It is worth listing the contents here to emphasise diversity of topics covered. These are several online books in HTML format, such as the System Administrators Guide, SAG , the Network Administrators Guide, NAG , the Linux Programmers Guide, LPG . RedHat seems to no longer ship this with their base set of packages. Some packages may install documentation here so that it goes online automatically if your web server is running. Apache is the most popular web server.
All packages installed on the system have their own individual documentation directory.
This most often contains documentation released with the sources of the package, such as release information, feature news, example code, FAQ's that are not part of the FAQ package, etc. In some cases, the package had complete references. Manual pages were discussed in Section 4.7 . Info pages were discussed in Section 4.8 .