xmllint

command line XML tool

TLDR

Return all nodes (tags) named "foo"

$ xmllint --xpath "//[foo]" [source_file.xml]

Return the contents of the first node named "foo" as a string

$ xmllint --xpath "string(//[foo])" [source_file.xml]

Return the href attribute of the second anchor element in an html file

$ xmllint --html --xpath "string(//a[2]/@href)" webpage.xhtml

Return human-readable (indented) XML from file

$ xmllint --format [source_file.xml]

Check that a XML file meets the requirements of its DOCTYPE declaration

$ xmllint --valid [source_file.xml]

Validate XML against DTD schema hosted online

$ xmllint --dtdvalid [URL] [source_file.xml]

' xmllint 'u xmllint [ --version | --debug | --shell | --xpath " XPath_expression " | --debugent | --copy | --recover | --noent | --noout | --nonet | --path " PATH(S) " | --load -trace | --htmlout | --nowrap | --valid | --postvalid | --dtdvalid URL | --dtdvalidfpi FPI | --timing | --output FILE | --repeat | --insert | --compress | --html | --xmlout | --push | --memory | --maxmem NBBYTES | --nowarning | --noblanks | --nocdata | --format | --encode ENCODING | --dropdtd | --nsclean | --testIO | --catalogs | --nocatalogs | --auto | --xinclude | --noxincludenode | --loaddtd | --dtdattr | --stream | --walker | --pattern PATTERNVALUE | --chkregister | --relaxng SCHEMA | --schema SCHEMA | --c14n ]{ XML-FILE(S) ...| -} ' xmllint 'u xmllint --help

DESCRIPTION

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).

OPTIONS

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 URL Use the DTD specified by an URL for validation .

--dtdvalidfpi FPI 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 ENCODING Output in the given encoding . Note that this works for full document not fragments or result from XPath queries .

--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 NNBYTES 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 FILE 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 " PATH(S) " 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 PATTERNVALUE 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 SCHEMA Use RelaxNG file named SCHEMA for validation .

--repeat Repeat 100 times, for timing or profiling .

--schema SCHEMA 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 COMMANDS .

--xpath " XPath_expression " 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 .

--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 .

SHELL COMMANDS

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 NODE Display the given node or the current one .

cd PATH Change the current node to the given path (if unique) or root if no argument is given .

dir PATH Dumps information about the node (namespace, attributes, content) .

du PATH 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 FILENAME Load a new document with the given filename .

ls PATH List contents of the given path or the current directory .

pwd Display the path to the current node .

quit Leave the shell .

save FILENAME Save the current document to the given filename or to the original name .

validate Check the document for errors .

write FILENAME Write the current node to the given filename .

ENVIRONMENT

SGML_CATALOG_FILES SGML catalog behavior can be changed by redirecting queries to the user (Aqs 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_FILES XML catalog behavior can be changed by redirecting queries to the user (Aqs 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 .

XML_DEBUG_CATALOG Setting the environment variable XML_DEBUG_CATALOG to non-zero using the export command outputs debugging information related to catalog operations .

XMLLINT_INDENT Setting the environment variable XMLLINT_INDENT controls the indentation . The default value is two spaces " " .

DIAGNOSTICS

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

0 No error

1 Unclassified

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

AUTHORS

JohnFleck < jfleck@inkstain .net > Author.

ZiyingSherwin < sherwin@nlm .nih .gov > Author.

HeikoRupp < hwr@pilhuhn .de > Author.