dirname() is a slow function compared with __DIR__ and using
'/../'. Moodle has a large number of legacy files that are included
each time a page loads and is not able to use an autoloader as it is
functional code. This allows those required includes to perform as
best as possible in this situation.
Useful for backing up a single course. Accepts parameters:
--courseid=INTEGER Course ID for backup
--courseshortname=STRING Course shortname for backup.
--destination=STRING Path where to store backup file. If not set, the backup
will stored within the same course backup area.
Tomo Tsuyuki