Sorry, this isn't a bug. -k1,$n doesn't sort on the first $n fields but on the numeric prefix of the first $n fields, i.e. the `/' tab character separating fields 1 and 2 stops the comparison.
** Changed in: coreutils (Ubuntu) Status: Confirmed => Rejected -- sort's -u is Failing to Check all -k fields for Uniqueness. https://launchpad.net/bugs/56891 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs