UltraEdit, UltraCompare, UEStudio forums

How to find non consecutive duplicate lines in a large file? My file(s) could be rather large, about 60k to 100k lines. I tried it with this regular expression: (?-s)^(.+)\R(?s)(?=.*\R\1\R?) This works fine in Notepad++, but only for a small file. That is the reason why I' looking for something simi...