Re: how do I "change field only if it exists"

>  I need to detect "Content-Transfer-Encoding: quoted-printable" field, and
> it the field exists, replace the content of with my new content
> Content-Transfer-Encoding: 8BIT
>  and if the field Content-Transfer-Encoding doesn't exist, don't add the
> field ? How do I do it with formail ?
Read "procmailex".  Here is an excerpt:

       The following  example  preconverts  all  plain-text  mail
       arriving  in certain encoded MIME formats into a more com-
       pact 8-bit format which can be  used  and  displayed  more
       easily by most programs.  The mimencode(1) program is part
       of Nathaniel Borenstein's metamail package.

              :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"
              }