Due to some really buggy software that likes to write its own backup files to its working area even when that it disabled, duplicity has backed up those backups resulting in several hundred GBs of useless data in its archives (I use duplicity to automatically backup the working directory of this software each day, which, when the software doesn't listen when it is told to not also backup, results in backups being backed up, which is an explosion of disk space on the order of O(n²) or so.). All of the problematic files are in a single directory, /path/to/software's/working/directory/backups, and I need to get these backups out of duplicity's archives so I have some breathing room on my server's SSD before a month goes by and the backups expire. How can I do this, without affecting the rest of the actually useful data that duplicity is storing?
sorry, you can't. the best duplicity can do for you is a new full backup where you excluded mentioned folder.