A name, like /usr/bin/editor, which refers, via the alternatives system, to one of a number of files of similar function.
Without any further qualification, this means a symbolic link in the alternatives directory: one which the system administrator is expected to adjust.
The name of a specific file in the filesystem, which may be made accessible via a generic name using the alternatives system.
A directory, by default /etc/alternatives, containing the symlinks.
A directory, by default /var/lib/alternatives, containing alternatives' state information.
A set of related symlinks, intended to be updated as a group.
The link in a link group which determines how the other links in the group are configured.
A link in a link group which is controlled by the setting of the master link.
When a link group is in automatic mode, the alternatives system ensures that the links in the group point to the highest priority alternatives appropriate for the group.
When a link group is in manual mode, the alternatives system will not make any changes to the system administrator's settings.
--set name path
The symbolic link and slaves for link group name set to those configured for path, and the link group is set to manual mode. This option is not in the original Debian implementation.
I'm still reading this. I might understand it tomorrow.
EDIT: If you need to create a custom link-group for each NEW individual usplash-custom-cool-theme.so, then what is update-usplash-theme FOR? Just to revert to the default theme??
EDIT: I'm in over my head. Just if you can explain this then that would be great. But I would also like to know what the update-usplash-theme script is and how to use that as well.