The man pages are UNIX on-line help. They contain almost everything to define how UNIX works, but are often obscure. Examples are rare. Some topics are difficult to find because they are features of a shell program, such as the else command of the ksh shell, rather than functions of basic UNIX itself. All Unix-like systems are provided with extensive manuals. Even if you don’t have the material printed on paper, you still have plenty of information installed with your OS. Most usually, manual pages are found under /usr/share/mandirectory. Manuals are not presented in clear text there’s a markup language commands which should be interpreted by the man command. The man pages are divided into sections and the same topic can occur in several sections of the man pages.