Poppins is described as 'command line utility, written in PHP, which takes copies from remote Unix based systems. Optionally it can also backup MySQL databases. The data are stored on a file system, in incremental snapshots. All network transfers are encrypted with SSH' and is an app in the Backup & Sync category. There are three alternatives to Poppins for Linux, Mac and Windows. The best alternative is Déjà Dup, which is both free and Open Source. Other great apps like Poppins are Duplicity (Free, Open Source) and rdiff-backup (Free, Open Source).
rdiff-backup backs up one directory to another, possibly over a network. The target directory ends up a copy of the source directory, but extra reverse diffs are stored in a special subdirectory of that target directory, so you can still recover files lost some time ago.