Originally posted by orgazmo Someone else told me to use sed...
Not here, though. That's the main reason why double- (or more) posting is forbiden by the forum rules.
Glad for you that it works, though. As for the grep part, that's for checking for the presence of the selected line(s) (you may select lines differently if you wish) in the second file, but only if the full (-x) line matches, and in "plain text" (-F), not as a regular expression.