Currently, by default, the mirror application
will remove all artifacts/installable units from a target repository before
preforming the mirroring. This can be avoided by using the "-append"
After some discussion we've decided
that the application should append by default. The problem we're now having
is deciding on what argument should be used to denote that the target repository
should remove all its content before the mirroring.
Arguments like "-delete" or
"-overwrite" aren't suitable because users may expect these arguments
to replace the entire repository, where as in reality only the content
will be replaced and any properties the target repository may have will
Please see the bug report at https://bugs.eclipse.org/bugs/show_bug.cgi?id=254747