Is it possible to make a "file" that can change its output when accessed?
 

I'm trying to get an email program that doesn't have a random signature feature to use random signatures. All it has is a place to specify a single file as the signature file. Specifying a shell script that will output a random signature doesn't work, I just get part of the shell script as my signature.

Is there some way to create something that will, when accessed as if it were a file, be able to generate different output?

Maybe have a cron job run a script which rotates/randomises where a link goes to on your harddrive, and have the email program use the link file as the sig.

I don't know what client you are using but have you tried things like adding backticks?

Here's what I do:
Check out:
Boris' Taglines
Then each time the tagline is called it generates a random quote into a .signature file, which is then called by my mail program (kmail) each time. Since the .signature file is randomly created each time the tagline is called, I just have to reference to that for my signature ;)

Cool

Thank you everybody!

I use pine, which allows pipes:

in ~/.pinerc:
~/.sigproc: