13.12 Writing to Multiple Terminals for Demonstrations

To show what one person is typing, and let people watch at other terminals:

1. The person doing the demonstration starts an interactive shell with a command like:

   % csh -i |& tee /tmp/log
   $ csh -i 2>&1 | tee /tmp/log

   Use exit to leave the shell. To start a Bourne shell, type sh instead of csh.

2. Everyone who wants to watch types:

   tail -f	tail -f /tmp/log

   and uses CTRL-c to kill tail-f when they're done.

There are a couple of gotchas:

• The person who's doing the demonstration won't be able to use full-screen programs like vi that expect their outputs to go to a terminal (instead of a pipe).

• Commands may echo onto the screen but not into the log file. If that happens, type csh -iv to start the demonstrator's C shell or sh -iv for a Bourne shell.