#!/bin/bash
## form the set-difference of 2 files;  Eugene Reimer  2010-04;
## for files that are set-like / uniquified, but need not be sorted  (for sorted files using join or comm may be slightly faster):
## see also:  SetUnion  SetIntersection;
##
## This and other useful one-liners are found in:  http://www.pixelbeat.org/cmdline.html
##	he calls it SetDifference, and has $1, $2 reversed to my way of thinking;
##	==my ListSubtract* scripts could be adapted to this method==??==

sort "$1" "$2" "$2" |uniq -u