quickly cycle between last pane across all windows of a session. also add a little flash when changing focus to a new pane.

tmux_panefocus.sh

#!/bin/bash

## about

# this does two things 1) provides a visual indicator when moving between panes
# 2) cleverly cycles between the previous pane on all windows across the session.
# NOTE this script does echo out every single tmux focus switch to a file in /tmp/
# so unless you turn your machine off every night you'll want to find some way of
# dealing with that.


#       ## add to ~/.config/tmux/tmux.conf
#
#       ## clever switching to last pane or window in session
#       bind -n C-Tab run-shell "~/.local/bin/tmux_panefocus.sh --focuslast"
#
#       ## enable focus hooks
#       set -g focus-events on
#
#       ## flashes pane and echoes out current pane for clever focus switching.
#       set-hook -g pane-focus-in 'run-shell "~/.local/bin/tmux_panefocus.sh --onfocus"'


## pick a color
flashcolor="#121201"
current=$(tmux display-message -p "#{session_id} #{window_id}.#{pane_id}")

case $1 in
    --onfocus)
        ## compare with last line in hist
        prev=$(cat /tmp/tmuxpanehist | tail -n 1)

        ## to prevent flashing pane when moving from outside tmux, or if there's only one pane
        if ! [[ ${current} == ${prev} ]] && [[ $(tmux list-panes | wc -l) -gt 1 ]]; then
            ## make the pane flash
            tmux selectp -P bg=${flashcolor}
            sleep 0.1
            tmux selectp -P bg=default
        fi

        ## echo out the pane details to temp file
        echo "$current" >> /tmp/tmuxpanehist
        ;;

    --focuslast)
        ## take current details as variable
        current=$(tmux display-message -p "#{session_id} #{window_id}.#{pane_id}")
        current_session=${current%% *}
        current_windowpane=${current##* }
        current_window=${current_windowpane%%.*}
        current_pane=${current_windowpane##*.}
        ## half of these aren't needed but i won't need to look up substring manipulation
        ## if i decide to change something.

        ## check tempfile for current session, filtering out dupes
        prev=$(grep ${current_session} /tmp/tmuxpanehist | grep -v "${current_windowpane}" | tail -n 1)
        if [[ $prev == "" ]]; then
            tmux display-message -d 5000 "no prev"
            exit
        fi
        prev_session=${prev%% *}
        prev_windowpane=${prev##* }
        prev_window=${prev_windowpane%%.*}
        prev_pane=${prev_windowpane##*.}

        ## check whether last pane is in current window
        ## TODO need to think of a better fallback if prev window has been closed
        if [[ ${current_window} == ${prev_window} ]]; then
            tmux select-pane -Z -t "${prev_window}.${prev_pane}" || tmux select-pane -t :.- -Z
        else
            ## if not switch window first
            tmux select-window -t "${prev_window}" || tmux select-pane -t :.- -Z
            tmux select-pane -Z -t "${prev_pane}" || tmux select-pane -t :.- -Z
        fi
        ;;
esac