ISEA - Interactive Server Eval At
Emacs can run as a daemon.
Emacs can run multiple daemons each with a different socket.
Emacs can talk from one daemon to another, quite easily, using the server-eval-at function.
This is a shell to let you talk to a particular Emacs daemon in a simple way.
Obligatory Early Code Warning
This code could hang your Emacs!
I make no promise about whether we've caught everything that could hang the terminal or the client process.
But I'd also like to point out how amusing it is that we worry about whether we'll have to restart our Emacsen. Uptime competitions are important!