Merging files without duplicates

[mweaver]

Hi All,

How can I merge a set of shape files and remove duplicates?

when I use:

ogr2ogr -f "esri shapefile" -update -append

The shape files are appended together but it duplicated the shapes in the file.  

Is there a way to remove the duplicates or merge them while (removing/ignoring) the duplicates?

Thanks,
Mike