* usage examples

% ./src/bgpdump2 --help

% ./src/bgpdump2 ../ribs/rib.20140817.1500.bz2

% ./src/bgpdump2 ../ribs/rib.2014081{7,8}.1500.bz2

% ./src/bgpdump2 ../ribs/rib.2014081{7,8}.1500.bz2 --count

% ./src/bgpdump2 ../ribs/rib.20140817.1500.bz2 -k

% ./src/bgpdump2 ../ribs/rib.20140817.1500.bz2 --peer 1

% ./src/bgpdump2 ../ribs/rib.20140817.1500.bz2 -p 1 -l 8.8.8.8

% ./src/bgpdump2 ../ribs/rib.20140817.1500.bz2 -p 1 -L <addr-file>

% ./src/bgpdump2 ../ribs/rib.20140817.1500.bz2 -u -p 1 -p 2

% ./src/bgpdump2 ../ribs/rib.20140817.1500.bz2 -u -r -p 1 -p 2

udiff:
<: the prefix is in left and unreachable in right (maybe partially).
+: the prefix is only in right (but it is reachable in left).
): the prefix is in right, and is covered by a shorter prefix in left
   that is unreachable in right. (i.e., the shorter is '<')
>: the prefix is in right and unreachable in left (maybe partially).
-: the prefix is only in left (but it is reachable in right).
(: the prefix is in left, and is covered by a shorter prefix in right
   that is unreachable in left. (i.e., the shorter is '>')

% ./src/bgpdump2 ../ribs/rib.20140817.1500.bz2 -U -r -p 1 -p 2

verbose udiff:
{: the prefix to compare is in the left peer.
}: the prefix to compare is in the right peer.