For macOS 10.10 and later only. This script will allow you to merge the track contents of two or more playlists to a new or existing playlist or delete any number of playlists at once, including Smart, Genius, and Playlist Folder playlists. The merge feature will prevent the same tracks that may appear in different source playlists from being duplicated and has an option to delete original playlists. The delete feature only deletes playlists; tracks, of course, remain in the library.
Also see Delete Empty Playlists.
About to merge the selected playlists to a single new playlist. The tracks in the selected playlists will be copied to the target playlist.
(via in-app purchase)
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