One of the nice things about eBooks is the saving that you can make on buying one instead of the dead tree edition. And if you get one from Apress, it is the full article that you get and they keep it available so that you can download another version if you need it. You can also print the thing off if you want too but a laser printer producing double-sided prints is an asset if you don’t want your space invaded by a hoard of lever arch binders. Having a copious supply of inexpensive toner helps too as does cheap paper. Otherwise, you could spend your savings on printing the thing yourself.
The ever pervasive Safari does things a little differently from the likes of Apress. Mind you, the emphasis there is on the library aspect of the operation and not eBook selling. The result is that you can only ever download chapters, so no index or overall table of contents. You still can buy all of the chapters for a particular book, though some publishers don’t seem to allow this for some reason, but finding anything in there after you have had a read becomes an issue, especially when it’s the hard copy that you are using. Take yesterday, for instance, when trying to relocate the formatting parameters for the UNIX date function. I eventually found them in the chapters of UNIX in a Nutshell that I have downloaded and printed off but I spent rather longer looking in Learning the Korn Shell than I should have done. I know that you can search in the PDF’s themselves but that is more laborious when there is a number of files to search rather than just the one. I suppose that the likes of O’Reilly prefers you to buy paper copies of its books for more extensive use, and they have a point, but having the electronic version all in one file does make life so much easier.