I need to extract some message/rfc822 mime sections from the emails and I want to know if I archieve something like this in maildropfilter:

if ((cat my_mail | reformime -s 1.2 -i | grep message/rfc822) -eq message/rfc822) then cat my_mail | reformime -e 1.2 | sa-learn --ham

So what i need to do is pipe my mail through reformime and grep and check the return value and if true do execute sa-lean and if not skip and increment 1.2 to 1.3 in the reformime statement.

As far as I see in the man page if I call xfilters my mail would be replaced by the return value of grep. And when I call " to | program " I have to write that logic in that program itself.