Parity Archive Volume Set, for checking and repair of files

 A command line implementation of the PAR v2.0 specification. This
 specification is used for parity checking and repair of a file set.
 If the files in the recovery set ever get damaged (e.g. when they are
 transmitted or stored on a faulty disk) the client can read the damaged
 input files, read the (possibly damaged) PAR files, and regenerate the
 original input files. Of course, not all damages can be repaired, but
 many can.