Specifically, the command:
sudo port list installed
Shows doubles of packages, like this:
apache2 @2.2.21 www/apache2
apache2 @2.2.21 www/apache2
...
ncurses @5.9 devel/ncurses
ncurses @5.9 devel/ncurses
php5-iconv @5.3.8 php/php5-iconv
php5-iconv @5.3.8 php/php5-iconv
php5-intl @5.3.8 php/php5-intl
php5-intl @5.3.8 php/php5-intl
...
Why is this?
How did it happen and how do I fix it?
From macports bug list
The inactive versions are older ports that have been replaced by newer ones that are active.
port list inactiveshows the ports that are not used any more and in your case should show one of each duplicate (or 2 or triplets etc)port uninstall inactivewill remove the inactive ports and leave you with just one.