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    <!ENTITY xmllint "<command>xmllint</command>">
]>

<refentry>

<refentryinfo>
    <title>xmllint Manual</title>
    <productname>libxml2</productname>
    <copyright>
        <year>2001</year>
        <year>2004</year>
    </copyright>
    <authorgroup>
        <author>
            <firstname>John</firstname>
            <surname>Fleck</surname>
            <affiliation>
                <address>
                    <email>jfleck@inkstain.net</email>
                </address>
            </affiliation>
        </author>
        <author>
            <firstname>Ziying</firstname>
            <surname>Sherwin</surname>
            <affiliation>
                <address>
                    <email>sherwin@nlm.nih.gov</email>
                </address>
            </affiliation>
        </author>
        <author>
            <firstname>Heiko</firstname>
            <surname>Rupp</surname>
            <affiliation>
                <address>
                    <email>hwr@pilhuhn.de</email>
                </address>
            </affiliation>
        </author>
    </authorgroup>
    <!-- still a bit buggy output, will talk to docbook-xsl upstream to fix this -->
    <!-- <releaseinfo>This is release 0.5 of the xmllint Manual.</releaseinfo> -->
    <!-- <edition>0.5</edition> -->
</refentryinfo>

<refmeta>
    <refentrytitle>xmllint</refentrytitle>
    <manvolnum>1</manvolnum>
</refmeta>

<refnamediv>
    <refname>xmllint</refname>
    <refpurpose>command line <acronym>XML</acronym> tool</refpurpose>
</refnamediv>

<refsynopsisdiv>
    <cmdsynopsis>
    <command>xmllint</command>
        <group choice="opt">
            <arg choice="plain"><option>--version</option></arg>
            <arg choice="plain"><option>--debug</option></arg>
            <arg choice="plain"><option>--quiet</option></arg>
            <arg choice="plain"><option>--shell</option></arg>
            <arg choice="plain"><option>--xpath "<replaceable class="option">XPath_expression</replaceable>"</option></arg>
            <arg choice="plain"><option>--debugent</option></arg>
            <arg choice="plain"><option>--copy</option></arg>
            <arg choice="plain"><option>--recover</option></arg>
            <arg choice="plain"><option>--nodict</option></arg>
            <arg choice="plain"><option>--noent</option></arg>
            <arg choice="plain"><option>--noout</option></arg>
            <arg choice="plain"><option>--nonet</option></arg>
            <arg choice="plain"><option>--path "<replaceable class="option">PATH(S)</replaceable>"</option></arg>
            <arg choice="plain"><option>--load-trace</option></arg>
            <arg choice="plain"><option>--htmlout</option></arg>
            <arg choice="plain"><option>--nowrap</option></arg>
            <arg choice="plain"><option>--valid</option></arg>
            <arg choice="plain"><option>--postvalid</option></arg>
            <arg choice="plain"><option>--dtdvalid <replaceable class="option">URL</replaceable></option></arg>
            <arg choice="plain"><option>--dtdvalidfpi <replaceable class="option">FPI</replaceable></option></arg>
            <arg choice="plain"><option>--timing</option></arg>
            <arg choice="plain"><option>--output <replaceable class="option">FILE</replaceable></option></arg>
            <arg choice="plain"><option>--repeat</option></arg>
            <arg choice="plain"><option>--insert</option></arg>
            <arg choice="plain"><option>--compress</option></arg>
            <arg choice="plain"><option>--html</option></arg>
            <arg choice="plain"><option>--xmlout</option></arg>
            <arg choice="plain"><option>--push</option></arg>
            <arg choice="plain"><option>--memory</option></arg>
            <arg choice="plain"><option>--max-ampl <replaceable class="option">INTEGER</replaceable></option></arg>
            <arg choice="plain"><option>--maxmem <replaceable class="option">NBBYTES</replaceable></option></arg>
            <arg choice="plain"><option>--nowarning</option></arg>
            <arg choice="plain"><option>--noblanks</option></arg>
            <arg choice="plain"><option>--nocdata</option></arg>
            <arg choice="plain"><option>--format</option></arg>
            <arg choice="plain"><option>--encode <replaceable class="option">ENCODING</replaceable></option></arg>
            <arg choice="plain"><option>--dropdtd</option></arg>
            <arg choice="plain"><option>--nsclean</option></arg>
            <arg choice="plain"><option>--testIO</option></arg>
            <arg choice="plain"><option>--catalogs</option></arg>
            <arg choice="plain"><option>--nocatalogs</option></arg>
            <arg choice="plain"><option>--auto</option></arg>
            <arg choice="plain"><option>--xinclude</option></arg>
            <arg choice="plain"><option>--noxincludenode</option></arg>
            <arg choice="plain"><option>--loaddtd</option></arg>
            <arg choice="plain"><option>--dtdattr</option></arg>
            <arg choice="plain"><option>--stream</option></arg>
            <arg choice="plain"><option>--walker</option></arg>
            <arg choice="plain"><option>--pattern <replaceable class="option">PATTERNVALUE</replaceable></option></arg>
            <arg choice="plain"><option>--chkregister</option></arg>
            <arg choice="plain"><option>--relaxng <replaceable class="option">SCHEMA</replaceable></option></arg>
            <arg choice="plain"><option>--schema <replaceable class="option">SCHEMA</replaceable></option></arg>
            <arg choice="plain"><option>--c14n</option></arg>
            <arg choice="plain"><option>--pedantic</option></arg>
        </group>
        <group choice="req">
            <arg choice="plain" rep="repeat"><replaceable>XML-FILE(S)</replaceable></arg>
            <arg choice="plain" rep="norepeat">-</arg>
        </group>
    </cmdsynopsis>
    <cmdsynopsis>
        <command>xmllint</command>
        <arg choice="plain"><option>--help</option></arg>
    </cmdsynopsis>
</refsynopsisdiv>

