=head1 NAME

botch-graph-sources - find all sources (vertices without predecessors) in a graph in GraphML or dot format

=head1 SYNOPSIS

=over

=item B<botch-graph-sources> [options] [I<ingraph>] [I<outgraph>]

=back

=head1 DESCRIPTION

Extract the subgraph of all sources (vertices without predecessors) in the
input graph.

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<-v, --verbose>

Be verbose.

=back

=head1 EXAMPLE

Find all source packages that build depend on C<texlive-binaries:amd64 (=2015.20150524.37493-5)>.

Using package selection and reverse dependency cone computation by ceve:

	dose-ceve -r "texlive-binaries:amd64 (= 2015.20150524.37493-5)" --deb-native-arch=amd64 -G pkg -T grml deb://Packages debsrc://Sources \
		| botch-graph-sources - - \
		| botch-graph2text - "{realpackage} (= {realversion})" --vertex type:src \
		| sort

Using package selection and ancestor vertex computation by botch:

	dose-ceve --deb-native-arch=amd64 -G pkg -T grml deb://Packages debsrc://Sources \
		| botch-graph-ancestors - - --target realpackage:texlive-binaries:amd64 realversion:2015.20150524.37493-5 \
		| botch-graph-sources - - \
		| botch-graph2text - "{realpackage} (= {realversion})" --vertex type:src \
		| sort

=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.

