systemd/extras/volume_id/vol_id.xml

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<article>
  <section>
    <title>vol_id</title>
    <refentry>
      <refentryinfo>
        <title>vol_id</title>
        <date>March 2006</date>
        <productname>volume_id</productname>
      </refentryinfo>

      <refmeta>
        <refentrytitle>vol_id</refentrytitle>
        <manvolnum>8</manvolnum>
        <refmiscinfo class="version"></refmiscinfo>
      </refmeta>

      <refnamediv>
        <refname>vol_id</refname><refpurpose>probe filesystem type and read label and uuid</refpurpose>
      </refnamediv>

      <refsynopsisdiv>
        <cmdsynopsis>
          <command>vol_id</command>
          <arg><option>--export</option></arg>
          <arg><option>-t</option></arg>
          <arg><option>-l</option></arg>
          <arg><option>-u</option></arg>
          <arg><replaceable>device</replaceable></arg>
        </cmdsynopsis>
      </refsynopsisdiv>

      <refsect1><title>DESCRIPTION</title>
        <para><command>vol_id</command> is usually called from a udev rule, to
        provide udev with the filesystem type, the label and the uuid of a
        volume. <command>vol_id</command> supports all common filesystem formats
        and detects various raid setups to prevent the recognition of raid members
        as a volume with a filesystem.</para>
      </refsect1>

      <refsect1><title>OPTIONS</title>
        <variablelist>
          <varlistentry>
            <term><option>--export</option></term>
            <listitem>
              <para>print all values in key/value format to import them into the
              environment.</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><option>-t</option></term>
            <listitem>
              <para>print the filesystem type</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><option>-l</option></term>
            <listitem>
              <para>print the label of a volume</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><option>-u</option></term>
            <listitem>
              <para>print the uuid of a volume</para>
            </listitem>
          </varlistentry>
        </variablelist>
      </refsect1>

      <refsect1><title>ENVIRONMENT</title>
        <variablelist>
          <varlistentry>
            <term><option>UDEV_LOG</option></term>
            <listitem>
              <para>Set the syslog priority.</para>
            </listitem>
          </varlistentry>
        </variablelist>
      </refsect1>

      <refsect1><title>EXIT STATUS</title>
        <para><command>vol_id</command> will only return successful if the
        value asked for is not empty. All trailing whitespace will be removed,
        spaces replaced by underscore and slashes ignored.</para>
     </refsect1>

      <refsect1><title>AUTHOR</title>
        <para>Written by Kay Sievers <email>kay.sievers@vrfy.org</email></para>
      </refsect1>

      <refsect1>
        <title>SEE ALSO</title>
        <para><citerefentry>
            <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
        </citerefentry></para>
      </refsect1>
    </refentry>
  </section>
</article>