Instead of waiting for long commands to finish one can easily get notifications when they are complete. The following procdure shows how to set his in fish shell.

Requirements: fish shell, notify-send, xdotool

• Add a new file vi ~/.config/fish/functions/noti.fish with the content below:

function fish_right_prompt
    if test $CMD_DURATION
        # Check if terminal window is hidden
        if test (xdotool getactivewindow) -ne $WINDOWID
            # Show notification if dration is more than 30 seconds
            if test $CMD_DURATION -gt 30000
                # Show duration of the last command in seconds
                set duration (echo "$CMD_DURATION 1000" | awk '{printf "%.3fs", $1 / $2}')
                notify-send (echo (history | head -1) returned $status after $duration)
            end
        end
    end
end

• Add the following line at the end of ~/.config/fish/config.fish to source noti.fish:

. ~/.config/fish/functions/noti.fish