Why is "less" much slower than "grep"?

I sometimes have to look through files that are several gigs and have noticed that finding what I am looking for with grep is much faster than with less. Why could that be? I am talking about looking for a certain tag/word, not even any complicated regex.


By default, 'less' calculates line numbers, which can slow it down. Try using the '-n' option to suppress line number calculations and see if that speeds things up.