One of Linux's most underused capabilities by Windows administrators is the online help system. Like Windows, Linux offers an in-depth set of technical manuals that are always available to you. You access Linux Help by using the man command, which is short for manual. To display information (e.g., uses, options) about a command, program, or file, you type man followed by the name of the command you want to learn about. For example, to display information about the ls command, which works like the DOS Dir command, enter

# man ls

The information that's displayed on screen is called a man page. In a man page, you use the Up Arrow and Down Arrow keys to scroll through the text. You also can press the spacebar to page down one screen (80 lines) at a time.