Backup apps come in all shapes and sizes, and your distro probably has one by default as B well. But if you need something that offers plenty of options through a graphical interface, take a look at FreeFileSync.
You can use this handy application to mirror the contents of two folders, as well as take backups, irrespective of whether they are housed in a local drive or a remote location.
Download the app’s CLI installer as a tarball from its website. Then extract it and fire up the installer with ./FreeFileSync_14.0_Install.run . By default, the installer installs the app for all users under the /opt/FreeFileSync directory, but you can alter any of these behaviours.
The app has a busy interface, but it’s well laid out. Begin by choosing left and right folders. You can then use the Compare button to compare the content of the two folders.
Next, comes the most important part – the synchronisation settings. By default, the app does a two-way sync, which means it makes sure both folders are exact replicas of each other by creating, updating and deleting files in both locations.