should save log file always.
more things should be logged.
added an exit in case the sorting script can't be found.
added a bit more feedback
Oops, moved the usage line to the wrong place.
More flags to check that things are okay.
Shouldn't process blank records at all.
adding BSD 3-clause license
Merge pull request #5 from daisieh/master

Added a lot more hooks to catch problematic files in the prepare_files script.