xmllint - command line XML tool


xmllint [--version --debug --shell --debugent --copy --recover --noent --noout --nonet --path "\fBPATH(S)\fR" --load-trace --htmlout --nowrap --valid --postvalid --dtdvalid \fBURL\fR --dtdvalidfpi \fBFPI\fR --timing --output \fBFILE\fR --repeat --insert --compress --html --xmlout --push --memory --maxmem \fBNBBYTES\fR --nowarning --noblanks --nocdata --format --encode \fBENCODING\fR --dropdtd --nsclean --testIO --catalogs --nocatalogs --auto --xinclude --noxincludenode --loaddtd --dtdattr --stream --walker --pattern \fBPATTERNVALUE\fR --chkregister --relaxng \fBSCHEMA\fR --schema \fBSCHEMA\fR --c14n] {XML-FILE(S)... -} xmllint --help


The xmllint program parses one or more XML files, specified on the command line as XML-FILE (or the standard input if the filename provided is - ). It prints various types of output, depending upon the options selected. It is useful for detecting errors both in XML code and in the XML parser itself.

xmllint is included in libxml(3).


xmllint accepts the following options (in alphabetical order):

  • --auto
        Generate a small document for testing purposes.
  • --catalogs
        Use the SGML catalog(s) from SGML_CATALOG_FILES. Otherwise XML catalogs starting from /etc/xml/catalog are used by default.
  • --chkregister
        Turn on node registration. Useful for developers testing libxml(3) node tracking code.
  • --compress
        Turn on gzip(1) compression of output.
  • --copy
        Test the internal copy implementation.
  • --c14n
        Use the W3C XML Canonicalisation (C14N) to serialize the result of parsing to stdout. It keeps comments in the result.
  • --dtdvalid \fBURL\fR
        Use the DTD specified by an URL for validation.
  • --dtdvalidfpi \fBFPI\fR
        Use the DTD specified by a Formal Public Identifier FPI for validation, note that this will require a catalog exporting that Formal Public Identifier to work.
  • --debug
        Parse a file and output an annotated tree of the in-memory version of the document.
  • --debugent
        Debug the entities defined in the document.
  • --dropdtd
        Remove DTD from output.
  • --dtdattr
        Fetch external DTD and populate the tree with inherited attributes.
  • --encode \fBENCODING\fR
        Output in the given encoding.
  • --format
        Reformat and reindent the output. The XMLLINT_INDENT environment variable controls the indentation. The default value is two spaces " ").
  • --help
        Print out a short usage summary for xmllint.
  • --html
        Use the HTML parser.
  • --htmlout
        Output results as an HTML file. This causes xmllint to output the necessary HTML tags surrounding the result tree output so the results can be displayed/viewed in a browser.
  • --insert
        Test for valid insertions.
  • --loaddtd
        Fetch an external DTD.
  • --load-trace
        Display all the documents loaded during the processing to stderr.
  • --maxmem \fBNNBYTES\fR
        Test the parser memory support. NNBYTES is the maximum number of bytes the library is allowed to allocate. This can also be used to make sure batch processing of XML files will not exhaust the virtual memory of the server running them.
  • --memory
        Parse from memory.
  • --noblanks
        Drop ignorable blank spaces.
  • --nocatalogs
        Do not use any catalogs.
  • --nocdata
        Substitute CDATA section by equivalent text nodes.
  • --noent
        Substitute entity values for entity references. By default, xmllint leaves entity references in place.
  • --nonet
        Do not use the Internet to fetch DTDs or entities.
  • --noout
        Suppress output. By default, xmllint outputs the result tree.
  • --nowarning
        Do not emit warnings from the parser and/or validator.
  • --nowrap
        Do not output HTML doc wrapper.
  • --noxincludenode
        Do XInclude processing but do not generate XInclude start and end nodes.
  • --nsclean
        Remove redundant namespace declarations.
  • --output \fBFILE\fR
        Define a file path where xmllint will save the result of parsing. Usually the programs build a tree and save it on stdout, with this option the result XML instance will be saved onto a file.
  • --path "\fBPATH(S)\fR"
        Use the (space- or colon-separated) list of filesystem paths specified by PATHS to load DTDs or entities. Enclose space-separated lists by quotation marks.
  • --pattern \fBPATTERNVALUE\fR
        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.
  • --postvalid
        Validate after parsing has completed.
  • --push
        Use the push mode of the parser.
  • --recover
        Output any parsable portions of an invalid document.
  • --relaxng \fBSCHEMA\fR
        Use RelaxNG file named SCHEMA for validation.
  • --repeat
        Repeat 100 times, for timing or profiling.
  • --schema \fBSCHEMA\fR
        Use a W3C XML Schema file named SCHEMA for validation.
  • --shell
        Run a navigating shell. Details on available commands in shell mode are below (see the section called « SHELL COMMANDS »).
  • --stream
        Use streaming API - useful when used in combination with --relaxng or --valid options for validation of files that are too large to be held in memory.
  • --testIO
        Test user input/output support.
  • --timing
        Output information about the time it takes xmllint to perform the various steps.
  • --valid
        Determine if the document is a valid instance of the included Document Type Definition (DTD). A DTD to be validated against also can be specified at the command line using the --dtdvalid option. By default, xmllint also checks to determine if the document is well-formed.
  • --version
        Display the version of libxml(3) used.
  • --walker
        Test the walker module, which is a reader interface but for a document tree, instead of using the reader API on an unparsed document it works on an existing in-memory tree. Used for debugging.
  • --xinclude
        Do XInclude processing.
  • --xmlout
        Used in conjunction with --html. Usually when HTML is parsed the document is saved with the HTML serializer. But with this option the resulting document is saved with the XML serializer. This is primarily used to generate XHTML from HTML input.


