Signatures 'n' stuff

[Mike Hicks <hick0088@tc.umn.edu>]

Carl Wilhelm Soderstrom wrote:
>
>         I see that you're using Netscrape:
> X-Mailer: Mozilla 4.7 [en] (X11; U; Linux 2.2.14 i586)
> 
> how do you call your program from within it? or do you just call it
> separately and paste the .sig in?

I forgot to mention that.  Unix has the capability to have a 'named
pipe'.  It appears to be a file, but in order to read it, you need to
have another program putting data into the pipe.  On my computer, my
.signature file is actually a named pipe (you can do the same by running
the command 'mknod .signature p'), and the signature generator runs in a
continuous loop, outputting a new signature each time the pipe is read. 

The simple example of this would be something like (this should be
roughly chronological input/output..)

  Terminal 1                    Terminal 2
$ mknod .signature p
$ echo hello > .signature
 <terminal appears frozen>    $ cat .signature
 <terminal un-freezes>        hello
$                             $

You should be careful about named pipes, though, as a mailer trying to
read a .signature file that is not getting any input will freeze up
(also, some system administrators re-compile programs like pine to
prevent users from using named pipes -- finger used to have this same
ability to read your .plan file as a named pipe, but it tured out to be
a big security problem).

-- 
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/ \/ \(_)| ' // ._\  / - \(_)/ ./| ' /(__   Jesse Berst 
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 [ Mike Hicks | http://umn.edu/~hick0088/ | mailto:hick0088@umn.edu ]