This script scans the installed packages in macports and
uninstalls them if they do not have any dependents and
is not in the "world" file provided.

syntax:
    $ port_purge [WORLD_FILE]

TODO: [OPTIONS] is used when executing port uninstall 
[WORLD_FILE] is list of packages that should be excluded

This code is in public domain.

Author: Timothy Kim (timothykim@timothylive.net)


Example Usage:

$ port_purge
Searching for installed packages with no dependents...
- autoconf
- git-core
- lame
- wget
Found 12 packages.
> Would you like to uninstall found packages? (y/[n]) : n

$ cat world
git-core
lame
wget

$ port_purge world
- autoconf
Found 3 packages.
> Would you like to uninstall found packages? (y/[n]) : y
--->  Deactivating autoconf @2.63_0
--->  Uninstalling autoconf @2.63_0
> Would you like to scan again? ([y]/n) : y
Searching for installed packages with no dependents...
No packages found.

$