Formail

Finally, intelligent processing

Formail is the mail (re)formatter. With it you can add or extract headers, generate auto-reply headers, do digest extraction, etc. Here is where the magic really begins.

You must completely read the formail manpage to understand it's operation Let's start with a simple example from my own .procmailrc. I recently left UIUC and my email address used to be <jgross@uiuc.edu>. I knew my old address would go away at some point so I got a new one at <jgross@stimpy.net>.

I didn't want to lose the mail that people were sending to jgross@uiuc.edu and I also wanted to mail them a reminder that my ph alias had changed. Formail comes to the rescue:

# This recipe will take any mail addressed to jgross@uiuc.edu and create an autoreply
# header. The autoreply header will have a To: that is set to the sender of the mail.
# We then extract the To: header and append it to the $HOME/.uiucers file so we have
# a list of who's been using the old address.

# The -r means get a return address. The -x means extract a header.

:0c
* ^TOjgross@uiuc.edu
{
	:0c
	|formail -r -x "To:" >> $HOME/.uiucers


	# This next part will send them a letter containing .uiuc.message which
        # tells them I got the letter but to start using jgross@stimpy.net as my address
	# The -brt essentially generates an autoreply header.
	# I use the -I to add the "correct" From: header
	# We then append the .uiuc.message as they body and pipe it through sendmail.
	# We also use a backslash to span a line break
	# This really does do a lot so don't try to swallow it whole.
	:0
	| (formail -brt  -I 'From: Joe Gross <jgross@stimpy.net>' ; \
 	   cat $HOME/.pick.message) | $SENDMAIL -t
}

Don't worry too much about this. You'll get the hang of formail as we go through other (probabaly simpler) examples.

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