<refsect1 id="description">
    <title>DESCRIPTION</title>
    <para>
        The &xmllint; program parses one or more <acronym>XML</acronym> files,
        specified on the command line as <replaceable>XML-FILE</replaceable>
        (or the standard input if the filename provided
        is <emphasis role="bold">-</emphasis> ). It prints various types of
        output, depending upon the options selected. It is useful for detecting
        errors both in <acronym>XML</acronym> code and in
        the <acronym>XML</acronym> parser itself.
    </para>
    <para>&xmllint; is included in <citerefentry>
        <refentrytitle>libxml</refentrytitle>
        <manvolnum>3</manvolnum>
    </citerefentry>.</para>
</refsect1>

<refsect1 id="options">
    <title>OPTIONS</title>
    <para>
        &xmllint; accepts the following options (in alphabetical order):
    </para>

    <variablelist>

        <varlistentry>
            <term><option>--auto</option></term>
            <listitem>
                <para>Generate a small document for testing purposes.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--catalogs</option></term>
            <listitem>
                <para>
                    Use the <acronym>SGML</acronym> catalog(s) from <envar>SGML_CATALOG_FILES</envar>.
                    Otherwise <acronym>XML</acronym> catalogs starting
                    from <filename>/etc/xml/catalog</filename> or, more specifically,
                    <filename>${sysconfdir}/xml/catalog</filename> are used by default.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--chkregister</option></term>
            <listitem>
                <para>
                    Turn on node registration. Useful for developers testing <citerefentry>
                <refentrytitle>libxml</refentrytitle>
                <manvolnum>3</manvolnum>
            </citerefentry> node tracking code.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--compress</option></term>
            <listitem>
                <para>
                    Turn on <citerefentry>
                <refentrytitle>gzip</refentrytitle>
                <manvolnum>1</manvolnum>
            </citerefentry> compression of output.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--copy</option></term>
            <listitem>
                <para>Test the internal copy implementation.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--c14n</option></term>
            <listitem>
                <para>
                    Use the W3C <acronym>XML</acronym> Canonicalisation (<acronym>C14N</acronym>) to
                    serialize the result of parsing to <filename class="devicefile">stdout</filename>.
                    It keeps comments in the result.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--dtdvalid <replaceable class="option">URL</replaceable></option></term>
            <listitem>
                <para>
                    Use the <acronym>DTD</acronym> specified by
                    an <replaceable>URL</replaceable> for validation.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--dtdvalidfpi <replaceable class="option">FPI</replaceable></option></term>
            <listitem>
                <para>
                    Use the <acronym>DTD</acronym> specified by a Formal Public
                    Identifier <replaceable>FPI</replaceable> for validation, note that this
                    will require a catalog exporting that Formal Public Identifier to work.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--debug</option></term>
            <listitem>
                <para>
                    Parse a file and output an annotated tree of the
                    in-memory version of the document.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--debugent</option></term>
            <listitem>
                <para>Debug the entities defined in the document.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--dropdtd</option></term>
            <listitem>
                <para>Remove <acronym>DTD</acronym> from output.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--dtdattr</option></term>
            <listitem>
                <para>
                    Fetch external <acronym>DTD</acronym> and populate the tree with
                    inherited attributes.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--encode <replaceable class="option">ENCODING</replaceable></option></term>
            <listitem>
                <para>Output in the given encoding. Note that this works for full document not fragments or result from XPath queries.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--format</option></term>
            <listitem>
                <para>
                    Reformat and reindent the output. The <envar>XMLLINT_INDENT</envar>
                    environment variable controls the indentation. The default value is two
                    spaces &quot;  &quot;).
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--help</option></term>
            <listitem>
                <para>Print out a short usage summary for &xmllint;.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--html</option></term>
            <listitem>
                <para>Use the <acronym>HTML</acronym> parser.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--htmlout</option></term>
            <listitem>
                <para>
                    Output results as an <acronym>HTML</acronym> file. This
                    causes &xmllint; to output the necessary <acronym>HTML</acronym>
                    tags surrounding the result tree output so the results can be
                    displayed/viewed in a browser.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--insert</option></term>
            <listitem>
                <para>Test for valid insertions.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--loaddtd</option></term>
            <listitem>
                <para>Fetch an external <acronym>DTD</acronym>.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--load-trace</option></term>
            <listitem>
                <para>
                    Display all the documents loaded during the processing
                    to <filename class="devicefile">stderr</filename>.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--max-ampl <replaceable class="option">INTEGER</replaceable></option></term>
            <listitem>
                <para>
                    Set the maximum amplification factor which protects against
                    exponential entity expansion ("billion laughs"). The default value
                    is 5. Documents making heavy use of entity expansion may require a
                    higher value.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--maxmem <replaceable class="option">NNBYTES</replaceable></option></term>
            <listitem>
                <para>
                    Test the parser memory support. <replaceable>NNBYTES</replaceable>
                    is the maximum number of bytes the library is allowed to allocate.
                    This can also be used to make sure batch processing
                    of <acronym>XML</acronym> files will not exhaust the virtual memory
                    of the server running them.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--memory</option></term>
            <listitem>
                <para>Parse from memory.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--noblanks</option></term>
            <listitem>
                <para>Drop ignorable blank spaces.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--nocatalogs</option></term>
            <listitem>
                <para>Do not use any catalogs.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--nocdata</option></term>
            <listitem>
                <para>Substitute CDATA section by equivalent text nodes.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--nodict</option></term>
            <listitem>
                <para>
                    Don't use dictionaries (parser option XML_PARSE_NODICT).
