I did read it straight through up to chapter 7 (which was ostensibly Perl-centric). I felt like much of the material here was for the benefit of people like Larry Wall and John Ousterhout. I'm no dummy (I once wrote a crude "search & replace" facility for an HP48 calculator of all things), but a lot of material was a bit beyond what I would need. I just wanted something to help me do what I needed to do in vi without reading the help docs which don't help at all.

Fortunately everything a mere mortal would ever have to worry about regular expressions is explained quite explicitly in the first 50 pages. Buy the book, read the first 50 pages, learn a lot, and impress your colleagues who browse through the rest of the book...unless you actually are a programming language programmer.