Raptor RDF parsing and serializing utility


Convert an RDF/XML document to Turtle

$ rapper -i rdfxml -o turtle [path/to/file]

Count the number of triples in a Turtle file
$ rapper -i turtle -c [path/to/file]




rapper -o ntriples

rapper -i rss-tag-soup -o rss-1.0 pile-of-rss.xml

rapper --count


The rapper utility allows parsing of RDF content by the Raptor RDF parser toolkit emitting the results as RDF triples in a choice of syntaxes. The INPUT-URI can be a file name, '-' for standard input or if Raptor is built with a WWW retrieval library, a general URI. The optional INPUT-BASE-URI is used as the document parser base URI if present otherwise defaults to the INPUT-URI. A value of '-' means no base URI.


rapper uses the usual GNU command line syntax, with long options starting with two dashes (`-') if supported by the getopt_long function. Otherwise the short options are only available.

-h, --help

Show a summary of the options.

-i, --input FORMAT

Set the input FORMAT to one of 'rdfxml' (RDF/XML, default), 'ntriples' (N-Triples, see below), 'turtle' (Turtle, see below) or 'rss-tag-soup' (RSS Tag Soup). The RSS Tag Soup parser can turn the many XML RSS formats and Atom 0.3 into RDF triples.

The list of parsers depends on how libraptor(3) was built. The list of supported parsers is given in the help summary given by -h.

-I, --input-uri URI

Set the input/parser base URI or use value '-' for no base. The default is the INPUT-URI argument value.

-o, --output FORMAT

Set the output FORMAT to 'ntriples' (N-Triples, default), 'rdfxml' (RDF/XML), 'rdfxml-abbrev' (RDF/XML with abbreviations) or 'rss-1.0' (RSS 1.0, also an RDF/XML syntax).

The list of serializers depends on how libraptor(3) was built. The list of supported serializers is given in the help summary given by -h.

-O, --output-uri URI

Set the output/serializer base URI or use value '-' for no base. The default is the input base uri, either set by the argument INPUT-BASE-URI or via options -I, --input-uri URI

-c, --count

Only count the triples and produce no other output.

-e, --ignore-errors

Ignore errors, do not emit the messages and try to continue parsing.

-f, --feature FEATURE[=VALUE]

Set a parser or serializer feature FEATURE to a value, or to 1 if VALUE is omitted, Use -f help to get lists of valid parser and serializer features.

If the form -f 'xmlns:prefix="uri"' is used, the prefix and namespace uri given will be set for serializing. The syntax matches XML in that either or both of prefix or uri can be omitted.

-g, --guess

Guess the parser to use from the source-URI rather than use the -i FORMAT.

-q, --quiet

No extra information messages.

-r, --replace-newlines

Replace newlines in multi-line literals with spaces.


Print graph names (URIs) as they are seen in the input. This only has a meaning for parsers that support graph names such as the TRiG parser.


Print namespaces as they are seen in the input.

-t, --trace

Print URIs retrieved during parsing. Especially useful for monitoring what the guess and GRDDL parsers are doing.

-w, --ignore-warnings

Ignore warnings, do not emit the messages.

-v, --version

Print the raptor version and exit.


rapper -q -i ntriples -o rdfxml -f 'xmlns:rss=""' -f 'xmlns:ex=""' tests/test.nt
rapper -q -o rdfxml -f 'xmlns:rdfs=""' tests/rdf-schema.rdf ''


RDF/XML Syntax (Revised), W3C Recommendation,

N-Triples, in RDF Test Cases, Jan Grant and Dave Beckett (eds.), W3C Recommendation,

Turtle Terse RDF Triple Language, Dave Beckett,

RDFA in XHTML: Syntax and Processing, Ben Adida, Mark Birbeck, Shane McCarron and Steven Pemberton (eds.), W3C Candidate Recommendation, 20 June 2008

RDF Site Summary (RSS) 1.0, 2000-12-06



Removed -a option that did nothing.

Removed -m option from rapper but it was never documented here.

Removed -n option that was long hidden.

Removed -s option that was equivalent to -f scanForRDF


Added -I/--input-uri and -O/--output-uri to set the input and output (parser and serializer) base URIs separately.


Added -t/--trace to do URI traces.


Updated to add serializer rdfxml-abbrev


Updated potential parser and serializers and described -f for defining namespaces.


Added -f for features.
Added -g for guessing the parser to use.


Removed -a, --assume since rdf:RDF is now always optional.


libraptor(3) raptor-config(1)


Dave Beckett -

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