In the mail examples in Section 4.3.3.2 when we looked at a pattern such as /From:/, /Date:/ or
/Subject:/, we essentially said that the pattern can occur anywhere in the target string, not at a specific location. For example, if we search for the pattern /From:/ in the /usr/spool/mail/kalita file we talked about earlier, it matches each one of the following four lines because each one contains the substring From:.
From: "Brahma, Malavika (Exchange)" <MBrahma@Bear.COM>
> From: J. Kalita [SMTP:kalita@pikespeak.uccs.edu]
> > > From: Chatterjee, Rajeeb [SMTP:rajeeb.chatterjee@intel.com]
> > > > From: KBhuyan@aol.com [SMTP:KBhuyan@aol.com]
Now, if we are dealing with a mail file in Unix, the first corresponds to a complete message from
MBrahma@Bear.COM in the mailbox file whereas the second corresponds to a message included or forwarded from kalita@pikespeak.uccs.edu. This forwarded message in turn contains two recursively forwarded or included messages. Most mailer programs indent included or forwarded messages and precede each line or an included message with a certain character such as > for each level of inclusion or forwarding.