libtmux:pipe-pane

Configure PANE's tmux-owned pipe and return a COMMAND-OUTCOME. SHELL-COMMAND is shell source, literal to tmux by default; FORMAT-P explicitly enables tmux format and time expansion before shell execution. DIRECTION is :OUTPUT (pane to shell), :INPUT (shell to pane), or :BOTH. Omit SHELL-COMMAND, or pass an empty string, to close the pipe. TOGGLE closes an existing pipe without starting its replacement. Replacing a pipe closes the previous one. Completion acknowledges configuration, not shell startup, success or output consumption. The daemon owns the pipe child; closing CLIENT leaves it running. Literal commands exceeding tmux's time-format capacity fail before I/O. Signals STALE-TARGET or an operational condition; never retries configuration.