These are two more of O'Reilly's pocket size references, low page count and small page size. The format isn't quite suitable for your breast pocket but pretty close. The books in this format best suit those who are reasonably familiar with the relevant topic but need a quick memory jogger that they can carry around with them. I find them somewhat expensive for what they are but if they meet a need that you have you probably are not going to worry about the price.
If you are on the move and need a quick memory jogger for sed and awk or for Java server pages then the relevant choice of these books will do the job. If you always have your reference bookshelf to hand then stick with the more comprehensive books.