Parsley is described as 'A file synchronization tool with many configuration options and customizing interfaces' and is an app in the Backup & Sync category. There are six alternatives to Parsley for a variety of platforms, including Mac, Linux, Windows, BSD and openSUSE. The best alternative is FreeFileSync, which is both free and Open Source. Other great apps like Parsley are rsync (Free, Open Source), Unison (Free, Open Source), Truck - Rsync Client (Paid) and RsyncOSX (Free, Open Source).
A graphical user interface for rsync, which looks-and-feels like a standard FTP client, but uses the rsync protocol ‘under the hood’ to boost transfer speeds. In technical terms, it’s an SSH browser with an rsync transfer engine.
Lsyncd watches a local directory trees event monitor interface (inotify or fsevents). It aggregates and combines events for a few seconds and then spawns one (or more) process(es) to synchronize the changes. By default this is rsync.