=head1 NAME

nbdkit-bzip2-filter - decompress a .bz2 file

=head1 SYNOPSIS

 nbdkit file --filter=bzip2 FILENAME.bz2

=head1 DESCRIPTION

C<nbdkit-bzip2-filter> is a filter for L<nbdkit(1)> which transparently
decompresses a bzip2-compressed file.  You can place this filter on top
of L<nbdkit-file-plugin(1)> to decompress a local F<.bz2> file.

The filter only allows read-only connections.

B<Note> that bzip2 files are not very good for random access in large
files because seeking to a position in the bzip2 file involves
decompressing all data before that point in the file.  A more
practical method to compress large disk images is to use L<xz(1)>
or L<plzip(1)>.  Both L<nbdkit-xz-filter(1)> and L<nbdkit-lzip-filter(1)>
support block-level decompression if the file was compressed using the
right options.

To allow seeking this filter has to keep the contents of the complete
uncompressed file, which it does in a hidden temporary file under
C<$TMPDIR>.

=head1 PARAMETERS

There are no parameters specific to this filter.

=head1 ENVIRONMENT VARIABLES

=over 4

=item C<TMPDIR>

Because the bzip2 format is not seekable, this filter has to store the
complete contents of the compressed file in a temporary file located
in F</var/tmp> by default.  You can override this location by setting
the C<TMPDIR> environment variable before starting nbdkit.

=back

=head1 FILES

=over 4

=item F<$filterdir/nbdkit-bzip2-filter.so>

The plugin.

Use C<nbdkit --dump-config> to find the location of C<$filterdir>.

=back

=head1 VERSION

C<nbdkit-bzip2-filter> first appeared in nbdkit 1.40.  It is derived
from the C<nbdkit-gzip-filter> which first appeared in nbdkit 1.22.

=head1 SEE ALSO

L<nbdkit-file-plugin(1)>,
L<nbdkit-gzip-filter(1)>,
L<nbdkit-lzip-filter(1)>,
L<nbdkit-tar-filter(1)>,
L<nbdkit-xz-filter(1)>,
L<nbdkit(1)>,
L<nbdkit-plugin(3)>.

=head1 AUTHORS

Georg Pfuetzenreuter
Richard W.M. Jones

=head1 COPYRIGHT

Copyright Georg Pfuetzenreuter
Copyright Red Hat
