Hi, There seems to be a bug in uniq. To duplicate: Use attached file and run it through uniq with -d. It then gives no output. If uniq is run without a flag then the original file is output from uniq. Gerrie@GerrieM /cygdrive/c/adhoc/vodacom $ uniq -d a.txt Gerrie@GerrieM /cygdrive/c/adhoc/vodacom Gerrie@GerrieM /cygdrive/c/adhoc/vodacom $ uniq a.txt 084699880820120120100749 084800053520120120100741 084800053520120120100741 Gerrie@GerrieM /cygdrive/c/adhoc/vodacom $ uniq --version uniq (GNU coreutils) 8.10 Packaged by Cygwin (8.10-1) Copyright (C) 2011 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later . This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by Richard M. Stallman and David MacKenzie. This happens in the current version as well as 8-15-1. Gerrie Myburgh, Software Developer www.bbd.co.za Nashua Mobile (Pty) Ltd 42 James Crescent, Halfway House, Midrand, Gauteng, South Africa. This e-mail is confidential and subject to the disclaimer published on the BBD website .