.\" Copyright 2011-2023 David Robillard <d@drobilla.net>
.\" SPDX-License-Identifier: ISC
.Dd May 04, 2023
.Dt SERD-PIPE 1
.Os Serd 1.1.1
.Sh NAME
.Nm serd-pipe
.Nd read and write RDF data
.Sh SYNOPSIS
.Nm serd-pipe
.Op Fl abefhlqtv
.Op Fl B Ar base
.Op Fl c Ar prefix
.Op Fl i Ar syntax
.Op Fl k Ar bytes
.Op Fl o Ar syntax
.Op Fl p Ar prefix
.Op Fl r Ar root
.Op Fl s Ar string
.Op Ar input ...
.Sh DESCRIPTION
.Nm
is a fast command-line utility for streaming and processing RDF data.
It reads one or more RDF documents and writes the data to stdout,
possibly transformed and/or in a different syntax.
By default,
the input syntax is guessed from the file extension,
and output is written in NTriples or NQuads.
.Pp
.Nm
can be used to check for syntax errors,
convert from one syntax to another,
pretty-print documents,
or transform URIs and blank node IDs.
.Pp
The options are as follows:
.Bl -tag -width 3n
.It Fl B Ar base
Input base URI.
Relative URI references in the input will be resolved against this.
When the input is a file,
the URI of the file is automatically used as the base URI.
This option can be used to override that,
or to provide a base URI for input from stdin or a string.
.It Fl a
Write ASCII output.
If this is enabled, all non-ASCII characters will be escaped, even if the output syntax allows them to be written in UTF-8.
.It Fl b
Bulk output writing.
If this is enabled, output will be written a page at a time, rather than a byte at a time.
.It Fl c Ar prefix
Chop
.Ar prefix
from matching blank node IDs.
This is typically used to revert the effects of
.Fl p .
For example, with
.Ar prefix
.Dq doc01 ,
the blank node
.Li _:doc01b42
will be emitted as
.Li _:b42 .
.It Fl e
Eat input one character at a time, rather than a page at a time which is the default.
This is useful when reading from a pipe since output will be generated immediately as input arrives, rather than waiting until an entire page of input has arrived.
With this option one less page of memory is used, but likely with a performance penalty.
.It Fl f
Fast and loose URI mode:
preserve full URIs (without qualifying or making relative),
and pass prefixed names through as-is.
.It Fl h
Print the command line options.
.It Fl i Ar syntax
Read input as
.Ar syntax .
Case is ignored, valid values are:
.Dq NQuads ,
.Dq NTriples ,
.Dq TriG ,
and
.Dq Turtle .
.It Fl k Ar bytes
Parser stack size.
Parsing is performed using a pre-allocated stack for performance and security reasons.
By default, the stack is 1 MiB, which should be sufficient for most data.
This can be increased to support unusually structured data and huge literals,
or decreased to reduce overall memory requirements and reduce startup time.
.It Fl l
Lax (non-strict) parsing.
If this is enabled, recoverable syntax errors will print a warning, but parsing will proceed starting at the next statement if possible.
Note that data may be lost when using this option.
.It Fl o Ar syntax
Write output as
.Ar syntax .
Case is ignored, valid values are:
.Dq empty ,
.Dq NQuads ,
.Dq NTriples ,
.Dq TriG ,
and
.Dq Turtle .
The
.Cm empty
syntax suppresses the output,
so that only warnings and errors will be printed.
.It Fl p Ar prefix
Add
.Ar prefix
to blank node IDs.
This can be used to avoid clashes between blank node IDs in input documents.
The effects can be reversed in a later run with
.Fl c .
For example, with
.Ar prefix
.Dq doc01 ,
the blank node
.Li _:b42
will be emitted as
.Li _:doc01b42 .
.It Fl q
Suppress all output except data.
.It Fl r Ar root
Keep relative URIs within a
.Ar root
URI.
This will avoid creating any relative URI references with leading path segments like
.Pa ../
that enter a parent of
.Ar root .
.Pp
For example,
if
.Pa /home/you/file.ttl
is written to the file
.Pa /home/me/output.ttl
using the destination's base URI,
then it could be written as
.Li <../you/file.ttl> .
Setting
.Fl r Li file:///home/me/
would prevent references from
.Dq escaping
like this,
so the above would instead be written as
.Li <file:///home/you/file.ttl> ,
since it can't be expressed relative to the root URI.
.Pp
This is useful for keeping relative references within some directory.
.It Fl s Ar string
Parse
.Ar string
as input.
.It Fl t
Write terser output without newlines.
.It Fl v
Display version information and exit.
.El
.Sh EXIT STATUS
.Nm
exits with a status of 0, or non-zero if an error occurred.
.Sh EXAMPLES
.Bl -tag -width 3n
.It Pretty-print a document:
.Nm Fl o
.Ar turtle
.Pa file.ttl
>
.Pa out.ttl
.It Print only errors and discard the output:
.Nm Fl O
.Ar empty
.Pa input.ttl
.El
.Sh SEE ALSO
.Bl -item -compact
.It
.Lk http://drobilla.net/software/serd/
.It
.Lk http://gitlab.com/drobilla/serd/
.El
.Sh STANDARDS
.Bl -item
.It
.Rs
.%A W3C
.%T RDF 1.1 NQuads
.%D February 2014
.Re
.Lk https://www.w3.org/TR/n-quads/
.It
.Rs
.%A W3C
.%D February 2014
.%T RDF 1.1 NTriples
.Re
.Lk https://www.w3.org/TR/n-triples/
.It
.Rs
.%A W3C
.%T RDF 1.1 TriG
.%D February 2014
.Re
.Lk https://www.w3.org/TR/trig/
.It
.Rs
.%A W3C
.%D February 2014
.%T RDF 1.1 Turtle
.Re
.Lk https://www.w3.org/TR/turtle/
.El
.Sh AUTHORS
.Nm
is a part of serd, by
.An David Robillard
.Mt d@drobilla.net .