note naturalsciences <p>Yes it would break down but right now I'm specifically looking for neighbouring dupes :) (There is an actual reason to suspect they are positioned so in those files) It wouldn't be hard for me to write a push/shift code that would kind of like slide a 4-line long reading frame over the whole text file.</p><p> But I ran totally in a ditch trying to do the same so that the frame wouldn't "slide" but would be "lifted" four lines at a time. </p> <p>Then I could just </p> <p> <code> if ($frame&#91;1&#93;!=m/$frame&#91;3&#93;/){print @frame} <\code> </p> <p> But for some reason I mess the populating/emptying/and moving the frame up so readily. </p> edit: disregard all that - a sliding frame is exactly what I need. So I guess were done here :D. Thank you all! Learned a lot of other stuff on the side also :) 1007560 1007813