I am using the “Remove Duplicate Cards” addon available at https://ankiweb.net/shared/info/95590040 .
To install it
start anki on the command line -> Tools -> Add-ons -> Get Add-ons -> enter the code displayed on the addon page (ex:- 95590040)
Ref:-
Notes:
I have not found a way to do this directly on ankiweb.net.
today | 2021-11-09
% anki --version anki 2.1.8 % dpkg -l anki | grep ^ii ii anki 2.1.8+dfsg-1 all extensible flashcard learning program
today | 2020-11-09
tags | plugins
Settings → Security & privacy → Privacy → Permission manager → Files → “See more apps that can access all files” → AnkiDroid.A → Allow access to manage all files → drag to the right.