                    Only for debugging.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--noent</option></term>
            <listitem>
                <para>
                    Substitute entity values for entity references. By default, &xmllint;
                    leaves entity references in place.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--nonet</option></term>
            <listitem>
                <para>
                    Do not use the Internet to fetch <acronym>DTD</acronym>s or entities.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--noout</option></term>
            <listitem>
                <para>
                    Suppress output. By default, &xmllint; outputs the result tree.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--nowarning</option></term>
            <listitem>
                <para>Do not emit warnings from the parser and/or validator.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--nowrap</option></term>
            <listitem>
                <para>Do not output <acronym>HTML</acronym> doc wrapper.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--noxincludenode</option></term>
            <listitem>
                <para>
                    Do XInclude processing but do not generate XInclude start and end nodes.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--nsclean</option></term>
            <listitem>
                <para>Remove redundant namespace declarations.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--output <replaceable class="option">FILE</replaceable></option></term>
            <listitem>
                <para>
                    Define a file path where &xmllint; will save the result of parsing.
                    Usually the programs build a tree and save it
                    on <filename class="devicefile">stdout</filename>, with this option
                    the result <acronym>XML</acronym> instance will be saved onto a file.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--path "<replaceable class="option">PATH(S)</replaceable>"</option></term>
            <listitem>
                <para>
                    Use the (space- or colon-separated) list of filesystem paths specified
                    by <replaceable>PATHS</replaceable> to load <acronym>DTD</acronym>s or
                    entities. Enclose space-separated lists by quotation marks.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--pattern <replaceable class="option">PATTERNVALUE</replaceable></option></term>
            <listitem>
                <para>
                    Used to exercise the pattern recognition engine, which can be used
                    with the reader interface to the parser. It allows to select some
                    nodes in the document based on an XPath (subset) expression. Used
                    for debugging.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--pedantic</option></term>
            <listitem>
                <para>Enable additional warnings.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--postvalid</option></term>
            <listitem>
                <para>Validate after parsing has completed.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--push</option></term>
            <listitem>
                <para>Use the push mode of the parser.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--quiet</option></term>
            <listitem>
                <para>Don't print informational messages to stderr.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--recover</option></term>
            <listitem>
                <para>Output any parsable portions of an invalid document.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--relaxng <replaceable class="option">SCHEMA</replaceable></option></term>
            <listitem>
                <para>
                    Use RelaxNG file named <replaceable class="option">SCHEMA</replaceable>
                    for validation.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--repeat</option></term>
            <listitem>
                <para>Repeat 100 times, for timing or profiling.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--schema <replaceable>SCHEMA</replaceable></option></term>
            <listitem>
                <para>
                    Use a W3C <acronym>XML</acronym> Schema file
                    named <replaceable>SCHEMA</replaceable> for validation.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--shell</option></term>
            <listitem>
                <para>
                    Run a navigating shell. Details on available commands in shell mode
                    are below (see <xref linkend="shell"/>).
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--xpath "<replaceable class="option">XPath_expression</replaceable>"</option></term>
            <listitem>
                <para>
                    Run an XPath expression given as argument and print the
                    result. In case of a nodeset result, each node in the
                    node set is serialized in full in the output. In case
                    of an empty node set the "XPath set is empty" result
                    will be shown and an error exit code will be returned.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--stream</option></term>
            <listitem>
                <para>
                    Use streaming <acronym>API</acronym> - useful when used in combination
                    with <option>--relaxng</option> or <option>--valid</option> options
                    for validation of files that are too large to be held in memory.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--testIO</option></term>
            <listitem>
                <para>Test user input/output support.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--timing</option></term>
            <listitem>
                <para>
                    Output information about the time it takes &xmllint; to perform the
                    various steps.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--valid</option></term>
            <listitem>
                <para>
                    Determine if the document is a valid instance of the included
                    Document Type Definition (<acronym>DTD</acronym>).
                    A <acronym>DTD</acronym> to be validated against also can be
                    specified at the command line using the <option>--dtdvalid</option>
                    option. By default, &xmllint; also checks to determine if the
                    document is well-formed.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--version</option></term>
            <listitem>
                <para>
                    Display the version of <citerefentry>
                <refentrytitle>libxml</refentrytitle>
                <manvolnum>3</manvolnum>
            </citerefentry> used.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--walker</option></term>
            <listitem>
                <para>
                    Test the walker module, which is a reader interface but for a
                    document tree, instead of using the reader <acronym>API</acronym> on
                    an unparsed document it works on an existing in-memory tree. Used for
                    debugging.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--xinclude</option></term>
            <listitem>
                <para>Do XInclude processing.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>--xmlout</option></term>
            <listitem>
                <para>
                    Used in conjunction with <option>--html</option>. Usually
                    when <acronym>HTML</acronym> is parsed the document is saved with
                    the <acronym>HTML</acronym> serializer. But with this option the
                    resulting document is saved with the <acronym>XML</acronym>
                    serializer. This is primarily used to
                    generate <acronym>XHTML</acronym> from <acronym>HTML</acronym> input.
                </para>
            </listitem>
        </varlistentry>

