=head1 NAME

botch-graph-descendants - find all descendants of a vertex in a graph in GraphML or dot format

=head1 SYNOPSIS

=over

=item B<botch-graph-descendants> [options] --source I<SOURCE> [--source I<SOURCE> ...] [I<ingraph>] [I<outgraph>]

=back

=head1 DESCRIPTION

Extract the subgraph of all descendants of a specific node in the input graph.

The B<--source> option is mandatory and can be specified more than once.

If either (or both) of the positional arguments is/are omitted, then read
GraphML or dot from standard input and/or write GraphML or dot to standard
output, respectively.  Passing a '-' as either argument, explicitly specifies
to read the input from standard input and write the output to standard output,
respectively.

The input graph type will be determined automatically. If the output graph is
given as a filename, then the output type will be GraphML if the filename ends
with .xml and dot if the filename ends with .dot. If the output is done on
standard output then it will happen in the same format as the input graph.

=head1 OPTIONS

=over 4

=item B<-h, --help>

Display help.

=item B<--source=>I<SOURCE>

This option picks the source vertex of which the descendants are computed. The
SOURCE argument is a key/value pair (separated by a colon) of a graph attribute
and its desired value. If more than one vertex matches the given key/value
pair, then the smallest (by node comparison) is chosen.

The special key C<__ID__> allows one to select the unique vertex identifier.

This option can be specified more than once. The final set of vertices is
chosen such that all vertices match all key/value pairs. Multiple B<--source>
options thus form a logical conjunction (they are AND-ed together).

=item B<-v, --verbose>

Be verbose.

=back

=head1 EXAMPLE

Extract the subgraph of all descendants of a binary packages vertex with name
"build-essential" and version "11.7".

  botch-graph-descendants --source name:build-essential --source version:11.7 --source type:bin < in.xml > out.xml

or giving input and output as positional arguments:

  botch-graph-descendants --source name:build-essential --source version:11.7 --source type:bin in.xml out.xml

=head1 BUGS

See L<http://bugs.debian.org/botch>.

=head1 SEE ALSO

Debian doc-base Manual F</usr/share/doc/botch/wiki/Home.html>

=head1 AUTHOR

This man page was written by Johannes Schauer. Botch is written by Johannes
Schauer and Pietro Abate.

=head1 COPYRIGHT

Copyright 2012-2014 Johannes Schauer, Pietro Abate

This program is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option) any
later version. A special linking exception to the GNU Lesser General Public
License applies to this library, see the COPYING file for more information.

