How about supporting negative POS values for -k to count from the last field? Useful when there are a varying number of fields. Crazy?
E.g., two-line file x/y/z a/b desired to sort on last field via: sort -t/ -k -1,-1 Clearly there are ways to achieve the goal, e.g., extract and duplicate the last field to the beginning, or use Perl/awk/whatever to do the sorting, but ... just thought I'd throw it out there ... -k
