ken@Miranda ~/c/_/tmp
$ geo_file_join.pl
2010-10-01 00:00:03 lat1 long1 grav1 null null
2010-10-02 00:00:05 lat2 long2 grav2 mag1 null
2010-10-03 00:00:07 lat3 long3 grav3 mag2 bath1
2010-10-04 00:00:09 lat4 long4 null mag3 bath2
2010-10-05 00:00:01 lat3 long3 null null bath3