There are many questions with similar wording regarding how to save commands before exiting the session which answer something else (PROMPT_COMMAND='history -a'
, histopt
etc.).
This question has a misleading wording, for instance, but talks about not fully typed commands instead.
I am asking about an earlier trigger for bash auto-saving a command. For example, I need to see from another terminal a history already including any command with unfinished execution.
I suspect bash implementation won't be able to do that directly. However I think it worth asking.