    </variablelist>
</refsect1>

<refsect1 id="shell">
    <title>SHELL COMMANDS</title>
    <para>
        &xmllint; offers an interactive shell mode invoked with
        the <option>--shell</option> command. Available commands in shell mode
        include (in alphabetical order):
    </para>
    <variablelist>

        <varlistentry>
            <term><command>base</command></term>
            <listitem>
                <para>Display <acronym>XML</acronym> base of the node.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>bye</command></term>
            <listitem>
                <para>Leave the shell.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>cat <replaceable>NODE</replaceable></command></term>
            <listitem>
                <para>Display the given node or the current one.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>cd <replaceable>PATH</replaceable></command></term>
            <listitem>
                <para>
                    Change the current node to the given path (if unique) or root if no
                    argument is given.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>dir <replaceable>PATH</replaceable></command></term>
            <listitem>
                <para>
                    Dumps information about the node (namespace, attributes, content).
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>du <replaceable>PATH</replaceable></command></term>
            <listitem>
                <para>
                    Show the structure of the subtree under the given path or the current node.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>exit</command></term>
            <listitem>
                <para>Leave the shell.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>help</command></term>
            <listitem>
                <para>Show this help.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>free</command></term>
            <listitem>
                <para>Display memory usage.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>load <replaceable>FILENAME</replaceable></command></term>
            <listitem>
                <para>Load a new document with the given filename.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>ls <replaceable>PATH</replaceable></command></term>
            <listitem>
                <para>List contents of the given path or the current directory.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>pwd</command></term>
            <listitem>
                <para>Display the path to the current node.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>quit</command></term>
            <listitem>
                <para>Leave the shell.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>save <replaceable>FILENAME</replaceable></command></term>
            <listitem>
                <para>
                    Save the current document to the given filename or to the original name.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><option>validate</option></term>
            <listitem>
                <para>Check the document for errors.</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><command>write <replaceable>FILENAME</replaceable></command></term>
            <listitem>
                <para>Write the current node to the given filename.</para>
            </listitem>
        </varlistentry>

