histbackup

histbackup makes incremental backups of a directory tree in a set of directories named by dates, or date-time if the date already exists. Its companion script histbackup-prune controls the archive growth. The new backup is prepopulated by hardlinks of each file from the previous backup and then updated with rsync(1). This arranges that the only new content of each new backup is fresh copies of the changed files. In this way each backup directory is a full copy of the source directory but the disk space cost is that of an incremental backup. Because it uses rsync, it is possible to efficiently backup remote directories in this manner.