Cautionary 

For finding information quickly, searching with Google is often the best method. You can look up commands, symbols or messages that you don’t recognize, and generic (that is, not specific to your program) compiler errors/warnings with Google. Wikipedia can also be a valuable resource, as can be seen by the numerous links to Wikipedia articles throughout this appendix and the guide as a whole. In addition, consider making the man and info pages (which are discussed in Chapter 2, Built-in help system) the first place you look for information about commands, given that they often have the information you need and are immediately available.

If you would prefer to read books, those published by O’Reilly are often useful sources of information about Linux and other open source software products. Many of those books would be available through a public or university library, either on the shelf or electronically through Safari Books Online if your library is a subscriber. Selected relevant titles from O'Reilly and other publishers are listed in the sections that follow.