to restore.
Back In Time keeps multiple logs of actions and activities, file changes, and
versions, and it is a useful tool.
You can find the official documentation for Back In Time at
https://backintime.readthedocs.io/.
Unison
Unison is a file-synchronization tool that works on multiple platforms,
including Linux, other flavors of UNIX such as Solaris and macOS, and
Windows. After Unison is set up, it synchronizes files in both directions and
across platforms. If changes are made on both ends, files are updated in both
directions. When file conflicts arise, such as when the same file was modified
on each system, the user is prompted to decide what to do. Unison can
connect across a network using many protocols, including ssh. It can
connect with and synchronize many systems at the same time and even to the
cloud.
Unison was developed at the University of Pennsylvania as a research project
among several academics. It is no longer under active development as a
research project, but it does appear to continue to be maintained with bug
fixes and very occasional feature additions. The original developers claim to
still be using it daily, so it is not completely abandoned.
Unison is powerful and configurable. The foundation is based on rsync, but
with some additions that enable functionality that is generally available only
from a version control system. See Chapter 41, “Using Ubuntu for
Opportunistic Software Development,” for an introduction to these features,
as well as a brief mention later in this chapter in the context of backing up
configuration files.
Even though the project is no longer the primary focus of any of the
developers, many people still use Unison. For that reason, it gets a mention in
this chapter and might be worthy of your time and effort if you are interested.
Unison is released under the free GPL license, so you might decide you want
to dig in to the code. The developers have publicly stated that they do not
have time to maintain it regularly but welcome patches and contributions. If
this is a project that interests you, see www.cis.upenn.edu/~bcpierce/unison/.