This was the first book related to UNIX I ever read cover to cover and a frequent reread/reference. While bash emerged as the shell standard via Linux, I’ll always have an affinity for csh due to cutting my teeth on it for shell scripting.
I used this book to learn more than just the fundamentals of C shell programming. Sometimes it is more efficient to switch to or supplement with the C shell and save many borne shell steps to accomplish the same process. The C shell environment is robust. What the C shell is not is intuitive. Therefore, you need this book for any serious scripting. One example of the usefulness of the book is the use of the “here” document. Here documents can be found in other shells also but if you want to know how to use this function and take in literal information without substitution then you will need to read this book.