Q:

Send a keyboard shortcut to all of the panes for the current tmux session

I have some panes opened in tmux window. In all panes started performs some commands/programs. And I need to close all of them. Of course, I can manually switch to each pane and press Ctrl+C. However, it is to long. Is there some way of some sort of multicast the shortcut to all of the tmux panes?

A:

There is a command in tmux, that lets send any commands/shortcuts to all of the panes: 
PREFIX:setw synchronize-panes
PREFIX is a standard keyboard shortcut activates tmux. It's CtrlB in my tmux (other have CtrlA, for example)
Actually, I bind a couple of keyboard shortcuts in ~/.tmux-conf to switch on/off panes synchronization:
bind e setw synchronize-panes on
bind E setw synchronize-panes off

