For divers who use linux on their computers, now there is Subsurface opensource software
program. It works on Ubuntu 18.04
Information from the Software install…
Subsurface can plan and track single- and multi-tank dives using air, Nitrox
or TriMix. It allows tracking of dive locations including GPS coordinates
(which can also conveniently be entered using a map interface), logging of
equipment used and names of other divers, and lets users rate dives and
provide additional notes.