How to list which revisions are available for activation?

[Jim DeLaHunt]

This may be a stupid question, but I can't find the answer in the help file.

How can I find out which revisions of a particular port are present 
on my system?

Consider the following.  "port info" tells me which is the highest 
revision loaded on my system.  However, "port outdated" tells me that 
what is active is a slightly older revision.  What I want is a 
command which will tell me, "you have version a.b.c_d and version 
m.n.o_p, and it's version a.b.c_d which is activated".

% port outdated dbus
The following installed ports are outdated:
dbus                           1.2.12_4 < 1.2.12_5
% port info dbus
dbus @1.2.12, Revision 5 (devel)
Variants:    darwin_7, no_root, no_startupitem, test, universal

A message bus system, a simple way for applications to talk to one another.
Homepage:    http://www.freedesktop.org/Software/dbus

Build Dependencies:   pkgconfig, autoconf, automake, libtool
Library Dependencies: expat
Platforms:            darwin
Maintainers:          mcalhoun at macports.org openmaintainer at macports.org

Thanks in advance,
-- 
     --Jim DeLaHunt, jdlh at jdlh.com     http://blog.jdlh.com/ (http://jdlh.com/)
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