| This book uses the following typographical conventions: -
- Italic
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Indicates the names of files, databases, directories, hostnames, domain names, usernames, sendmail feature names , Unix utilities, programs, and it is used to emphasize new terms when they are first introduced. -
- Constant width
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Indicates sendmail.cf literals, commands and variables , m4 macros and built-in commands, and Unix command-line options. It is used to show the contents of files and the output from commands. Keywords are also in constant width . -
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Constant width bold -
Used in examples to show commands or text that you would type. -
- Constant width italic
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Used in examples and text to show variables for which a context-specific substitution should be made. (The variable filename , for example, would be replaced by some actual filename.) -
- $ , #
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When we demonstrate commands that you would give interactively, we normally use the default Bourne shell prompt ( $ ). If the command must be executed as root , then we use the default superuser prompt ( # ). -
- [ option ]
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When showing command syntax, we place optional parts of the command within brackets. For example, ls [ -l ] means that the -l option is not required. | | This icon signifies a tip, suggestion, or general note. | | | | This icon indicates a warning or caution. | | |