="term"><code class="option">--version</code></span></dt><dd><p>Print version number.</p></dd><dt><span class="term"><code class="option">--help</code></span></dt><dd><p>Print help text.</p></dd></dl></div></div><div class="refsect1" title="Environment"><a id="id276550"/><h2>Environment</h2><div class="variablelist"><dl><dt><span class="term"><code class="varname">UDEV_LOG=</code></span></dt><dd><p>Set the logging priority.</p></dd></dl></div></div><div class="refsect1" title="Kernel command line"><a id="id276577"/><h2>Kernel command line</h2><div class="variablelist"><dl><dt><span class="term"><code class="varname">udev.log-priority=</code></span></dt><dd><p>Set the logging priority.</p></dd><dt><span class="term"><code class="varname">udev.children-max=</code></span></dt><dd><p>Limit the number of parallel executed events.</p></dd><dt><span class="term"><code class="varname">udev.exec-delay=</code></span></dt><dd><p>Number of seconds to delay the execution of RUN instructions.
          This might be useful when debugging system crashes during coldplug
          cause by loading non-working kernel modules.</p></dd></dl></div></div><div class="refsect1" title="Author"><a id="id276637"/><h2>Author</h2><p>Written by Kay Sievers <code class="email">&lt;<a class="email" href="mailto:kay.sievers@vrfy.org">kay.sievers@vrfy.org</a>&gt;</code>.</p></div><div class="refsect1" title="See Also"><a id="id276651"/><h2>See Also</h2><p><span class="citerefentry"><span class="refentrytitle">udev</span>(7)</span>, <span class="citerefentry"><span class="refentrytitle">udevadm</span>(8)</span></p></div></div></body></html>