How can I make all tmux panes have their own unique shell history?

Question

Preface: My current tmux configuration has multiple panes in multiple windows in multiple sessions.

The problem that keeps arising is that when I work in one window, all my history is good and separate between that window's panes, and when I swap windows/sessions, that history is initially separate too, but only until I enter one command in a different window/session.

Once that happens, all the history for all panes gets merged together and it's sometimes impossible to find a certain pane's actual last command, depending on how long it had been since I was on the pane.

Is there any way to avoid this and have each pane have its own shell history?

Answer 1

If you're using the bash shell, your command history is written to a file defined by the HISTFILE variable, which defaults to ~/.bash_history. Inside a tmux pane, you have access to the variable $TMUX_PANE which looks something like this:

$ echo $TMUX_PANE
%3

You could use this to create a per-pane history by adding something like this to your ~/.bashrc file:

if [[ $TMUX_PANE ]]; then
  HISTFILE=$HOME/.bash_history_tmux_${TMUX_PANE:1}
fi

This will store the history for pane 2, for example, in ~/.bash_history_tmux_2.

The downside to this idea is that you're going to end up with a bunch of .bash_history_tmux_* files in your home directory.