"There are some tools that look like you will never replace them. One of those (for me) is grep. It does what it does very well (remarks about the shortcomings of regexen in general aside). It works reasonably well with Unicode/UTF-8 (a great opportunity to Fail Miserably for any tool, viz. a2ps).
"Yet, the other day I read about ack, which claims to be 'better than grep, a search tool for programmers.' Woo. Better than grep? In what way...?"