loggerfs is a FUSE-based virtual file system that automatically parses log files and sends that information to a MySQL or PostgreSQL database. Existing log parsers usually run periodically and scan the entire file for changes. loggerfs takes a different approach by providing a virtual file system. Whenever data is appended to a virtual file by the logging daemon, the information is directly stored in the database. There is no need to poll the file and monitor for changes.
Freedup finds and eliminates duplicate files by linking them, and thus reduces the amount of used disk space within one or more file systems. By default, hardlinks are used on a single device, symbolic links when the devices differ. A set of options allows you to modify the methods of file comparison, the hash functions, the linking behavior, and the reporting style. You may use batch or interactive mode. Freedup usually only considers identical files, but when comparing audio or graphics files, you may elect to ignore the tags.
trash-cli is a command line interface to the FreeDesktop.org trashcan. It implements the FreeDesktop.org trash specification. For each trashed file, it will remember the name, original path, date of deletion, and permissions. It interoperates with KDE and GNOME Trash, and is CLI compatible with the rm command.
Chiron FS is a FUSE based filesystem that implements replication at the filesystem level like RAID 1 does at the device level. The replicated filesystem may be of any kind you want; the only requisite is that you mount it. There is no need for special configuration files; the setup is as simple as one mount command (or one line in fstab).