Enter command mode
misc
// what it does
Presses the prefix (Ctrl+b by default) then `:` to open the tmux command prompt at the bottom of the screen. From here you type any tmux command directly — `split-window`, `set -g mouse on`, `kill-session` — without needing a bound key. It's the interactive equivalent of running `tmux <command>` from a shell, but it acts on the current client.
// shortcut
Ctrl + b:
// gotcha
Command-prompt line editing follows `status-keys` (default emacs) — separate from copy-mode's `mode-keys`. Up arrow recalls previous commands. If you set `status-keys vi`, Escape enters normal mode instead of cancelling the prompt.