@guy038 said in Delete line with duplicate Number: Hi, @jim-erlich and All, Many thanks for all your information ! It should be very easy to get the right solution ! The most important points are : Your file is already sorted by ascending #number And, in case of 1 duplicate line, it is located right after the original line ! Now, I don’t know how your preliminary sort behaved with numbers, separated with a space char from the # symbol ? For instance : Are lines sorted, as below ( case A ) : The dog went to the park - #4599 The cat went to the park - # 4657 The kid went to the park - #4797 The lizard went to the zoo - # 5100 The cat went to the zoo - #5120 OR Are lines sorted, like ( case B ) : The cat went to the park - # 4657 The lizard went to the zoo - # 5100 The dog went to the park - #4599 The kid went to the park - #4797 The cat went to the zoo - #5120 Indeed, the N++ sort would place the line # 10000 before the line #5000, as space code-point is smaller than code-point of a digit ! Anyway, assuming a sort, like in case A and the initial text : The dog went to the park - #4599 You went to the zoo - # 4640 He went to the park - # 4640 The cat went to the park - #4657 The kid went to the park - # 4657 The girl went to the park - #4900 The lizard went to the zoo - # 5100 The cat went to the zoo - #5100 I went to the park - #7500 We went to the zoo - #7500 They went to the park - #14000 Here is the road map : Open your file in N++ Open the Replace dialog ( Ctrl + H ) SEARCH (?-s)^.+#\x20?(\d+)\R(?=.+#\x20?\1) REPLACE Leave EMPTY Tick the Wrap around option Select the Regular expression search mode Click once on the Replace All button or several times on the Replace button Voila ! You should get your expected list : The dog went to the park - #4599 He went to the park - # 4640 The kid went to the park - # 4657 The girl went to the park - #4900 The cat went to the zoo - #5100 We went to the zoo - #7500 They went to the park - #14000 Note that if your sort is rather like in case B, it shouldn’t be be difficult to get, again, the case A order and run the regex S/R, afterwards ;-)) Next time, if everything was OK, I’ll explain how this regex S/R works ! Best Regards, guy038 Flawless… absolutely amazing. You don’t understand how thankful I am for your detailed and correct response. This is a whole new language for me and I am amazed. thank you again.

Thank you, it works :)

@jiskapav Does Notepad++ support “OVERWRITE” in column mode? Based on the information provided, and some experimentation on my part, I’d say the answer is Yes. But see HERE.

@Stefan-Pecen Replace In Files has always (or for a really long time) had a confirmation popup, when used interactively or via macros. Replace All in All Opened Documents has recently (7.8.8) been given a confirmation popup, probably due to users complaining that it is an operation that is easily invoked by mistake. Perhaps for both of these commands, if running via macro, there should be no confirmation? You’d have to confirm while recording the macro, that should be enough to give you the hint that the operation should be used with care. There is no “setting” governing this behavior. If you’d like to make a feature request, you need to do that by following instructions HERE.