procmailrc for format conversion

foo.procmailrc

# Convert old-style inline PGP messages to MIME
:0
* !^Content-Type: message/
* !^Content-Type: multipart/
* !^Content-Type: application/pgp
{
    :0 fBw
    * ^-----BEGIN PGP MESSAGE-----
    * ^-----END PGP MESSAGE-----
    | formail \
    -i "Content-Type: application/pgp; format=text; x-action=encrypt"

    :0 fBw
    * ^-----BEGIN PGP SIGNED MESSAGE-----
    * ^-----BEGIN PGP SIGNATURE-----
    * ^-----END PGP SIGNATURE-----
    | formail \
    -i "Content-Type: application/pgp; format=text; x-action=sign"
}

# Preconverts all plain-text mail arriving in certain encoded
# MIME formats into a more compact 8-bit format which can be
# used and displayed more easily by most programs.
:0
* ^Content-Type: *text/plain
{
    :0 fbw
    * ^Content-Transfer-Encoding: *quoted-printable
    | mimencode -u -q

    :0 Afhw
    | $FORMAIL -I "Content-Transfer-Encoding: 8bit"

    :0 fbw
    * ^Content-Transfer-Encoding: *base64
    | mimencode -u -b

    :0 Afhw
    | $FORMAIL -I "Content-Transfer-Encoding: 8bit"
}