On Tue, Apr 03, 2007 at 08:19:10PM +0800, Jeff Zhang wrote: > I have a simple txt file, like: > ... > a a > aa a > b b > ba b > ... > > I want to just keep the lines that first appeared in column 2 and delete the > follow lines that contain duplicated ones in column 2. > then it will like: > ... > a a > b b > ... > > I've tried `uniq -f1` but it didn't work. So write a python script. Doug.