Mutt

mutt is an alternative MUA (Mail user agent) also known as mail client, for UBOs. It also as a windows version apparently which "may require cygwin. Mutt is not for the faint of heart, it has one of the steepest learning curves for an MUA, but as a result it's one of the most powerful and configurable.

.muttrc
set move="no" my_hdr From: me@example.com set from="\"John Doe\" " set use_from set edit_headers="yes" mailboxes /var/mail/dog ~/Mail/OpenBSD-bugs ~/Mail/OpenBSD-cvs
 * 1) This will prevent your read email from being moved to another folder.
 * 1) Change my From: header
 * 1) To be able to edit headers inline:
 * 1) browse through multiple mailboxes with "tab"
 * 2) and 'c' keys, that way you can have procmail sort your mail
 * 3) and you just let mutt select through them...

External reading
Mutt manual