Forcing a linkback

When oneSIS creates the linkback symlinks at boot time, it normally checks to make sure that the symlink target actually exists in the master image first. If the target does not exist, the linkback ends up pointing back to the `.default' for the specified file.

However, the linkback can be forced even if the target doesn't exist. Using the -f flag of the LINKBACK directive will cause the link back to the target to be created even if the target doesn't exist at boot time.

Since oneSIS creates these links before any other system initialization is done, remote filesystems specified in /etc/fstab are typically not mounted yet. The -f flag can be especially useful to point to locations on a network filesystem that have not been mounted yet.