note merlyn Yeah, it's not an obfuscation by any means. Just a nice way to put together a lot of common features. In fact, I'd take it one step further to fulfill one additional monkey wrench thrown in after that posting was made: what if the line appears more than once in either fileA or fileB or both, but you still want only one copy of the line? <p> Well, the answer is just as straightforward. Remove the dollar from the regex! I'll leave <i>that</i> explanation as an exercise to the clever reader. {grin} <p>-- <a href="http://www.stonehenge.com/merlyn/">Randal L. Schwartz, Perl hacker</a></p> <hr> <b>update:</b> Bleh! My mistake, the dollar was <b>added</b> to handle this case! I knew I had needed to deal with multiple hits somehow. <p> Remind me never to post again. {grin} 36725 46492