Earlier quoted context omitted.
Seconded. However, I would add that most books which have Brian Kernighan as an author are of comparable quality. I'm yet to find a book that hasn't taught me something useful written by the man. I can quite confidently say that if he wrote a cook book, I'd go and buy it. Other books by him. 1. The UNIX programming environment 2. The Practice of Programming 3. The Go Programming Language
The AWK book is also pretty good; I read through it a few months ago, and pretty much all of it still works with a modern AWK (such as GNU AWK). The Go book was mostly written by Alan Donavan, according to Kernighan anyway (as stated in some interviews), but he's not the bragging sort so he might be underselling his contribution.
https://en.m.wikipedia.org/wiki/AWK
And Brian Kernighan has done a lot more than what I've read in this thread so far (though I've not read the full thing yet, and of course, it changes over time).
His overall influence on the field of software also extends far beyond his own direct work.
https://en.m.wikipedia.org/wiki/Brian_Kernighan
He is one of my top software gurus, since early in my career, since I worked a lot with Unix, from early on, but not only due to his Unix work and writing. I've used the knowledge and wisdom in some of his books to great advantage, throughout my career, and will be forever thankful to him and the rest of the early as well as later Unix "gang" for that.