xmllint offers an interactive shell mode invoked with the --shell command. Available commands in shell mode include (in alphabetical order):

  • base
        Display XML base of the node.
  • bye
        Leave the shell.
  • cat \fBNODE\fR
        Display the given node or the current one.
  • cd \fBPATH\fR
        Change the current node to the given path (if unique) or root if no argument is given.
  • dir \fBPATH\fR
        Dumps information about the node (namespace, attributes, content).
  • du \fBPATH\fR
        Show the structure of the subtree under the given path or the current node.
  • exit
        Leave the shell.
  • help
        Show this help.
  • free
        Display memory usage.
  • load \fBFILENAME\fR
        Load a new document with the given filename.
  • ls \fBPATH\fR
        List contents of the given path or the current directory.
  • pwd
        Display the path to the current node.
  • quit
        Leave the shell.
  • save \fBFILENAME\fR
        Save the current document to the given filename or to the original name.
  • validate
        Check the document for errors.
  • write \fBFILENAME\fR
        Write the current node to the given filename.


        SGML catalog behavior can be changed by redirecting queries to the user's own set of catalogs. This can be done by setting the SGML_CATALOG_FILES environment variable to a list of catalogs. An empty one should deactivate loading the default /etc/sgml/catalog catalog.
        XML catalog behavior can be changed by redirecting queries to the user's own set of catalogs. This can be done by setting the XML_CATALOG_FILES environment variable to a list of catalogs. An empty one should deactivate loading the default /etc/xml/catalog catalog.
        Setting the environment variable XML_DEBUG_CATALOG to non-zero using the export command outputs debugging information related to catalog operations.
        Setting the environment variable XMLLINT_INDENT controls the indentation. The default value is two spaces " ".


xmllint return codes provide information that can be used when calling it from scripts.

  • 0
        No error
  • 1
  • 2
        Error in DTD
  • 3
        Validation error
  • 4
        Validation error
  • 5
        Error in schema compilation
  • 6
        Error writing output
  • 7
        Error in pattern (generated when --pattern option is used)
  • 8
        Error in Reader registration (generated when --chkregister option is used)
  • 9
        Out of memory error



More information can be found at


John Fleck <>, Ziying Sherwin <>, Heiko Rupp <>.