basically they unlink a package before linking the pack in place, which is almost fatal in case of busybox, and makes butch itself disfunctional during the operation.

so the command should probably refrain from doing the unlink action if the no_unlink tag is given, as other commands do too.

(in the case of unlinking busybox, the system can be restored by using the existing busybox binary in /opt/busybox/bin to restore /bin/busybox and /bin/sh, and then setting PATH to /opt/busybox/bin and running butch relink busybox)