note space_monk Yes instead of using grep, why aren't you using hashes to determine whether there is anything new in the file? You can build up a hash of all the terms (machines) in file1 and then check the hash to see whether an entry exists for each line of file2. <p>This would be much quicker than using grep for what you seem to be doing. <!-- Node text goes above. Div tags should contain sig only --> <div class="pmsig"><div class="pmsig-880879"> A Monk aims to give answers to those who have none, and to learn from those who know more. </div></div> 1003945 1003945