If that's your use case, here's another game changer (one line bashrc change to make bash_history changes immediately, rather than upon shell exit, e.g. when you end your tmux session): https://web.archive.org/web/20090815205011/http://www.cuberi...
"Ted, the change I suggest doesn't affect the independence of your sessions as you suggest. Each shell maintains a unique history in memory so modifying the history file has no affect on running terminals. The only time the history file is read is when you start a new terminal. I recommend you try my suggestion. Really, all I am doing is eliminating the race condition that causes the bash history file to have inconsistent data.
Thanks for the feedback."
If you do want to load the history persisted from other shells into the current one, all you have to do (if memory serves) is:
$ history -r setopt inc_append_historySo, you revisit a window, and you want to start from where you left, but now, you might maybe wade through 100's of commands before you get back to that point in time. There are fixes for this too of course, my point is, that it doesn't come without side effects, and that is maybe why it isn't set as default behaviour. At least in a pre 'fzf/atuin/smenu' world.
I prefer smenu's history search, even if I consider myself a heavy fzf user.
To wit:
> It says to put those commands in the .bashrc config:
shopt -s histappend
PROMPT_COMMAND="history -a;$PROMPT_COMMAND"
I used to have something like this set up on my Linux laptop - the downside is that seperate shell/terminals/windows/tabs don't keep seperate history - so if you eg start a server in shell one (rails s), start editor in two - then go back to one and ctrl-c out - up arrow will now give you "vim" not "rails s".
The problem compounds if you ping, or curl in another shell etc.
PROMPT_COMMAND='history -a'
Has always worked for me. Goes in your .bashrc from the FM
PROMPT_COMMAND ¶ If this variable is set, and is an array, the value of each set element is interpreted as a command to execute before printing the primary prompt ($PS1). If this is set but not an array variable, its value is used as a command to execute instead.