| The following typographical conventions are used in this book: -
- Italic
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Indicates new terms, example URLs, email addresses, filenames, file extensions, pathnames, directories, and Unix utilities. -
- Constant width
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Indicates commands, options, switches, variables , attributes, keys, functions, types, classes, namespaces, methods , modules, properties, parameters, values, objects, events, event handlers, XML tags, HTML tags, macros, the contents of files, or the output from commands. -
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Constant width bold -
Shows commands or other text that should be typed literally by the user , and is used to emphasize code in examples. -
- Constant width italic
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Shows text that should be replaced with user-supplied values. In some cases where text is already italicized, user-supplied values are shown in angled brackets (< >)  | This icon signifies a tip, suggestion, or general note. | |
 | This icon indicates a warning or caution. | |
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