Getting Help
The vast majority of Linux systems are reasonably well documented with respect to the system programming interfaces and standard utilities. This is true because, since the earliest UNIX systems, programmers have been encouraged to supply a manual page with their applications. These manual pages, which are sometimes provided in a printed form, are invariably available electronically.
The man command provides access to the online manual pages. The pages vary considerably in quality and detail. Some may simply refer the reader to other, more thorough documentation, while others give a complete list of all options and commands that a utility supports. In either case, the manual page is a good place to start.
The GNU software suite and some other free software use an online documentation system called info. You can browse full documentation online using a special program, info, or via the info command of the emacs editor. The benefit of the info system is that you can navigate the documentation using links and cross-references to jump directly to relevant sections. For the documentation author, the info system has the benefit that its files can be automatically generated from the same source as the printed, typeset documentation.