For an experienced shell programmer, this is actually a good read. Seebach touches on a lot of new and improved thinking in UNIX shells, with a good focus on what is POSIX. This is a twenty first century book, unlike most shell programming books that I have read. He focuses on bash, but why not. Bash is the default shell on just about every system that I have logged into for the past decade. Solaris and the Korn shell are dying.