Concatenate is a plugin filter for Adobe Illustrator that connects two or more paths into one continuous path. You tell it how close the endpoints should be to combine the paths, how close to tangent the endpoints must be, and whether to average the endpoints and control handles together. It's especially useful for cleaning up CAD drawings and EPS files that have been converted to Adobe Illustrator or, for example, connecting and filling state/country borders in vector map files.
   The plugin also includes Assimilate, which will search out unselected paths that are within the distance and angle you specify, and concatenate them.
   Also included is Connect, which adds line segments connecting selected open paths.