| The following typographical conventions are used in this book: - Italic
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Used for filenames, directory names , and URLs. It is also used for emphasis and for the first use of a technical term . - Constant width
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Used for examples and to show the contents of files and the output of commands. -
Constant width bold -
Indicates user input in examples showing an interaction (e.g., a Listener session). - UPPERCASE
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In syntax descriptions, usually indicates keywords. - lowercase
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In syntax descriptions, usually indicates user-defined items such as variables . - [ ]
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In syntax descriptions, square brackets enclose optional items. - { }
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In syntax descriptions, curly brackets enclose a set of items from which you must choose only one. -
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In syntax descriptions, a vertical bar separates the items enclosed in curly brackets, as in {ON OFF YES NO TRUE FALSE}. - ...
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In syntax descriptions, ellipses indicate repeating elements. In addition, since repetition is rarely mandatory, the second occurrence of a syntax element is enclosed within square brackets. The following syntax, for example, indicates that you can have a comma-delimited list of naming methods : naming_method [ ,naming_method... ] Given this syntax, any of the following would be acceptable: TNSNAMES TNSNAMES, ONAMES TNSNAMES, ONAMES, HOSTNAME  | Indicates a tip, suggestion, or general note. For example, we'll tell you if a certain setting is version-specific. | |  | Indicates a warning or caution. For example, we'll tell you if a certain setting has some kind of negative impact on the system. | | |
