This was my first real "programming" book, and my first O'Reilly animal book and it changed the course of my life in a real and tangible sense. I read it cover to cover and did all off the exercises, and then moved right on to Learning Perl. To this day, I watch people struggle with regexes or dismiss them, but I'm done finding what they were looking for before they can finish complaining.
The appeal of Perl when I chose my first "real" programming language, after using Javascript for browser compatibility hacks, was that it was designed by a linguist with regular expressions built into the language as first class citizens. My flatmate at the time, who worked for a bank, was trying to persuade me that Java was the future but I took one look at Java's regex implementation, where you have to escape regex metacharacters, and nearly threw up. Java 17 still hasn't fixed this even after adding raw string literals.