    </variablelist>
</refsect1>

<refsect1 id="environment">
    <title>ENVIRONMENT</title>
    <variablelist>

        <varlistentry>
            <term><envar>SGML_CATALOG_FILES</envar></term>
            <listitem>
                <para><acronym>SGML</acronym> catalog behavior can be changed by redirecting
                    queries to the user's own set of catalogs. This can be done by setting
                    the <envar>SGML_CATALOG_FILES</envar> environment variable to a list
                    of catalogs. An empty one should deactivate loading the
                    default catalog.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><envar>XML_CATALOG_FILES</envar></term>
            <listitem>
                <para><acronym>XML</acronym> catalog behavior can be changed by redirecting
                    queries to the user's own set of catalogs. This can be done by setting
                    the <envar>XML_CATALOG_FILES</envar> environment variable to a space-separated
                    list of catalogs. Use percent-encoding to escape spaces or other characters.
                    An empty variable should deactivate loading the default catalog.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><envar>XML_DEBUG_CATALOG</envar></term>
            <listitem>
                <para>Setting the environment variable <envar>XML_DEBUG_CATALOG</envar>
                    to <parameter>non-zero</parameter> using the <command>export</command>
                    command outputs debugging information related to catalog operations.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><envar>XMLLINT_INDENT</envar></term>
            <listitem>
                <para>Setting the environment variable <envar>XMLLINT_INDENT</envar>
                    controls the indentation. The default value is two spaces &quot;  &quot;.
                </para>
            </listitem>
        </varlistentry>

    </variablelist>
</refsect1>

<refsect1 id="diagnostics">
    <title>DIAGNOSTICS</title>
    <para>
        &xmllint; return codes provide information that can be used when
        calling it from scripts.
    </para>
    <!-- better use segmentedlist element later,
         which is currently only supported in snapshots -->
    <variablelist>

        <varlistentry>
            <term><errorcode>0</errorcode></term>
            <listitem>
                <para>No error</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>1</errorcode></term>
            <listitem>
                <para>Unclassified</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>2</errorcode></term>
            <listitem>
                <para>Error in <acronym>DTD</acronym></para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>3</errorcode></term>
            <listitem>
                <para>Validation error</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>4</errorcode></term>
            <listitem>
                <para>Validation error</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>5</errorcode></term>
            <listitem>
                <para>Error in schema compilation</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>6</errorcode></term>
            <listitem>
                <para>Error writing output</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>7</errorcode></term>
            <listitem>
                <para>
                    Error in pattern (generated when <option>--pattern</option> option is used)
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>8</errorcode></term>
            <listitem>
                <para>
                    Error in Reader registration (generated
                    when <option>--chkregister</option> option is used)
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>9</errorcode></term>
            <listitem>
                <para>Out of memory error</para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><errorcode>10</errorcode></term>
            <listitem>
                <para>XPath evaluation error</para>
            </listitem>
        </varlistentry>

    </variablelist>
</refsect1>

<refsect1 id="seealso">
    <title>SEE ALSO</title>
    <para><citerefentry>
            <refentrytitle>libxml</refentrytitle>
            <manvolnum>3</manvolnum>
        </citerefentry>
    </para>
    <para>
        More information can be found at
        <itemizedlist>
            <listitem>
                <para><citerefentry>
                        <refentrytitle>libxml</refentrytitle>
                        <manvolnum>3</manvolnum>
                    </citerefentry> web page <ulink url="https://gitlab.gnome.org/GNOME/libxml2"/>
                </para>
            </listitem>
        </itemizedlist>
    </para>
</refsect1>

</refentry>
