CONTROL MODE
     tmux offers a textual interface called control mode.  This allows
     applications to communicate with tmux using a simple text-only protocol.

     In control mode, a client sends tmux commands or command sequences
     terminated by newlines on standard input.  Each command will produce one
     block of output on standard output.  An output block consists of a %begin
     line followed by the output (which may be empty).  The output block ends
     with a %end or %error.  %begin and matching %end or %error have two
     arguments: an integer time (as seconds from epoch) and command number.
     For example:

           %begin 1363006971 2
           0: ksh* (1 panes) [80x24] [layout b25f,80x24,0,0,2] @2 (active)
           %end 1363006971 2

     The refresh-client -C command may be used to set the size of a client in
     control mode.

     In control mode, tmux outputs notifications.  A notification will never
     occur inside an output block.

tmux new -s mysession

tmux -C attach -t mysession

%layout-change @2 91a8,80x23,0,0[80x11,0,0,5,80x11,0,12,7]
%window-add @3
%window-close @1

tmux -C attach