will search in all the database files *.db located (recursively) in
/tmp/mymail, for all the mails having "bob.something" as sender or
recipient, without "spam" in the subject, received over the last 31
will search in all the database files *.db located (recursively) in
/tmp/mymail, for all the mails having "bob.something" as sender or
recipient, without "spam" in the subject, received over the last 31