Scenario: Something forces a reboot. I've got 4 bash shells open. I've been doing some compilation & linking of libraries with a crazy long gcc command. After I reboot, that's not in my history because only the first-opened bash shell's history seems to get saved and I've gotta recreate the commandline again. Is there any shell that would let me see all the history from all of the different shells I might have had open?
I had something similar set up on my second to last work laptop. I had done some heavy customization that was mostly focused on common workflows for that job, but I have learned that I should still keep a backup even if most of it won't work elsewhere. I should have learned this lesson almost a couple decades ago when I lost all my emacs customizations on a personal computer. But instead, I decided to learn vim.
As unhelpful as the other commenter suggesting atuin was, this is actually a thing that atuin does well, if you're using a shell it supports, it commits to history immediately.