This information pertains mainly to OtsJuke DJ version 1.0.53 and above. Some of the command line options explained here have been present since the very first version, but some have not, and some have changed in their precise behaviour. It is best to run the latest version of OtsJuke.
All options are case-insensitive.
First, let's discuss the file arguments. This database is memory based, not disk based, therefore it is always empty when you first start OtsJuke, which is why you would use this option to import your collection. Alternatively, the first file argument may be an OTS file or an ASC file. If the first file argument is a folder, you may specify a second file argument also, which may be an ASC or OJL file. This functionality is available because it would not make sense to specify a OJL file as the only file argument, since this file format relies on each referenced item having been already being imported into the database.