search for date received possible?

[Gregor Zattler]

Hi Ivy,
On Sun, 23 Oct 2011 12:47:41 -0400, Ivy Foster <joyfulgirl at archlinux.us> wrote:
> On Sun, 23 Oct 2011 16:53:29 +0200, Gregor Zattler <telegraph at gmx.net> wrote:
> > is it possible to limit searches to date received ranges
> > instead of date (sent) ranges?
> 
> If your mail is delivered by procmail, I know you can insert
> arbitrary headers as part of the mail-processing stage,
> generally using formail. Such a recipe could look something
> like this:
> 
>       NOW=$(date)
>       :0 fhw
>       | /usr/bin/formail -a "X-Date-Received: " $NOW

Obviously I miss something here?  There are already Received:-Headers in
emails which contain the date when the mail was received.  How do I
search on arbitrary headers?  This is especially difficult since date
specifications are so complex.

Ciao; gregor