I don't pay enough attention to e-mail notifications any more, since I
no longer get alerts for them on my phone. I do get Matrix
notifications, though, through Element, and that seems to work well as a
reminder for me.
Matrix is of course a lot more complex than e-mail. It is a stateful
protocol that requires (at least) keeping authentication and/or session
information on the client. Technically, clients all have a "device ID,"
which they should use any time they communicate with the server. I
decided it makes the most sense to keep this value in the same cache
file as the filesystem UUIDs and timestamps. I prefer reading usernames
and passwords from a configuration file over passing them as
command-line arguments, so I added that ability as well.
If the UUID of the mounted filesystem is different than the cached UUID
for that filesystem, the cache needs to be updated with the new value.
Otherwise, the program will continually emit warnings once the cached
entry expires, regardless of whether or not the filesystem has changed
in that time.
Dustin