procmail recipe spawning shell, appending message

        i have the following procmail recipe, taken from someone
on this list, i think, to add a Content-Type header to incoming
PGP-encrypted mail.  any mail that actually matches it, however,
ends up spawning a shell; my .zshenv prints a greeting message,
which then becomes the first line of the message, and the From_
line gets escaped by a >.  the end result is that any PGP-signed
message gets appended to the last message in its appropriate mailbox,
rather than being filed as a message of its own; checking the
procmail logs shows an error message produced by .zshenv, in addition
to the normal delivery.
        any idea what's going wrong here?

        tia,
        sweth.

      # Add a "Content-Type: application/pgp" header so Mutt will know the
      # mail is encrypted.
      :0 fBw
      * ^-----BEGIN PGP MESSAGE-----
      | formail -a "Content-Type: application/pgp; format=text; 
x-action=encryptsign"

      # Add a "Content-Type: application/pgp" header so Mutt will know the
      # mail is signed.
      :0 fBw
      * ^-----BEGIN PGP SIGNED MESSAGE-----
      | formail -a "Content-Type: application/pgp; format=text; x-action=sign"


-- 
Sweth Chandramouli
IS Coordinator, The George Washington University
<sweth(_at_)gwu(_dot_)edu> / (202) 994 - 8521 (V) / (202) 994 - 0458 (F)
<a href="http://astaroth.nit.gwu.edu/~sweth/disc.html";>*</a>