The Little Brother's Database (lbdb) consists of a set of small tools
that collect mail addresses from several sources and offer these
addresses to the external query feature of the Mutt mail reader.

To use the fetch address feature, put the following lines in your
.procmailrc:

:0hc | lbdb-fetchaddr

To use the database in mutt, put the following line into your .muttrc:

set query_command="lbdbq %s"