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| Chapter 13 Redirecting Input and Output |

## 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.

- JP

13.11 tpipe-Redirecting stdout to More than One Place |  | 13.13 The "Filename" -