You've conflated terminal and shell there. It's an important distinction because, in fact, there's still one race condition with history files, even if you onl

You've conflated terminal and shell there. It's an important distinction because, in fact, there's still one race condition with history files, even if you only have /one/ shell running. It's down to the Bourne Again shell not doing atomic updates when it rewrites the history file. It's one of two bugs, the other being systemd sending multiple signals in very quick succession to kill a terminal login session, that in combination cause the effect discussed at https://news.ycombinator.com/item?id=10151861 https://news.ycombinator.com/item?id=10151861 . Far from losing zero or a few history elements, it can in fact result in your losing all of your history.